diff --git a/README.md b/README.md
index 253813b..c056f1b 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# UKT - Neurofeedback
+# NINFA
 
 Small Matlab Framework for running Custom Neurofeedback Protocols on LSL Streams
 
@@ -14,12 +14,20 @@ Small Matlab Framework for running Custom Neurofeedback Protocols on LSL Streams
 
 ## Configuration
 
-1. [Optional] Adjust `TYPE` of LSL input stream (default is for NIRS device) 
-2. Click `OPEN` to connect with LSL input stream
-3. Configure `SETTINGS`, `ID` and `EPOCHS`
-4. Click `START` to run a session
+1. Select your device
+2. [Optional] Adjust `TYPE` of LSL input stream
+3. Click `OPEN` to connect with LSL input stream
+4. Configure `SETTINGS`, `ID` and `EPOCHS`
+5. Click `START` to run a session
 
-![ukt-nf-settings](https://github.com/cyberjunk/ukt-nf/assets/780159/0690b24e-7a20-4357-bd0d-9171c880115d)
+![ninfa](https://github.com/user-attachments/assets/7f8ba7ad-ea09-4d08-8384-57f182961430)
+
+### DEVICE
+
+* Select your device type and model from the available options.
+* Add a device by creating a `.json` file for it in subfolder `devices`
+  * Take a look at the existing `nirs_nirx_nirsport2.json`
+  * The most important part is defining the LSL channels sent by the device
 
 ### LSL STREAM
 
@@ -38,10 +46,10 @@ Small Matlab Framework for running Custom Neurofeedback Protocols on LSL Streams
 
 | Setting              | Description                                                                                    |
 |----------------------|------------------------------------------------------------------------------------------------|
-| `SELECTED CHANNELS`  | Comma separated list of LSL input channel numbers to use (others are ignored).                 |
+| `PROTOCOL`           | The Matlab file from folder `protocols` with algorithm executed on each window.                |
+| `CHANNELS`           | Select LSL channels to use in the selected protocol                                            |
 | `WINDOW SIZE (S)`    | Size of the sliding window in seconds. The window always contains last n seconds of samples.   |
 | `SESSION LENGTH (S)` | The session will automatically stop after this time.                                           |
-| `PROTOCOL`           | The Matlab file from folder `protocols` with algorithm executed on each window.                |
 
 ### ID
 
@@ -88,8 +96,9 @@ An epoch is a configurable timespan within a session.
 
 * A protocol calculates a feedback value from an input window
 * To add a protocol put the Matlab file in subfolder `protocols`
-* See `example1.m` (returns a random feedback value)
-
+* The `Gauss.m` example requires a NIRS device that sends at least one `HbO` channel with `μmol/L` unit
+* The `RecordOnly.m` works with any device type and model and just records data
+ 
 ## Drift and Execution Times
 
 * `DRIFT` shows current offset in playback schedule (`where we are` vs. `where we should be`)
diff --git a/components/devices.m b/components/devices.m
new file mode 100644
index 0000000..9aa267b
--- /dev/null
+++ b/components/devices.m
@@ -0,0 +1,66 @@
+classdef devices < handle
+    %Devices
+    %   Detailed explanation goes here
+
+    properties (Constant)
+        types = ["NIRS", "EEG"]
+    end
+    
+    properties
+        nirs     struct = [];
+        eeg      struct = [];
+        selected struct = struct([]);
+    end
+    
+    methods
+        function self = devices()
+            self.reload();
+        end
+        
+        function reload(self)
+            files = ls("devices/*.json");
+            for f = 1:size(files, 1)
+                file = files(f, 1:end);
+                json = jsondecode(fileread("./devices/" + file));
+                switch json.type
+                    case "NIRS"
+                        idx = length(self.nirs) + 1;
+                        self.nirs(idx).name = json.name;
+                        self.nirs(idx).type = json.type;
+                        self.nirs(idx).lsl = json.lsl;
+                    case "EEG"
+                        idx = length(self.eeg) + 1;
+                        self.eeg(idx).name = json.name;
+                        self.eeg(idx).type = json.type;
+                        self.eeg(idx).lsl = json.lsl;
+                    otherwise
+                        disp("Ignoring unknown device type");
+                end
+            end
+        end
+        
+        function r = select(self, type, name)
+            switch type
+                case "NIRS"
+                    for d = 1:length(self.nirs)
+                        if self.nirs(d).name == name
+                            self.selected = self.nirs(d);
+                            r = true;
+                            return
+                        end
+                    end
+                case "EEG"
+                    for d = 1:length(self.eeg)
+                        if self.eeg(d).name == name
+                            self.selected = self.eeg(d);
+                            r = true;
+                            return
+                        end
+                    end
+                otherwise
+                    warning("Ignoring unknown device type: " + type);
+            end
+            r = false;
+        end
+    end
+end
diff --git a/components/protocols.m b/components/protocols.m
new file mode 100644
index 0000000..b77c174
--- /dev/null
+++ b/components/protocols.m
@@ -0,0 +1,67 @@
+classdef protocols < handle
+    %Protocols
+    %   Detailed explanation goes here
+
+    properties (Constant)
+    end
+    
+    properties
+        list     struct = []
+        selected struct = struct([]);
+    end
+    
+    methods
+        function reload(self, device)
+            self.list = [];
+            self.selected = struct();
+            files = ls("protocols/*.m");
+            for f = 1:size(files, 1)
+                file = files(f, 1:end);
+                name = strtrim(erase(file, ".m"));
+                fh = feval(name);
+                req = fh.requires();
+                if ~self.iscompatible(req, device)
+                    continue
+                end
+                idx = length(self.list) + 1;
+                self.list(idx).name = name;
+                self.list(idx).fh = fh;
+                self.list(idx).req = req;
+            end
+        end
+        
+        function r = iscompatible(~, req, dev)
+            % check device type
+            if req.devicetype ~= "ANY" && req.devicetype ~= dev.type
+                r = false;
+                return
+            end
+            % check channel requirements
+            for idx = 1:length(req.channels)
+                found = 0;
+                for lslch = 1:length(dev.lsl.channels)
+                    if req.channels(idx).type == dev.lsl.channels(lslch).type && ...
+                       req.channels(idx).unit == dev.lsl.channels(lslch).unit
+                       found = found + 1;
+                    end
+                end
+                if found < req.channels(idx).min
+                    r = false;
+                    return
+                end
+            end
+            r = true;
+        end
+        
+        function r = select(self, name)
+            for p = 1:length(self.list)
+                if self.list(p).name == name
+                    self.selected = self.list(p);
+                    r = true;
+                    return
+                end
+            end
+            r = false;
+        end
+    end
+end
diff --git a/components/session.m b/components/session.m
index ca38d0b..16af9ca 100644
--- a/components/session.m
+++ b/components/session.m
@@ -14,12 +14,16 @@
         protocolavg double  = 0.0;        % avg tracked protocol exec time
         protocolsum double  = 0.0;        % sum tracked protocol exec time
         srate       double  = 0.0;        % sample rate
+        device      struct  = struct();   % device used in session
         channels    uint32  = [];         % channel numbers
-        data        double  = zeros(0,0); % session data
+        fn          cell    = [];         % field names in data and window
+        data        struct  = struct();   % session data
+        datasize    uint32  = 0;          % rows count in data
         times       double  = zeros(0);   % timestamps of sesssion data
         idx         uint32  = 0;          % current index in data and times
         firsttime   double  = 0.0;        % first time       
-        window      double  = zeros(0,0); % current window
+        window      struct  = struct();   % current window
+        windowsize  uint32  = 0;          % rows count in window
         windowtimes double  = zeros(0);   % current window times
         windowidx   uint32  = 0;          % current index in window
         windownum   uint32  = 1;          % current window num
@@ -32,7 +36,6 @@
         study       string  = "";         % name of study
         subject     uint32  = 1;          % subject numer
         run         uint32  = 1;          % run number
-        ploth       matlab.ui.Figure;
     end
     
     events
@@ -43,36 +46,56 @@
     end
     
     methods
+        %% Return Channel Counts for each Type
+        function r = countChannelTypes(self)
+            r = struct();
+            lslchannels = self.device.lsl.channels;
+            numlslchannels = length(lslchannels);
+            for ch = self.channels
+                type = "unknown";
+                if ch <= numlslchannels
+                    type = lslchannels(ch).type;
+                end
+                if ~isfield(r, type)
+                    r.(type) = 0;
+                end
+                r.(type) = r.(type) + 1;
+            end
+        end
+        
         %% Start a new session
         function r = start(self, protocol, lengthmax, window, srate, ...
-                           channels, markerinfo, study, subject, run)
+                           device, channels, markerinfo, study, subject, run)
             if self.running
                 r = false;
                 return;
             end
-            if isvalid(self.ploth)
-                close(self.ploth);
-            end
-            numrows = ceil(srate*lengthmax);
-            numcols = length(channels);
-            numrowswnd = ceil(srate*window);
+            self.datasize = ceil(srate*lengthmax);
+            self.windowsize = ceil(srate*window);
             self.running = true;
             self.protocol = protocol;
             self.protocolmax = 0.0;
             self.protocolavg = 0.0;
             self.protocolsum = 0.0;
-            self.lengthmax = lengthmax;          
+            self.lengthmax = lengthmax;
             self.srate = srate;
+            self.device = device;
             self.channels = channels;
-            self.data = zeros(numrows, numcols);
-            self.times = zeros(numrows, 1);
-            self.feedback = zeros(numrows, 1);
+            counts = self.countChannelTypes();
+            self.data = struct();
+            self.window = struct();
+            self.fn = fieldnames(counts);
+            for k = 1:numel(self.fn)
+                self.data.(self.fn{k}) = zeros(self.datasize, counts.(self.fn{k}));
+                self.window.(self.fn{k}) = zeros(self.windowsize, counts.(self.fn{k}));
+            end
+            self.times = zeros(self.datasize, 1);
+            self.feedback = zeros(self.datasize, 1);
             self.idx = 0;           
-            self.window = zeros(numrowswnd, numcols);
-            self.windowtimes = zeros(numrowswnd, 1);
+            self.windowtimes = zeros(self.windowsize, 1);
             self.windowidx = 0;
             self.windownum = 1;
-            self.markers = zeros(numrows, 1);
+            self.markers = zeros(self.datasize, 1);
             self.markerinfo = markerinfo;
             self.marker = 0;
             self.bgcolor = [0 0 0];
@@ -84,6 +107,7 @@
             self.starttime = now();
             r = true;
             notify(self, "Started");
+            self.update()
         end
         
         %% Stop a running session
@@ -100,7 +124,6 @@
             r = true;
             notify(self, "Stopped");
             self.save();
-            self.plot();
         end
         
         
@@ -134,7 +157,7 @@ function update(self)
             if ~epochfound; self.marker = 0.0; end
             if epochold ~= self.marker; notify(self, "Epoch"); end
             %% stop session if required samples are recorded
-            if self.idx >= length(self.data)
+            if self.idx >= self.datasize
                 self.stop();
             end
             %% stop session if time is up
@@ -150,28 +173,47 @@ function pushSample(self, sample, ts)
             if ~self.running
                 return;
             end
-            %% save timestamp of first sample
+            %% increment index for sample
+            self.idx = self.idx + 1;
+            %% save timestamp
             if self.firsttime == 0
                 self.firsttime = ts;
             end
-            relts = ts - self.firsttime;
-            %% add sample to data
-            self.idx = self.idx + 1;
-            self.data(self.idx,:) = sample;
-            self.times(self.idx,:) = relts;
-            self.markers(self.idx,:) = self.marker;
-            %% add sample to window
-            if self.windowidx < length(self.window)
+            relts = ts - self.firsttime;          
+            %% shift window
+            if self.windowidx < self.windowsize
                 self.windowidx = self.windowidx + 1;
             else
-                self.window = circshift(self.window, -1);
+                for k = 1:numel(self.fn)
+                    self.window.(self.fn{k}) = ...
+                        circshift(self.window.(self.fn{k}), -1);
+                end
                 self.windowtimes = circshift(self.windowtimes, -1);
             end
-            self.window(self.windowidx,:) = sample;
             self.windowtimes(self.windowidx,:) = relts;
+            self.times(self.idx,:) = relts;
+            self.markers(self.idx,:) = self.marker;
+            %% add new sample to data and window
+            colidx = struct();
+            lslchannels = self.device.lsl.channels;
+            numlslchannels = length(lslchannels);
+            for i = 1:length(self.channels)
+                type = "unknown";
+                val = sample(i);
+                ch = self.channels(i);
+                if ch <= numlslchannels
+                    type = lslchannels(ch).type;
+                end
+                if ~isfield(colidx, type)
+                    colidx.(type) = 1;
+                end
+                self.data.(type)(self.idx, colidx.(type)) = val;
+                self.window.(type)(self.windowidx, colidx.(type)) = val;
+                colidx.(type) = colidx.(type) + 1;
+            end
             %% raise window event
             notify(self, "Window");
-            if self.windowidx >= length(self.window)
+            if self.windowidx >= self.windowsize
                 self.windownum = self.windownum + 1;
             end
         end
@@ -198,44 +240,30 @@ function save(self)
             export.subject = self.subject;
             export.run = self.run;
             % meta info
+            export.device = self.device;
             export.protocol = self.protocol;
             export.samplerate = self.srate;
             export.channels = self.channels;
             export.starttime = datetime(self.starttime,'ConvertFrom','datenum');
             export.stoptime = datetime(self.stoptime,'ConvertFrom','datenum');
             export.duration = self.length;
-            export.windowsamples = length(self.window);
+            export.windowsamples = self.windowsize;
             % data
+            for k = 1:numel(self.fn)
+                export.data.(self.fn{k}) = self.data.(self.fn{k})(1:usedrows,:);
+            end
             export.times = self.times(1:usedrows,:);
-            export.data = self.data(1:usedrows,:);
             export.feedback = self.feedback(1:usedrows,:);
             export.marker = self.markers(1:usedrows,:);
             % export
             studyname = "unnamed";
-            if self.study ~= ""; studyname = self.study; end          
+            if self.study ~= ""; studyname = self.study; end
             filename = ...
                 studyname + "-" + ...
                 sprintf('%03d', self.subject) + "-" + ...
-                sprintf('%02d', self.run);           
+                sprintf('%02d', self.run);
             save("./sessions/" + filename + ".mat", '-struct','export');
         end
-        
-        function plot(self)
-            self.ploth = figure('Name', 'Session Plot');
-            self.ploth.NumberTitle = 'off';
-            nchannels = length(self.channels);
-            for i = (1:nchannels)
-                subplot(nchannels+2,1,i);
-                plot(self.data(:,i));
-                title('Channel ' + string(self.channels(i)));
-            end
-            subplot(nchannels+2,1,nchannels+1);
-            plot(self.feedback(:,1));
-            title('Feedback');
-            subplot(nchannels+2,1,nchannels+2);
-            plot(self.markers(:,1));
-            title('Marker');
-        end
     end
 end
 
diff --git a/devices/eeg_generic.json b/devices/eeg_generic.json
new file mode 100644
index 0000000..e30301c
--- /dev/null
+++ b/devices/eeg_generic.json
@@ -0,0 +1,8 @@
+{
+  "name": "Generic",
+  "type": "EEG",
+  "lsl": {
+    "type": "",
+	"channels": []
+  }
+}
diff --git a/devices/nirs_generic.json b/devices/nirs_generic.json
new file mode 100644
index 0000000..d27271d
--- /dev/null
+++ b/devices/nirs_generic.json
@@ -0,0 +1,8 @@
+{
+  "name": "Generic",
+  "type": "NIRS",
+  "lsl": {
+    "type": "",
+	"channels": []
+  }
+}
diff --git a/devices/nirs_nirx_nirsport2.json b/devices/nirs_nirx_nirsport2.json
new file mode 100644
index 0000000..1d69478
--- /dev/null
+++ b/devices/nirs_nirx_nirsport2.json
@@ -0,0 +1,90 @@
+{
+  "name": "nirX NIRSport2",
+  "type": "NIRS",
+  "lsl": {
+    "type": "NIRS",
+    "channels": [
+      { "devch":  0, "type": "COUNTER", "unit": "" },
+      { "devch":  1, "type": "WL760NM", "unit": "V" },
+      { "devch":  2, "type": "WL760NM", "unit": "V" },
+      { "devch":  3, "type": "WL760NM", "unit": "V" },
+      { "devch":  4, "type": "WL760NM", "unit": "V" },
+      { "devch":  5, "type": "WL760NM", "unit": "V" },
+      { "devch":  6, "type": "WL760NM", "unit": "V" },
+      { "devch":  7, "type": "WL760NM", "unit": "V" },
+      { "devch":  8, "type": "WL760NM", "unit": "V" },
+      { "devch":  9, "type": "WL760NM", "unit": "V" },
+      { "devch": 10, "type": "WL760NM", "unit": "V" },
+      { "devch": 11, "type": "WL760NM", "unit": "V" },
+      { "devch": 12, "type": "WL760NM", "unit": "V" },
+      { "devch": 13, "type": "WL760NM", "unit": "V" },
+      { "devch": 14, "type": "WL760NM", "unit": "V" },
+      { "devch": 15, "type": "WL760NM", "unit": "V" },
+      { "devch": 16, "type": "WL760NM", "unit": "V" },
+      { "devch": 17, "type": "WL760NM", "unit": "V" },
+      { "devch": 18, "type": "WL760NM", "unit": "V" },
+      { "devch": 19, "type": "WL760NM", "unit": "V" },
+      { "devch": 20, "type": "WL760NM", "unit": "V" },
+      { "devch":  1, "type": "WL850NM", "unit": "V" },
+      { "devch":  2, "type": "WL850NM", "unit": "V" },
+      { "devch":  3, "type": "WL850NM", "unit": "V" },
+      { "devch":  4, "type": "WL850NM", "unit": "V" },
+      { "devch":  5, "type": "WL850NM", "unit": "V" },
+      { "devch":  6, "type": "WL850NM", "unit": "V" },
+      { "devch":  7, "type": "WL850NM", "unit": "V" },
+      { "devch":  8, "type": "WL850NM", "unit": "V" },
+      { "devch":  9, "type": "WL850NM", "unit": "V" },
+      { "devch": 10, "type": "WL850NM", "unit": "V" },
+      { "devch": 11, "type": "WL850NM", "unit": "V" },
+      { "devch": 12, "type": "WL850NM", "unit": "V" },
+      { "devch": 13, "type": "WL850NM", "unit": "V" },
+      { "devch": 14, "type": "WL850NM", "unit": "V" },
+      { "devch": 15, "type": "WL850NM", "unit": "V" },
+      { "devch": 16, "type": "WL850NM", "unit": "V" },
+      { "devch": 17, "type": "WL850NM", "unit": "V" },
+      { "devch": 18, "type": "WL850NM", "unit": "V" },
+      { "devch": 19, "type": "WL850NM", "unit": "V" },
+      { "devch": 20, "type": "WL850NM", "unit": "V" },
+      { "devch":  1, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  2, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  3, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  4, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  5, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  6, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  7, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  8, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  9, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 10, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 11, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 12, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 13, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 14, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 15, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 16, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 17, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 18, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 19, "type": "HbO",     "unit": "μmol/L" },
+      { "devch": 20, "type": "HbO",     "unit": "μmol/L" },
+      { "devch":  1, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  2, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  3, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  4, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  5, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  6, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  7, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  8, "type": "HbR",     "unit": "μmol/L" },
+      { "devch":  9, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 10, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 11, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 12, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 13, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 14, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 15, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 16, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 17, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 18, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 19, "type": "HbR",     "unit": "μmol/L" },
+      { "devch": 20, "type": "HbR",     "unit": "μmol/L" }
+    ]
+  } 
+}
diff --git a/main.m b/main.m
index 4832b5d..ee296be 100644
--- a/main.m
+++ b/main.m
@@ -19,14 +19,20 @@
 % globals
 global mylsl;
 global mysession;
+global mydevices;
+global myprotocols;
+global myselectchannels;
 global mysettings;
 global myfeedback;
 
 % init globals
-mylsl      = lsl();
-mysession  = session();
-mysettings = app();
-myfeedback = feedback();
+mylsl            = lsl();
+mysession        = session();
+mydevices        = devices();
+myprotocols      = protocols();
+myselectchannels = selectchannels();
+mysettings       = app();
+myfeedback       = feedback();
 
 % add listeners to lsl
 lhsample = addlistener(mylsl, "NewSample", @onNewSample);
@@ -72,21 +78,25 @@ function onNewSample(src, ~)
     mysession.update();
 end
 
-function onSessionStarted(~, ~)
+function onSessionStarted(src, ~)
     global mylsl;
     global myfeedback;
+    global myprotocols;
     mylsl.marker = 0;
     mylsl.trigger(100);
     myfeedback.showBar();
+    myprotocols.selected.fh.init();
 end
 
 function onSessionStopped(src, ~)
     global mylsl;
     global myfeedback;
+    global myprotocols;
     mylsl.marker = 0;
     mylsl.trigger(101);
     myfeedback.setBackground(src.bgcolor);
     myfeedback.hideBar();
+    myprotocols.selected.fh.finish(src);
 end
 
 function onSessionEpoch(src, ~)
@@ -103,21 +113,29 @@ function onSessionEpoch(src, ~)
 
 function onSessionWindow(src, ~)
     global myfeedback;
+    global myprotocols;
 
     prevfeedback = 0.5;
     if src.idx > 1
         prevfeedback = src.feedback(src.idx-1);
     end
     
+    prevmarker = 0;
+    if src.idx > 1
+        prevmarker = src.markers(src.idx-1);
+    end
+
     tick = tic();
-    r = feval (src.protocol, ...
+    r = myprotocols.selected.fh.process (...
         src.marker,    src.srate, ...
-        src.idx,       src.data(src.idx,:), ...
+        src.idx,       src.data, ...
         src.windownum, src.window, ...
-        src.windowidx >= length(src.window), ...
-        prevfeedback);
+        src.windowidx >= src.windowsize, ...
+        prevfeedback,  prevmarker);
     span = toc(tick);
     
+    r = min(max(r,0.0),1.0);
+    
     myfeedback.setFeedback(r);
     src.pushFeedback(r, span);
 end
diff --git a/protocols/Gauss.m b/protocols/Gauss.m
new file mode 100644
index 0000000..62f1622
--- /dev/null
+++ b/protocols/Gauss.m
@@ -0,0 +1,189 @@
+function fh = Gauss
+  fh.requires = @requires;
+  fh.init     = @init;
+  fh.process  = @process;
+  fh.finish   = @finish;
+end
+
+% REQUIREMENTS FOR PROTOCOL
+function r = requires()
+    r.devicetype = "NIRS";
+    % required window min and max durations
+    r.window.mins = 1.0;
+    r.window.maxs = 10.0;
+    % requires at least one HbO channel
+    r.channels(1).type = "HbO";
+    r.channels(1).unit = "μmol/L";
+    r.channels(1).min = 1;
+    r.channels(1).max = 64;
+    % HbR is optional
+    r.channels(2).type = "HbR";
+    r.channels(2).unit = "μmol/L";
+    r.channels(2).min = 0;
+    r.channels(2).max = 64;
+end
+
+% EXECUTED ONCE ON START
+function init()
+    global Filter
+    ordine = 15;
+    cutoff = 0.022;
+    Filter = gaussfir(cutoff, ordine);
+end
+
+% EXECUTED FOR EACH SLIDING WINDOW
+function r = process(...
+    marker, samplerate, samplenum, data, ...
+    windownum, window, isfullwindow, ...
+    prevfeedback, prevmarker)
+
+    % IMPORTANT: 
+    %   Your algorithm must take less than (1/samplerate) seconds 
+    %   in average or else you fall behind schedule and get a drift.
+    %   If you're algorithm requires more time than that then
+    %   run your calculation on every n-th window only and 
+    %   repeat your previous feedback for all other windows.
+    global CounterRS
+    global DataRS 
+    global RestValue
+    global Correction
+    global Filter
+
+    % CONSTANTS
+    EXPECTED_AMPLITUDE =  0.1;
+    EXPECTED_MIN_DIFF  = -0.4;
+    EXPECTED_MAX_DIFF  =  0.4;
+    
+    r    = 0.5;   % default return
+    tick = tic(); % start time of execution
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    if marker == 2
+        %% RESTING PHASE
+        
+        % reset on switch
+        if prevmarker ~= 2
+           CounterRS = 0;
+           DataRS = [];
+        end
+
+        % saving the HbO values of the last sample   
+        CounterRS = CounterRS + 1;
+        DataRS(CounterRS,:) = window.HbO(end,:);
+        %disp(CounterRS)
+
+        % 5 frames before 30 seconds of rest (to avoid final delays)
+        if CounterRS == floor(samplerate*30)-5
+            %% CALCULATE CORRECTION FACTOR USING AMPLITUDE
+            % (1) Extract last ~15s of HbO channels of resting phase
+            % (2) Filter each HbO channel
+            % (3) Create average HbO channel from all filtered HbO channels
+            % (4) Sort average HbO channel
+            % (5) Calculate amplitude using mean of highest and lowest
+            filtered = DataRS(floor(samplerate*15):end,:);
+            for ch = 1:size(filtered,2) 
+                filtered(:,ch) = conv(filtered(:,ch), Filter, 'same'); 
+            end
+            mean_hbo   = mean(filtered,2);
+            mean_hbo   = sort(mean_hbo);
+            mean_top25 = mean(mean_hbo(end-35:end-10));
+            mean_low25 = mean(mean_hbo(10:35));
+            amplitude  = abs(mean_top25 - mean_low25);
+            Correction = EXPECTED_AMPLITUDE / amplitude;
+            %disp("Amplitude:  " + sprintf('%.3f', amplitude));
+            %disp("Correction: " + sprintf('%.3f', Correction));
+
+            %% AVERAGE OF HBO OF LAST ~5S OF RESTING PHASE
+            DataFilt = DataRS(floor(samplerate*25):end,:);
+            for ch = 1:size(DataFilt,2) 
+                DataFilt(:,ch) = conv(DataFilt(:,ch), Filter, 'same'); 
+            end
+            RestValue = mean(mean(DataFilt,2));
+            %disp("Rest Average: " + sprintf('%.3f', RestValue));
+        end
+
+    elseif marker == 3
+        %% CONCENTRATION PHASE
+
+        % filter each HbO channel in current sliding window
+        for ch = 1:size(window.HbO,2)
+            DataFilt(:,ch) = conv(window.HbO(:,ch), Filter, 'same'); 
+        end
+
+        % calculate mean HbO channel and mean HbO over time
+        mean_hbo = mean(mean(DataFilt,1));
+
+        % feedback is difference in HbO scaled by correction
+        feedback = mean_hbo - RestValue;
+        feedback = feedback * Correction;
+        
+        % convert from expected range to [0,1] using
+        % r = (((X-a)*(d-c)) / (b-a)) + c 
+        % (a, b) = initial interval 
+        % (c, d) = final interval
+        r = (((feedback-EXPECTED_MIN_DIFF)*(1.0-0.0)) / ...
+            (EXPECTED_MAX_DIFF-EXPECTED_MIN_DIFF)) + 0.0;
+    end
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    % time spent
+    span = toc(tick);
+    
+    % create debug output
+    output = ...
+        "| sample="   + sprintf('%05d', samplenum) + " " + ...
+        "| window="   + sprintf('%05d', windownum) + " " + ...
+        "| marker="   + sprintf('%02d', marker)    + " " + ...
+        "| duration=" + sprintf('%.3f', span)+"s"  + " " + ...
+        "| feedback=" + sprintf('%.3f', r)         + " ";
+    
+    % add values for marker=3
+    if marker == 3
+        output = output + ...
+            "| restavg="    + sprintf('%.3f', RestValue)  + " " + ...
+            "| wndavg="     + sprintf('%.3f', mean_hbo)   + " " + ...
+            "| correction=" + sprintf('%.3f', Correction) + " ";
+    end
+    
+    % show debug output
+    disp(output + "|");
+end
+
+% EXECUTED AT THE END OF THE SESSION
+function finish(session)
+    ploth = figure('Name', 'Session Plot');
+    ploth.NumberTitle = 'off';
+    
+    nplot  = 1; % Current one
+    nplots = 3; % HbO, Feedback, Marker
+    if isfield(session.data, "HbR")
+        nplots = 4; % + HbR
+    end
+    
+    % Plotting unfiltered HbO mean channel
+    subplot(nplots,1,nplot);
+    plot(mean(session.data.HbO,2),'r');
+    title('HbO [μmol/L]');
+    
+    % Plotting unfiltered HbR mean channel (optional)
+    if isfield(session.data, "HbR")
+        nplot  = nplot + 1;
+        subplot(nplots,1,nplot);
+        plot(mean(session.data.HbR,2),'b');
+        title('HbR [μmol/L]');
+    end
+
+    % Plotting Feedback values
+    nplot = nplot + 1;
+    subplot(nplots,1,nplot);
+    plot(session.feedback(:,1));
+    title('Feedback');
+    
+    % Plotting Marker Values
+    nplot = nplot + 1;
+    subplot(nplots,1,nplot);
+    plot(session.markers(:,1));
+    title('Marker');
+end
diff --git a/protocols/RecordOnly.m b/protocols/RecordOnly.m
new file mode 100644
index 0000000..7116cbe
--- /dev/null
+++ b/protocols/RecordOnly.m
@@ -0,0 +1,52 @@
+function fh = RecordOnly
+  fh.requires = @requires;
+  fh.init     = @init;
+  fh.process  = @process;
+  fh.finish   = @finish;
+end
+
+% REQUIREMENTS FOR PROTOCOL
+function r = requires()
+    r.devicetype  = "ANY";
+    r.window.mins = 1.0;
+    r.window.maxs = 300.0;
+    r.channels    = struct([]);
+end
+
+% EXECUTED ONCE ON START
+function init()
+end
+
+% EXECUTED FOR EACH SLIDING WINDOW
+function r = process(~, ~, ~, ~, ~, ~, ~, ~, ~)
+    r = 0.0;
+end
+
+% EXECUTED AT THE END OF THE SESSION
+function finish(session)
+    ploth = figure('Name', 'Session Plot');
+    ploth.NumberTitle = 'off';
+    nchannels = length(session.channels);
+    nplots = nchannels+2;
+    
+    iplots = 1;
+    fn = fieldnames(session.data); %TODO: Cache this
+    for k = 1:numel(fn)
+        for i = 1:size(session.data.(fn{k}), 2)
+            subplot(nplots,1,iplots);
+            plot(session.data.(fn{k})(:,i));
+            title('Channel');
+            iplots = iplots + 1;
+        end
+
+    end
+    
+    % Plotting Feedback values
+    subplot(nplots,1,nchannels+1);
+    plot(session.feedback(:,1));
+    title('Feedback');
+    % Plotting Marker Values
+    subplot(nplots,1,nchannels+2);
+    plot(session.markers(:,1));
+    title('Marker');
+end
diff --git a/protocols/example1.m b/protocols/example1.m
deleted file mode 100644
index 91825b8..0000000
--- a/protocols/example1.m
+++ /dev/null
@@ -1,57 +0,0 @@
-% Example Algorithm 1 for Demonstration
-%   marker:       current epoch marker
-%   samplerate:   sample rate
-%   samplenum:    current sample number
-%   sample:       current sample values
-%   windownum:    current window number
-%   window:       current window values
-%   isfullwindow: true once first window is filled
-%   prevfeedback: previous feedback
-%   RETURN:       normalized value between 0.0 (min) and 1.0 (max)
-
-function r = example1(...
-    marker, samplerate, samplenum, sample, ...
-    windownum, window, isfullwindow, prevfeedback)
-
-    % IMPORTANT: 
-    %   Your algorithm must take less than (1/samplerate) seconds 
-    %   in average or else you fall behind schedule and get a drift.
-    %   If you're algorithm requires more time than that then
-    %   run your calculation on every n-th window only and 
-    %   repeat your previous feedback for all other windows.
-
-    n    = 1;
-    tick = tic();
-    
-    % custom feedback range
-    minfb = -100;
-    maxfb = 100;
-    
-    % return 0.5 until first full window
-    if ~isfullwindow
-        r = 0.5;
-    
-    % calculate on every n-th window
-    elseif mod(windownum, n) == 0
-        % simulate 80% computation time (80ms of 100ms for 10Hz)
-        pause((1.0/double(samplerate))*0.8);
-        % create dummy feedback value in [minfb, maxfb]
-        r = double(randi([minfb,maxfb]));
-        % map from [minfb, maxfb] to [0, 1]    
-        r = (r-minfb) * (1.0/(maxfb-minfb));
-        
-    % skip this sample/window
-    else
-        r = prevfeedback;
-    end
-
-    % time spent
-    span = toc(tick);
-
-    % debug
-    disp("Processed sample " + samplenum + ...
-        " (window=" + windownum + ...
-        ", marker=" + marker + ...
-        ", duration=" + sprintf('%.3f', span) + "s" + ...
-        ", fb=" + sprintf('%.3f', r) + ")");
-end
diff --git a/settings/Gauss.mat b/settings/Gauss.mat
new file mode 100644
index 0000000..6433732
Binary files /dev/null and b/settings/Gauss.mat differ
diff --git a/ui/app.mlapp b/ui/app.mlapp
index 972f3fa..1f32e22 100644
Binary files a/ui/app.mlapp and b/ui/app.mlapp differ
diff --git a/ui/app_exported.m b/ui/app_exported.m
index dd08084..5be1d43 100644
--- a/ui/app_exported.m
+++ b/ui/app_exported.m
@@ -2,63 +2,69 @@
 
     % Properties that correspond to app components
     properties (Access = public)
-        UIFigure                        matlab.ui.Figure
-        FileMenu                        matlab.ui.container.Menu
-        LoadMenu                        matlab.ui.container.Menu
-        SaveMenu                        matlab.ui.container.Menu
-        LSLSTREAMPanel                  matlab.ui.container.Panel
-        GridLayout                      matlab.ui.container.GridLayout
-        TYPELabel                       matlab.ui.control.Label
-        TYPEEditField                   matlab.ui.control.EditField
-        OPENButton                      matlab.ui.control.Button
-        CHANNELSLabel_2                 matlab.ui.control.Label
-        CHANNELSFOUNDLabel              matlab.ui.control.Label
-        SAMPLERATEDescLabel             matlab.ui.control.Label
-        SAMPLERATELabel                 matlab.ui.control.Label
-        SETTINGSPanel                   matlab.ui.container.Panel
-        GridLayout2                     matlab.ui.container.GridLayout
-        SELECTEDCHANNELSEditFieldLabel  matlab.ui.control.Label
-        SELECTEDCHANNELSEditField       matlab.ui.control.EditField
-        WINDOWSIZESEditFieldLabel       matlab.ui.control.Label
-        WINDOWSIZESEditField            matlab.ui.control.NumericEditField
-        SESSIONLENGTHSEditFieldLabel    matlab.ui.control.Label
-        SESSIONLENGTHSEditField         matlab.ui.control.NumericEditField
-        PROTOCOLLabel                   matlab.ui.control.Label
-        PROTOCOLDropDown                matlab.ui.control.DropDown
-        STARTButton                     matlab.ui.control.Button
-        SESSIONINFOPanel                matlab.ui.container.Panel
-        GridLayout3                     matlab.ui.container.GridLayout
-        SESSIONSTARTEDDescLabel         matlab.ui.control.Label
-        SESSIONSTARTEDLabel             matlab.ui.control.Label
-        SESSIONENDEDDescLabel           matlab.ui.control.Label
-        SESSIONENDEDLabel               matlab.ui.control.Label
-        SESSIONLENGTHSDescLabel         matlab.ui.control.Label
-        SESSIONLENGTHLabel              matlab.ui.control.Label
-        SESSIONSAMPLESLabel             matlab.ui.control.Label
-        SESSIONDRIFTLabel               matlab.ui.control.Label
-        SESSIONSAMPLESDescLabel         matlab.ui.control.Label
-        SESSIONDRIFTDescLabel           matlab.ui.control.Label
-        SESSSIONSTATUSDescLabel         matlab.ui.control.Label
-        SESSIONSTATUSLabel              matlab.ui.control.Label
-        EPOCHSPanel                     matlab.ui.container.Panel
-        MARKERTable                     matlab.ui.control.Table
-        MARKERAddButton                 matlab.ui.control.Button
-        MARKERDelButton                 matlab.ui.control.Button
-        COLORButton                     matlab.ui.control.Button
-        IDPanel                         matlab.ui.container.Panel
-        GridLayout4                     matlab.ui.container.GridLayout
-        SUBJECTEditFieldLabel           matlab.ui.control.Label
-        SUBJECTEditField                matlab.ui.control.NumericEditField
-        RUNEditFieldLabel               matlab.ui.control.Label
-        RUNEditField                    matlab.ui.control.NumericEditField
-        STUDYEditFieldLabel             matlab.ui.control.Label
-        STUDYEditField                  matlab.ui.control.EditField
-        PROTOCOLTIMEPanel               matlab.ui.container.Panel
-        GridLayout5                     matlab.ui.container.GridLayout
-        PROTOCOLMaxLabel                matlab.ui.control.Label
-        PROTOCOLMaxDescLabel            matlab.ui.control.Label
-        PROTOCOLAvgLabel                matlab.ui.control.Label
-        PROTOCOLAvgDescLabel            matlab.ui.control.Label
+        UIFigure                      matlab.ui.Figure
+        FileMenu                      matlab.ui.container.Menu
+        LoadMenu                      matlab.ui.container.Menu
+        SaveMenu                      matlab.ui.container.Menu
+        LSLSTREAMPanel                matlab.ui.container.Panel
+        GridLayout                    matlab.ui.container.GridLayout
+        TYPELabel                     matlab.ui.control.Label
+        TYPEEditField                 matlab.ui.control.EditField
+        OPENButton                    matlab.ui.control.Button
+        CHANNELSLabel_2               matlab.ui.control.Label
+        CHANNELSFOUNDLabel            matlab.ui.control.Label
+        SAMPLERATEDescLabel           matlab.ui.control.Label
+        SAMPLERATELabel               matlab.ui.control.Label
+        SETTINGSPanel                 matlab.ui.container.Panel
+        GridLayout2                   matlab.ui.container.GridLayout
+        WINDOWSIZESEditFieldLabel     matlab.ui.control.Label
+        WINDOWSIZESEditField          matlab.ui.control.NumericEditField
+        SESSIONLENGTHSEditFieldLabel  matlab.ui.control.Label
+        SESSIONLENGTHSEditField       matlab.ui.control.NumericEditField
+        PROTOCOLLabel                 matlab.ui.control.Label
+        PROTOCOLDropDown              matlab.ui.control.DropDown
+        CHANNELSButton                matlab.ui.control.Button
+        CHANNELSLabel_3               matlab.ui.control.Label
+        STARTButton                   matlab.ui.control.Button
+        SESSIONINFOPanel              matlab.ui.container.Panel
+        GridLayout3                   matlab.ui.container.GridLayout
+        SESSIONSTARTEDDescLabel       matlab.ui.control.Label
+        SESSIONSTARTEDLabel           matlab.ui.control.Label
+        SESSIONENDEDDescLabel         matlab.ui.control.Label
+        SESSIONENDEDLabel             matlab.ui.control.Label
+        SESSIONLENGTHSDescLabel       matlab.ui.control.Label
+        SESSIONLENGTHLabel            matlab.ui.control.Label
+        SESSIONSAMPLESLabel           matlab.ui.control.Label
+        SESSIONDRIFTLabel             matlab.ui.control.Label
+        SESSIONSAMPLESDescLabel       matlab.ui.control.Label
+        SESSIONDRIFTDescLabel         matlab.ui.control.Label
+        SESSSIONSTATUSDescLabel       matlab.ui.control.Label
+        SESSIONSTATUSLabel            matlab.ui.control.Label
+        EPOCHSPanel                   matlab.ui.container.Panel
+        MARKERTable                   matlab.ui.control.Table
+        MARKERAddButton               matlab.ui.control.Button
+        MARKERDelButton               matlab.ui.control.Button
+        COLORButton                   matlab.ui.control.Button
+        IDPanel                       matlab.ui.container.Panel
+        GridLayout4                   matlab.ui.container.GridLayout
+        SUBJECTEditFieldLabel         matlab.ui.control.Label
+        SUBJECTEditField              matlab.ui.control.NumericEditField
+        RUNEditFieldLabel             matlab.ui.control.Label
+        RUNEditField                  matlab.ui.control.NumericEditField
+        STUDYEditFieldLabel           matlab.ui.control.Label
+        STUDYEditField                matlab.ui.control.EditField
+        PROTOCOLTIMEPanel             matlab.ui.container.Panel
+        GridLayout5                   matlab.ui.container.GridLayout
+        PROTOCOLMaxLabel              matlab.ui.control.Label
+        PROTOCOLMaxDescLabel          matlab.ui.control.Label
+        PROTOCOLAvgLabel              matlab.ui.control.Label
+        PROTOCOLAvgDescLabel          matlab.ui.control.Label
+        DEVICEPanel                   matlab.ui.container.Panel
+        GridLayout6                   matlab.ui.container.GridLayout
+        MODELDropDownLabel            matlab.ui.control.Label
+        DEVICEDropDown                matlab.ui.control.DropDown
+        TYPEDropDownLabel             matlab.ui.control.Label
+        TYPEDropDown                  matlab.ui.control.DropDown
     end
 
     
@@ -77,10 +83,10 @@ function onSessionStarted(app, src, ~)
             app.STARTButton.Text = "STOP";
             app.LoadMenu.Enable = false;
             app.SaveMenu.Enable = false;
-            app.SELECTEDCHANNELSEditField.Enable = false;
             app.WINDOWSIZESEditField.Enable = false;
             app.SESSIONLENGTHSEditField.Enable = false;
             app.PROTOCOLDropDown.Enable = false;         
+            app.CHANNELSButton.Enable = false;
             app.SUBJECTEditField.Enable = false;
             app.RUNEditField.Enable = false;
             app.STUDYEditField.Enable = false;          
@@ -99,10 +105,10 @@ function onSessionStopped(app, src, ~)
             app.STARTButton.Text = "START";
             app.LoadMenu.Enable = true;
             app.SaveMenu.Enable = true;
-            app.SELECTEDCHANNELSEditField.Enable = true;
             app.WINDOWSIZESEditField.Enable = true;
             app.SESSIONLENGTHSEditField.Enable = true;
             app.PROTOCOLDropDown.Enable = true;
+            app.CHANNELSButton.Enable = true;
             app.SUBJECTEditField.Enable = true;
             app.RUNEditField.Enable = true;
             app.STUDYEditField.Enable = true;
@@ -119,6 +125,9 @@ function onSessionStopped(app, src, ~)
             app.updateStatus();
         end
 
+        function onChannelsSelected(app, ~, ~)
+            app.updateStartButton();
+        end
     end
     
     methods (Access = public)
@@ -147,7 +156,7 @@ function updateStatus(app)
                 sprintf('%.2f', mysession.length) + " s";
             app.SESSIONSAMPLESLabel.Text = ...
                 string(mysession.idx) + "/" + ...
-                string(length(mysession.data));
+                string(mysession.datasize);
             app.SESSIONDRIFTLabel.Text = ...
                 sprintf('%.2f', drift) + " s";
             if drift > 1.0 || drift < -1.0
@@ -165,7 +174,7 @@ function updateStatus(app)
                 app.PROTOCOLAvgLabel.BackgroundColor = 'green';
             end
         end
-        
+
         function update(app)
             global mylsl
             global mysession
@@ -189,6 +198,76 @@ function update(app)
                 app.updateStatus();
             end
         end
+        
+        function updateStartButton(app)
+            global myselectchannels
+            global mylsl
+            if ~mylsl.streaming
+                app.STARTButton.Text = "CONNECT LSL FIRST";
+                app.STARTButton.Enable = false;
+            elseif ~myselectchannels.isok
+                app.STARTButton.Text = "SELECT CHANNELS FIRST";
+                app.STARTButton.Enable = false;
+            else
+                app.STARTButton.Text = "START";
+                app.STARTButton.Enable = true;
+            end
+        end
+        
+        function updateDevices(app)
+            global mydevices;
+            app.DEVICEDropDown.Items = {};
+            type = lower(app.TYPEDropDown.Value);
+            for idx = 1:length(mydevices.(type))
+                app.DEVICEDropDown.Items(idx) = ...
+                    cellstr(mydevices.(type)(idx).name);
+            end
+        end
+        
+        function useDevice(app)
+            global mydevices;
+            global myprotocols;
+            type = convertCharsToStrings(app.TYPEDropDown.Value);
+            name = convertCharsToStrings(app.DEVICEDropDown.Value);
+            if mydevices.select(type, name)
+                disp("SELECTED DEVICE: " + mydevices.selected.name + ...
+                    "(" + mydevices.selected.type + ")");
+                app.TYPEEditField.Value = mydevices.selected.lsl.type;
+                myprotocols.reload(mydevices.selected);
+                app.PROTOCOLDropDown.Items = {};
+                for idx = 1:length(myprotocols.list)
+                    app.PROTOCOLDropDown.Items(idx) = ...
+                        cellstr(myprotocols.list(idx).name);
+                end
+                app.useProtocol();
+            end
+        end
+        
+        function useProtocol(app)
+            global myprotocols;
+            global myselectchannels;
+            name = convertCharsToStrings(app.PROTOCOLDropDown.Value);
+            if myprotocols.select(name)
+                disp("SELECTED PROTOCOL: " + myprotocols.selected.name)
+                myselectchannels.selected = [];
+                myselectchannels.initRequired();
+                myselectchannels.initSelected();
+            end
+            app.checkWindowSize();
+            app.updateStartButton();
+        end
+        
+        function checkWindowSize(app)
+            global myprotocols
+            v = app.WINDOWSIZESEditField.Value;
+            if ~isempty(myprotocols.selected)
+                r = myprotocols.selected.fh.requires();
+                v = min(max(v, r.window.mins), r.window.maxs);
+            end
+            if app.WINDOWSIZESEditField.Value ~= v
+                app.WINDOWSIZESEditField.Value = v;
+            end
+        end
     end
     
 
@@ -198,10 +277,16 @@ function update(app)
         % Code that executes after component creation
         function startupFcn(app)
             global mysession;
-            app.UIFigure.Name = "Settings";
+            global myselectchannels;
+            app.UIFigure.Name = "NINFA v1.1.0";
             addlistener(mysession, "Started", @app.onSessionStarted);
             addlistener(mysession, "Stopped", @app.onSessionStopped);
-            app.PROTOCOLDropDown.Items = string(ls("protocols/*.m"));
+            addlistener(myselectchannels, "Done", @app.onChannelsSelected);
+            for idx = 1:length(devices.types)
+                app.TYPEDropDown.Items(idx) = cellstr(devices.types(idx));
+            end
+            app.updateDevices();
+            app.useDevice();
             app.MARKERTable.SelectionType = 'row';
             app.MARKERTable.ColumnFormat = { 
                 'short', 'short', 'short', 'logical', 'short', 'short', 'short' };
@@ -210,27 +295,29 @@ function startupFcn(app)
         % Button pushed function: OPENButton
         function OPENButtonPushed(app, event)
             global mylsl
+            global myselectchannels
             if ~mylsl.streaming
                 r = mylsl.open(app.TYPEEditField.Value);
                 if r
                     app.tick = tic();
                     app.OPENButton.Text = "CLOSE";
+                    app.TYPEDropDown.Enable = false;
+                    app.DEVICEDropDown.Enable = false;
                     app.TYPEEditField.Enable = false;
                     app.CHANNELSFOUNDLabel.Text = int2str(mylsl.lslchannels);
-                    app.SELECTEDCHANNELSEditField.Enable = true;
                     app.WINDOWSIZESEditField.Enable = true;
                     app.SESSIONLENGTHSEditField.Enable = true;
                     app.PROTOCOLDropDown.Enable = true;               
                     app.SUBJECTEditField.Enable = true;
                     app.RUNEditField.Enable = true;
-                    app.STUDYEditField.Enable = true;                 
+                    app.STUDYEditField.Enable = true;
+                    app.CHANNELSButton.Enable = true;
                     app.MARKERTable.Enable = 'on';
                     app.MARKERAddButton.Enable = true;
                     if size(app.MARKERTable.Data,1) > 0
                         app.MARKERDelButton.Enable = true;
                         app.COLORButton.Enable = true;
                     end
-                    app.STARTButton.Enable = true;
                 else
                     msgbox("No LSL stream with type '" + ...
                         app.TYPEEditField.Value + ...
@@ -238,33 +325,38 @@ function OPENButtonPushed(app, event)
                 end
             else
                 mylsl.close();
+                myselectchannels.close();
                 app.OPENButton.Text = "OPEN";
                 app.CHANNELSFOUNDLabel.Text = "-";
                 app.SAMPLERATELabel.Text = "-";
+                app.TYPEDropDown.Enable = true;
+                app.DEVICEDropDown.Enable = true;
                 app.TYPEEditField.Enable = true;
-                app.SELECTEDCHANNELSEditField.Enable = false;
                 app.WINDOWSIZESEditField.Enable = false;
                 app.SESSIONLENGTHSEditField.Enable = false;
                 app.PROTOCOLDropDown.Enable = false;
                 app.SUBJECTEditField.Enable = false;
                 app.RUNEditField.Enable = false;
                 app.STUDYEditField.Enable = false;
+                app.CHANNELSButton.Enable = false;
                 app.MARKERTable.Enable = 'off';
                 app.MARKERAddButton.Enable = false;
                 app.MARKERDelButton.Enable = false;
                 app.COLORButton.Enable = false;
-                app.STARTButton.Enable = false;
                 app.SAMPLERATELabel.BackgroundColor = 'none';
             end
+            app.updateStartButton();
         end
 
         % Button pushed function: STARTButton
         function STARTButtonPushed(app, event)
             global mylsl;
             global mysession;
+            global myselectchannels;
+            global mydevices;
             if ~mysession.running
-                strchannels = split(app.SELECTEDCHANNELSEditField.Value, ',');
-                channels = transpose(str2double(strchannels));
+                channels = myselectchannels.selected;
+                device = mydevices.selected;
                 srate = mylsl.sratenom; % prefer claimed samplerate
                 if srate <= 0, srate = mylsl.srate; end % else use measured
                 blocksize = app.WINDOWSIZESEditField.Value * srate;
@@ -274,6 +366,7 @@ function STARTButtonPushed(app, event)
                     app.SESSIONLENGTHSEditField.Value, ...
                     app.WINDOWSIZESEditField.Value, ...
                     srate, ...
+                    device, ...
                     channels, ...
                     app.MARKERTable.Data, ...
                     app.STUDYEditField.Value, ...
@@ -285,26 +378,6 @@ function STARTButtonPushed(app, event)
 
         end
 
-        % Value changed function: SELECTEDCHANNELSEditField
-        function SELECTEDCHANNELSEditFieldValueChanged(app, event)
-            global mylsl;
-            newvalue = "";
-            values = split(app.SELECTEDCHANNELSEditField.Value, ',');
-            for k = 1:length(values)
-                v = values{k};
-                v = strip(v, ' ');
-                [x, s] = str2num(v);
-                if s && x > 0 && x <= mylsl.lslchannels
-                    newvalue = newvalue + x + ',';
-                end
-            end
-            newvalue = strip(newvalue, ',');
-            if newvalue == ""
-                newvalue = "1";
-            end
-            app.SELECTEDCHANNELSEditField.Value = newvalue;
-        end
-
         % Button pushed function: MARKERAddButton
         function MARKERAddButtonPushed(app, event)
             app.MARKERTable.Data = [app.MARKERTable.Data;[0 0 1 1 0 0 0]];
@@ -336,6 +409,7 @@ function MARKERDelButtonPushed(app, event)
         % Menu selected function: LoadMenu
         function LoadMenuSelected(app, event)
             global mylsl;
+            global myselectchannels;
             [file, path] = uigetfile("./settings/*.mat");
             figure(app.UIFigure); % focus back
             filepath = string(path) + string(file);
@@ -343,11 +417,24 @@ function LoadMenuSelected(app, event)
                 return;
             end
             settings = load(filepath);           
+            if isfield(settings, 'devicetype')
+                app.TYPEDropDown.Value = settings.devicetype;
+                app.updateDevices();
+            end
+            if isfield(settings, 'devicename')
+                if any(strcmp(app.DEVICEDropDown.Items, settings.devicename))
+                    app.DEVICEDropDown.Value = settings.devicename;
+                    app.useDevice();
+                else
+                    msgbox("Device '" + settings.devicename + ...
+                    "' was not found on this computer", "Warning", "warn");
+                end
+            end
             if isfield(settings, 'lsltype')
                 app.TYPEEditField.Value = settings.lsltype;
             end
             if isfield(settings, 'channels')
-                app.SELECTEDCHANNELSEditField.Value = settings.channels;
+                myselectchannels.selected = settings.channels;              
             end
             if isfield(settings, 'windowsize')
                 app.WINDOWSIZESEditField.Value = settings.windowsize;
@@ -358,6 +445,7 @@ function LoadMenuSelected(app, event)
             if isfield(settings, 'protocol')
                 if any(strcmp(app.PROTOCOLDropDown.Items, settings.protocol))
                     app.PROTOCOLDropDown.Value = settings.protocol;
+                    app.useProtocol();
                 else
                     msgbox("Protocol '" + settings.protocol + ...
                     "' was not found on this computer", "Warning", "warn");
@@ -383,14 +471,18 @@ function LoadMenuSelected(app, event)
 
         % Menu selected function: SaveMenu
         function SaveMenuSelected(app, event)
+            global mydevices;
+            global myselectchannels;
             [file, path] = uiputfile("./settings/*.mat");
             figure(app.UIFigure); % focus back
             if isequal(file,0) || isequal(path,0)
                 return;
             end
             filepath = string(path) + string(file);
+            settings.devicetype = mydevices.selected.type;
+            settings.devicename = mydevices.selected.name;
             settings.lsltype = app.TYPEEditField.Value;
-            settings.channels = app.SELECTEDCHANNELSEditField.Value;
+            settings.channels = myselectchannels.selected;
             settings.windowsize = app.WINDOWSIZESEditField.Value;
             settings.sessionlength = app.SESSIONLENGTHSEditField.Value;
             settings.protocol = app.PROTOCOLDropDown.Value;
@@ -429,6 +521,35 @@ function COLORButtonPushed(app, event)
             end           
             app.updateColors();
         end
+
+        % Value changed function: DEVICEDropDown
+        function DEVICEDropDownValueChanged(app, event)
+            app.useDevice();
+        end
+
+        % Value changed function: TYPEDropDown
+        function TYPEDropDownValueChanged(app, event)
+            app.updateDevices();
+            app.useDevice();
+        end
+
+        % Button pushed function: CHANNELSButton
+        function CHANNELSButtonPushed(app, event)
+            global myselectchannels;
+            myselectchannels.show();
+            %myselectchannels.initRequired();
+            %myselectchannels.initSelected();
+        end
+
+        % Value changed function: PROTOCOLDropDown
+        function PROTOCOLDropDownValueChanged(app, event)
+            app.useProtocol();
+        end
+
+        % Value changed function: WINDOWSIZESEditField
+        function WINDOWSIZESEditFieldValueChanged(app, event)
+            app.checkWindowSize();
+        end
     end
 
     % Component initialization
@@ -440,7 +561,7 @@ function createComponents(app)
             % Create UIFigure and hide until all components are created
             app.UIFigure = uifigure('Visible', 'off');
             app.UIFigure.AutoResizeChildren = 'off';
-            app.UIFigure.Position = [100 100 653 680];
+            app.UIFigure.Position = [100 100 640 772];
             app.UIFigure.Name = 'MATLAB App';
             app.UIFigure.Resize = 'off';
 
@@ -462,11 +583,11 @@ function createComponents(app)
             app.LSLSTREAMPanel = uipanel(app.UIFigure);
             app.LSLSTREAMPanel.AutoResizeChildren = 'off';
             app.LSLSTREAMPanel.Title = 'LSL STREAM';
-            app.LSLSTREAMPanel.Position = [16 510 625 156];
+            app.LSLSTREAMPanel.Position = [16 541 608 118];
 
             % Create GridLayout
             app.GridLayout = uigridlayout(app.LSLSTREAMPanel);
-            app.GridLayout.ColumnWidth = {'1.5x', '2x', '1x'};
+            app.GridLayout.ColumnWidth = {'1.32x', '2x', '1x'};
             app.GridLayout.RowHeight = {'1x', '1x', '1x'};
 
             % Create TYPELabel
@@ -480,7 +601,6 @@ function createComponents(app)
             app.TYPEEditField = uieditfield(app.GridLayout, 'text');
             app.TYPEEditField.Layout.Row = 1;
             app.TYPEEditField.Layout.Column = 2;
-            app.TYPEEditField.Value = 'NIRS';
 
             % Create OPENButton
             app.OPENButton = uibutton(app.GridLayout, 'push');
@@ -519,48 +639,35 @@ function createComponents(app)
             app.SETTINGSPanel = uipanel(app.UIFigure);
             app.SETTINGSPanel.AutoResizeChildren = 'off';
             app.SETTINGSPanel.Title = 'SETTINGS';
-            app.SETTINGSPanel.Position = [16 340 375 157];
+            app.SETTINGSPanel.Position = [16 363 375 165];
 
             % Create GridLayout2
             app.GridLayout2 = uigridlayout(app.SETTINGSPanel);
             app.GridLayout2.RowHeight = {'1x', '1x', '1x', '1x'};
 
-            % Create SELECTEDCHANNELSEditFieldLabel
-            app.SELECTEDCHANNELSEditFieldLabel = uilabel(app.GridLayout2);
-            app.SELECTEDCHANNELSEditFieldLabel.HorizontalAlignment = 'center';
-            app.SELECTEDCHANNELSEditFieldLabel.Layout.Row = 1;
-            app.SELECTEDCHANNELSEditFieldLabel.Layout.Column = 1;
-            app.SELECTEDCHANNELSEditFieldLabel.Text = 'SELECTED CHANNELS';
-
-            % Create SELECTEDCHANNELSEditField
-            app.SELECTEDCHANNELSEditField = uieditfield(app.GridLayout2, 'text');
-            app.SELECTEDCHANNELSEditField.ValueChangedFcn = createCallbackFcn(app, @SELECTEDCHANNELSEditFieldValueChanged, true);
-            app.SELECTEDCHANNELSEditField.Enable = 'off';
-            app.SELECTEDCHANNELSEditField.Tooltip = {'Enter comma separated numeric values larger than zero and less or equal to LSL channels.'};
-            app.SELECTEDCHANNELSEditField.Layout.Row = 1;
-            app.SELECTEDCHANNELSEditField.Layout.Column = 2;
-            app.SELECTEDCHANNELSEditField.Value = '2';
-
             % Create WINDOWSIZESEditFieldLabel
             app.WINDOWSIZESEditFieldLabel = uilabel(app.GridLayout2);
             app.WINDOWSIZESEditFieldLabel.HorizontalAlignment = 'center';
-            app.WINDOWSIZESEditFieldLabel.Layout.Row = 2;
+            app.WINDOWSIZESEditFieldLabel.FontSize = 11;
+            app.WINDOWSIZESEditFieldLabel.Layout.Row = 3;
             app.WINDOWSIZESEditFieldLabel.Layout.Column = 1;
             app.WINDOWSIZESEditFieldLabel.Text = 'WINDOW SIZE (S)';
 
             % Create WINDOWSIZESEditField
             app.WINDOWSIZESEditField = uieditfield(app.GridLayout2, 'numeric');
             app.WINDOWSIZESEditField.Limits = [0 3600];
+            app.WINDOWSIZESEditField.ValueChangedFcn = createCallbackFcn(app, @WINDOWSIZESEditFieldValueChanged, true);
             app.WINDOWSIZESEditField.HorizontalAlignment = 'left';
             app.WINDOWSIZESEditField.Enable = 'off';
-            app.WINDOWSIZESEditField.Layout.Row = 2;
+            app.WINDOWSIZESEditField.Layout.Row = 3;
             app.WINDOWSIZESEditField.Layout.Column = 2;
-            app.WINDOWSIZESEditField.Value = 2;
+            app.WINDOWSIZESEditField.Value = 1;
 
             % Create SESSIONLENGTHSEditFieldLabel
             app.SESSIONLENGTHSEditFieldLabel = uilabel(app.GridLayout2);
             app.SESSIONLENGTHSEditFieldLabel.HorizontalAlignment = 'center';
-            app.SESSIONLENGTHSEditFieldLabel.Layout.Row = 3;
+            app.SESSIONLENGTHSEditFieldLabel.FontSize = 11;
+            app.SESSIONLENGTHSEditFieldLabel.Layout.Row = 4;
             app.SESSIONLENGTHSEditFieldLabel.Layout.Column = 1;
             app.SESSIONLENGTHSEditFieldLabel.Text = 'SESSION LENGTH (S)';
 
@@ -569,43 +676,60 @@ function createComponents(app)
             app.SESSIONLENGTHSEditField.Limits = [0 3600];
             app.SESSIONLENGTHSEditField.HorizontalAlignment = 'left';
             app.SESSIONLENGTHSEditField.Enable = 'off';
-            app.SESSIONLENGTHSEditField.Layout.Row = 3;
+            app.SESSIONLENGTHSEditField.Layout.Row = 4;
             app.SESSIONLENGTHSEditField.Layout.Column = 2;
             app.SESSIONLENGTHSEditField.Value = 10;
 
             % Create PROTOCOLLabel
             app.PROTOCOLLabel = uilabel(app.GridLayout2);
             app.PROTOCOLLabel.HorizontalAlignment = 'center';
-            app.PROTOCOLLabel.Layout.Row = 4;
+            app.PROTOCOLLabel.FontSize = 11;
+            app.PROTOCOLLabel.Layout.Row = 1;
             app.PROTOCOLLabel.Layout.Column = 1;
             app.PROTOCOLLabel.Text = 'PROTOCOL';
 
             % Create PROTOCOLDropDown
             app.PROTOCOLDropDown = uidropdown(app.GridLayout2);
             app.PROTOCOLDropDown.Items = {};
+            app.PROTOCOLDropDown.ValueChangedFcn = createCallbackFcn(app, @PROTOCOLDropDownValueChanged, true);
             app.PROTOCOLDropDown.Enable = 'off';
             app.PROTOCOLDropDown.Tooltip = {'Select the Matlab file that should be executed on each window calculating the next feedback. '};
-            app.PROTOCOLDropDown.Layout.Row = 4;
+            app.PROTOCOLDropDown.Layout.Row = 1;
             app.PROTOCOLDropDown.Layout.Column = 2;
             app.PROTOCOLDropDown.Value = {};
 
+            % Create CHANNELSButton
+            app.CHANNELSButton = uibutton(app.GridLayout2, 'push');
+            app.CHANNELSButton.ButtonPushedFcn = createCallbackFcn(app, @CHANNELSButtonPushed, true);
+            app.CHANNELSButton.Enable = 'off';
+            app.CHANNELSButton.Layout.Row = 2;
+            app.CHANNELSButton.Layout.Column = 2;
+            app.CHANNELSButton.Text = 'SELECT';
+
+            % Create CHANNELSLabel_3
+            app.CHANNELSLabel_3 = uilabel(app.GridLayout2);
+            app.CHANNELSLabel_3.HorizontalAlignment = 'center';
+            app.CHANNELSLabel_3.Layout.Row = 2;
+            app.CHANNELSLabel_3.Layout.Column = 1;
+            app.CHANNELSLabel_3.Text = 'CHANNELS';
+
             % Create STARTButton
             app.STARTButton = uibutton(app.UIFigure, 'push');
             app.STARTButton.ButtonPushedFcn = createCallbackFcn(app, @STARTButtonPushed, true);
             app.STARTButton.Enable = 'off';
             app.STARTButton.Tooltip = {'Start or stop session'};
-            app.STARTButton.Position = [17 13 622 22];
+            app.STARTButton.Position = [16 19 608 22];
             app.STARTButton.Text = 'START';
 
             % Create SESSIONINFOPanel
             app.SESSIONINFOPanel = uipanel(app.UIFigure);
             app.SESSIONINFOPanel.AutoResizeChildren = 'off';
             app.SESSIONINFOPanel.Title = 'SESSION INFO';
-            app.SESSIONINFOPanel.Position = [17 48 473 115];
+            app.SESSIONINFOPanel.Position = [17 56 473 115];
 
             % Create GridLayout3
             app.GridLayout3 = uigridlayout(app.SESSIONINFOPanel);
-            app.GridLayout3.ColumnWidth = {'0.75x', '1x', '0.75x', '1x'};
+            app.GridLayout3.ColumnWidth = {'0.7x', '1x', '0.7x', '1x'};
             app.GridLayout3.RowHeight = {'1x', '1x', '1x'};
 
             % Create SESSIONSTARTEDDescLabel
@@ -693,7 +817,7 @@ function createComponents(app)
             app.EPOCHSPanel = uipanel(app.UIFigure);
             app.EPOCHSPanel.AutoResizeChildren = 'off';
             app.EPOCHSPanel.Title = 'EPOCHS';
-            app.EPOCHSPanel.Position = [16 175 625 157];
+            app.EPOCHSPanel.Position = [16 185 608 162];
 
             % Create MARKERTable
             app.MARKERTable = uitable(app.EPOCHSPanel);
@@ -704,14 +828,14 @@ function createComponents(app)
             app.MARKERTable.CellEditCallback = createCallbackFcn(app, @MARKERTableCellEdit, true);
             app.MARKERTable.Tooltip = {'Define markers (a value between 1 and 99) for epochs here. An epoch is defined by its start and end time. A trigger will be sent at the beginning of each epoch.'};
             app.MARKERTable.Enable = 'off';
-            app.MARKERTable.Position = [11 8 494 120];
+            app.MARKERTable.Position = [11 13 484 120];
 
             % Create MARKERAddButton
             app.MARKERAddButton = uibutton(app.EPOCHSPanel, 'push');
             app.MARKERAddButton.ButtonPushedFcn = createCallbackFcn(app, @MARKERAddButtonPushed, true);
             app.MARKERAddButton.Enable = 'off';
             app.MARKERAddButton.Tooltip = {'Add an epoch'};
-            app.MARKERAddButton.Position = [513 94 100 34];
+            app.MARKERAddButton.Position = [504 99 93 34];
             app.MARKERAddButton.Text = '+';
 
             % Create MARKERDelButton
@@ -719,7 +843,7 @@ function createComponents(app)
             app.MARKERDelButton.ButtonPushedFcn = createCallbackFcn(app, @MARKERDelButtonPushed, true);
             app.MARKERDelButton.Enable = 'off';
             app.MARKERDelButton.Tooltip = {'Remove last or selected epochs'};
-            app.MARKERDelButton.Position = [513 51 100 34];
+            app.MARKERDelButton.Position = [504 56 93 34];
             app.MARKERDelButton.Text = '-';
 
             % Create COLORButton
@@ -727,14 +851,14 @@ function createComponents(app)
             app.COLORButton.ButtonPushedFcn = createCallbackFcn(app, @COLORButtonPushed, true);
             app.COLORButton.Enable = 'off';
             app.COLORButton.Tooltip = {'Select color for selected epochs'};
-            app.COLORButton.Position = [513 8 100 34];
+            app.COLORButton.Position = [504 13 93 34];
             app.COLORButton.Text = 'COLOR';
 
             % Create IDPanel
             app.IDPanel = uipanel(app.UIFigure);
             app.IDPanel.AutoResizeChildren = 'off';
             app.IDPanel.Title = 'ID';
-            app.IDPanel.Position = [400 340 241 157];
+            app.IDPanel.Position = [401 363 223 164];
 
             % Create GridLayout4
             app.GridLayout4 = uigridlayout(app.IDPanel);
@@ -789,7 +913,7 @@ function createComponents(app)
             app.PROTOCOLTIMEPanel = uipanel(app.UIFigure);
             app.PROTOCOLTIMEPanel.AutoResizeChildren = 'off';
             app.PROTOCOLTIMEPanel.Title = 'PROTOCOL TIME';
-            app.PROTOCOLTIMEPanel.Position = [500 48 141 115];
+            app.PROTOCOLTIMEPanel.Position = [495 56 129 115];
 
             % Create GridLayout5
             app.GridLayout5 = uigridlayout(app.PROTOCOLTIMEPanel);
@@ -823,6 +947,46 @@ function createComponents(app)
             app.PROTOCOLAvgDescLabel.Layout.Column = 1;
             app.PROTOCOLAvgDescLabel.Text = 'AVG:';
 
+            % Create DEVICEPanel
+            app.DEVICEPanel = uipanel(app.UIFigure);
+            app.DEVICEPanel.AutoResizeChildren = 'off';
+            app.DEVICEPanel.Title = 'DEVICE';
+            app.DEVICEPanel.Position = [16 673 608 88];
+
+            % Create GridLayout6
+            app.GridLayout6 = uigridlayout(app.DEVICEPanel);
+            app.GridLayout6.ColumnWidth = {'1.32x', '2x', '1x'};
+
+            % Create MODELDropDownLabel
+            app.MODELDropDownLabel = uilabel(app.GridLayout6);
+            app.MODELDropDownLabel.HorizontalAlignment = 'center';
+            app.MODELDropDownLabel.Layout.Row = 2;
+            app.MODELDropDownLabel.Layout.Column = 1;
+            app.MODELDropDownLabel.Text = 'MODEL';
+
+            % Create DEVICEDropDown
+            app.DEVICEDropDown = uidropdown(app.GridLayout6);
+            app.DEVICEDropDown.Items = {};
+            app.DEVICEDropDown.ValueChangedFcn = createCallbackFcn(app, @DEVICEDropDownValueChanged, true);
+            app.DEVICEDropDown.Layout.Row = 2;
+            app.DEVICEDropDown.Layout.Column = 2;
+            app.DEVICEDropDown.Value = {};
+
+            % Create TYPEDropDownLabel
+            app.TYPEDropDownLabel = uilabel(app.GridLayout6);
+            app.TYPEDropDownLabel.HorizontalAlignment = 'center';
+            app.TYPEDropDownLabel.Layout.Row = 1;
+            app.TYPEDropDownLabel.Layout.Column = 1;
+            app.TYPEDropDownLabel.Text = 'TYPE';
+
+            % Create TYPEDropDown
+            app.TYPEDropDown = uidropdown(app.GridLayout6);
+            app.TYPEDropDown.Items = {};
+            app.TYPEDropDown.ValueChangedFcn = createCallbackFcn(app, @TYPEDropDownValueChanged, true);
+            app.TYPEDropDown.Layout.Row = 1;
+            app.TYPEDropDown.Layout.Column = 2;
+            app.TYPEDropDown.Value = {};
+
             % Show the figure after all components are created
             app.UIFigure.Visible = 'on';
         end
diff --git a/ui/selectchannels.m b/ui/selectchannels.m
new file mode 100644
index 0000000..cadcb8d
--- /dev/null
+++ b/ui/selectchannels.m
@@ -0,0 +1,309 @@
+classdef selectchannels < handle
+    %LSL CHANNEL SELECTION  
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    properties(Constant)
+        figwidth  = 512;
+        figheight = 512;
+        padding = 8;    
+        buttonheight = 24;
+        panelwidth = selectchannels.figwidth-2*selectchannels.padding;
+        tablewidth = selectchannels.panelwidth-2*selectchannels.padding;
+        panelheightrequired = 128;
+        panelheightchannels = selectchannels.figheight - ...
+            4*selectchannels.padding - ...
+            selectchannels.panelheightrequired - ...
+            selectchannels.buttonheight;
+        tableheightrequired = selectchannels.panelheightrequired - ...
+            2*selectchannels.padding - 16;
+        tableheightchannels = selectchannels.panelheightchannels - ...
+            2*selectchannels.padding - 16;
+    end
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    properties
+        hFig           matlab.ui.Figure;
+        hRequiredPanel matlab.ui.container.Panel;
+        hChannelsPanel matlab.ui.container.Panel;
+        hRequired      matlab.ui.control.Table;
+        hChannels      matlab.ui.control.Table;
+        hButton        matlab.ui.control.Button;
+        hStyleOk       matlab.ui.style.Style;
+        hStyleNotOk    matlab.ui.style.Style; 
+        selected       uint32  = [];
+        isok           logical = false;
+    end
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    events
+        Done
+    end
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    methods (Access = private)
+        
+        % returns true if channel matches a requirement or no requirements
+        function r = isChannelVisible(self, channel)
+            lenreqs = size(self.hRequired.Data, 1);
+            if lenreqs == 0
+                r = true;
+                return
+            end
+            for idx = 1:lenreqs
+                if self.hRequired.Data(idx, 4) == channel.type && ...
+                   self.hRequired.Data(idx, 5) == channel.unit
+                    r = true;
+                    return;
+                end
+            end
+            r = false;
+        end
+        
+        % updates ok status
+        function updateOK(self)
+            global myprotocols;
+            global mydevices;
+            chreq = myprotocols.selected.fh.requires().channels;
+            chlsl = mydevices.selected.lsl.channels;
+            self.isok = ~isempty(self.selected);
+            for idxreq = 1:length(chreq)
+                found = 0;
+                for idxlsl = [self.selected]
+                    if chreq(idxreq).type == chlsl(idxlsl).type && ...
+                       chreq(idxreq).unit == chlsl(idxlsl).unit
+                        found = found + 1;
+                    end
+                end
+                min = chreq(idxreq).min;
+                max = chreq(idxreq).max;
+                if found < min || found > max
+                    self.isok = false;
+                    if isvalid(self.hRequired)
+                        self.hRequired.Data(idxreq, 3) = found;
+                        addStyle(self.hRequired, ...
+                            self.hStyleNotOk, 'cell', [idxreq 3]);
+                    end
+                else
+                    if isvalid(self.hRequired)
+                        self.hRequired.Data(idxreq, 3) = found;
+                        addStyle(self.hRequired, ...
+                            self.hStyleOk, 'cell', [idxreq 3]);
+                    end
+                end
+            end
+            if isvalid(self.hChannelsPanel)
+                self.hChannelsPanel.Title = "SELECTED: " + ...
+                    length(self.selected);
+            end
+            if isvalid(self.hButton)
+                self.hButton.Enable = self.isok;
+            end
+        end
+        
+        % executed when checkbox is changed
+        function onSelectedChanged(self, ~, ~)
+            newselected = [];
+            for idx = 1:size(self.hChannels.Data, 1)
+                row = self.hChannels.Data(idx,:);
+                if row(1) == "1"
+                    lslidx = str2double(row(2));
+                    newselected(end+1) = lslidx;
+                end
+            end
+            self.selected = newselected;
+        end
+
+        % executed on OK button
+        function onButtonClicked(self, ~, ~)
+            notify(self, 'Done');
+            self.close();
+        end
+    end
+    
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    
+    methods
+        function r = get.selected(self)
+            r = self.selected;
+        end
+        
+        function set.selected(self,val)
+            self.selected = val;
+            self.updateOK();
+        end
+        
+        function show(self)
+            % window already open
+            if isvalid(self.hFig)
+                self.initRequired();
+                self.initSelected();
+                figure(self.hFig);
+                return;
+            end
+            
+            % create figure
+            self.hFig             = uifigure();
+            self.hFig.Visible     = 'off';
+            self.hFig.Name        = 'SELECT LSL CHANNELS';
+            %self.hFig.Color       = [0.0 0.0 0.0];
+            self.hFig.MenuBar     = 'none';
+            self.hFig.Units       = 'pixels';
+            self.hFig.NumberTitle = 'off';
+            self.hFig.Position    = [0, 0, ...
+                selectchannels.figwidth, ... 
+                selectchannels.figheight];
+
+            % create required panel
+            self.hRequiredPanel = uipanel(self.hFig);
+            self.hRequiredPanel.AutoResizeChildren = 'on';
+            self.hRequiredPanel.Title = 'REQUIRED';
+            self.hRequiredPanel.Position = [
+                selectchannels.padding, ...
+                selectchannels.figheight - ...
+                  selectchannels.padding - ...
+                  selectchannels.panelheightrequired, ...
+                selectchannels.panelwidth, ...
+                selectchannels.panelheightrequired
+            ];
+            
+            % create channels panel
+            self.hChannelsPanel = uipanel(self.hFig);
+            self.hChannelsPanel.AutoResizeChildren = 'on';
+            self.hChannelsPanel.Title = 'SELECTED: 0';
+            self.hChannelsPanel.Position = [
+                selectchannels.padding, ...
+                selectchannels.buttonheight + 2*selectchannels.padding, ...
+                selectchannels.panelwidth, ...
+                selectchannels.panelheightchannels
+            ];
+
+            % create required table
+            self.hRequired = uitable(self.hRequiredPanel);
+            self.hRequired.ColumnName = {'MIN'; 'MAX'; 'SEL'; 'TYPE'; 'UNIT'};
+            self.hRequired.ColumnWidth = {50, 50, 45, 'auto', 100};
+            self.hRequired.ColumnFormat = { 
+                'short', 'short', 'short', 'char', 'char' };
+            self.hRequired.RowName = {};
+            self.hRequired.ColumnEditable = [false false false false false];
+            self.hRequired.Position = [...
+                selectchannels.padding, ...
+                selectchannels.padding, ...
+                selectchannels.tablewidth, ...
+                selectchannels.tableheightrequired];
+            self.hRequired.SelectionType = 'cell';
+
+            % create channels table
+            self.hChannels = uitable(self.hChannelsPanel);
+            self.hChannels.ColumnName = {''; 'LSL CH'; 'DEV CH'; 'TYPE'; 'UNIT'};
+            self.hChannels.ColumnWidth = {25, 60, 60, 'auto', 100};
+            self.hChannels.ColumnFormat = { 
+                'logical', 'short', 'short', 'char', 'char' };
+            self.hChannels.RowName = {};
+            self.hChannels.ColumnEditable = [true false false false false];
+            self.hChannels.Position = [...
+                selectchannels.padding, ...
+                selectchannels.padding, ...
+                selectchannels.tablewidth, ...
+                selectchannels.tableheightchannels];
+            self.hChannels.CellEditCallback = @self.onSelectedChanged;
+            self.hChannels.SelectionType = 'cell';
+
+            % create center style
+            s = uistyle();
+            s.HorizontalAlignment = 'center';
+            addStyle(self.hChannels, s, 'column', [2;3]);
+            addStyle(self.hRequired, s, 'column', [1;2;3]);
+            
+            % create ok button
+            self.hButton = uibutton(self.hFig, 'push');
+            self.hButton.ButtonPushedFcn = @self.onButtonClicked;
+            self.hButton.FontWeight = 'bold';
+            self.hButton.Text = 'OK';
+            self.hButton.Position = [
+                selectchannels.padding, ...
+                selectchannels.padding, ...
+                selectchannels.panelwidth, ...
+                selectchannels.buttonheight];
+            
+            % init ok style
+            self.hStyleOk = uistyle();
+            self.hStyleOk.BackgroundColor = 'green';
+            self.hStyleOk.HorizontalAlignment = 'center';
+            
+            % init notok style
+            self.hStyleNotOk = uistyle();
+            self.hStyleNotOk.BackgroundColor = 'red';
+            self.hStyleNotOk.HorizontalAlignment = 'center';
+            
+            % init tables data
+            self.initRequired();
+            self.initSelected();
+            
+            % show
+            self.hFig.Visible = 'on';
+        end
+        
+        function close(self)
+            if isvalid(self.hFig)
+                close(self.hFig);
+            end
+        end
+        
+        function initRequired(self)
+            if isempty(self.hFig) || ~isvalid(self.hFig)
+                return
+            end
+            global myprotocols;
+            req = myprotocols.selected.fh.requires();
+            self.hRequired.Data = strings([0,5]);
+            for idx = 1:length(req.channels)
+                self.hRequired.Data(idx,:) = [
+                    req.channels(idx).min, ...
+                    req.channels(idx).max, ...
+                    0, ...
+                    req.channels(idx).type, ...
+                    req.channels(idx).unit
+                ];
+            end
+        end
+
+        function initSelected(self)
+            if isempty(self.hFig) || ~isvalid(self.hFig)
+                return;
+            end
+            global mylsl;
+            global mydevices;
+            tblidx = 1;
+            lenreqs = size(self.hRequired.Data, 1);
+            self.hChannels.Data = strings([0,5]);
+            for idx = 1:mylsl.lslchannels
+                isselected = ismember(idx, self.selected);
+                isselectedstr = convertCharsToStrings(num2str(isselected));
+                if idx <= size(mydevices.selected.lsl.channels, 1) && ...
+                   self.isChannelVisible(mydevices.selected.lsl.channels(idx))
+                    self.hChannels.Data(tblidx,:) = [
+                        isselectedstr, ...
+                        idx, ...
+                        mydevices.selected.lsl.channels(idx).devch, ...
+                        mydevices.selected.lsl.channels(idx).type, ...
+                        mydevices.selected.lsl.channels(idx).unit
+                    ];
+                    tblidx = tblidx + 1;
+                elseif lenreqs == 0
+                    self.hChannels.Data(tblidx,:) = [
+                        isselectedstr, ...
+                        idx, ...
+                        "", ...
+                        "", ...
+                        ""
+                    ];
+                    tblidx = tblidx + 1;
+                end
+            end
+            self.updateOK();
+        end
+    end
+end