NightyNight v2 (NightyPyte - The MicroPython Edition)

[TOC]

Introduction

An ESP8266 based, WS2812 night light with wifi based (web) configuration and MQTT control.

Like PixelBall ( Gitlab / Github ) on steroids. Whilst PixelBall is simple and pre-programmed, NightyNight allows for initial setup to be done via a web interface, accessible by connecting to it, whilst it runs as a WiFi access point. Once configured, it connects to an MQTT server and accepts commands.

Designed as a Night Light for my Son.

Background

Initially, NightyNight (v1) was designed around an ESP8266 running nothing but the raw code itself. I liked it because I could write it in C and just have it run on the hardware directly.

Unfortunately the development model for this method is slower - somewhat similar to AVR - where you write some code, flash to test, debug etc. I was also originally working on ESP-01's and therefore didn't have much choice in what the stack was either way due to the constraints it posed.

I eventually found the WEMOS Mini-D1 boards ( and their clones ) and thought they were too good to miss. Whilst costing an extra 50%, it's MORE than worth it considering what you get, not forgetting too that the 50% more is a whole $1.50 (AU).

With the new board specs I could now look at heavier base. Additionally, all the extra pins would allow for greater functionality. I don't recall how now, but I stumbled on MicroPython and thought it would be a good tool for the job, thus NightyPyte began it's life.

Enhancements from v1

Power Supply

In version 1, the ESP-01 expects 3.3v, so a power circuit needed to be used to drop the 5v USB input power down to acceptable limits. With the Mini-D1, this is done for us.

Interface

In version 1, the interface I was designing was based around using a single button for input, and only the coloured LED as output. With the extra pins and an OLED screen I had laying around, I will now have an actual interface on a screen, driven by 1, 2 or even 3 buttons.

Installation

1. Download the latest ESP8266 build of MicroPython image; eg. For v1.18, released 2022-01-17:

wget https://micropython.org/resources/firmware/esp8266-20220117-v1.18.bin

2. Erase the flash:

esptool.py --port /dev/ttyUSB0 erase_flash

esptool.py v1.2
Connecting...
Running Cesanta flasher stub...
Erasing flash (this may take a while)...
Erase took 10.2 seconds

3. Flash the image:

esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash -fm dio --flash_size=detect 0 esp8266-20220117-v1.18.bin

esptool.py v1.2
Connecting...
Auto-detected Flash size: 32m
Running Cesanta flasher stub...
Flash params set to 0x0240
Writing 618496 @ 0x0... 618496 (100 %)
Wrote 618496 bytes at 0x0 in 13.9 seconds (354.8 kbit/s)...
Leaving...

4. At this point you should be able to connect to the device via picocom(8) or screen(1) etc:

baud=115200
stty \
    ispeed ${baud}  \
    ospeed ${baud}  \
    min          1  \
    time        10  \
    -icrnl -onlcr   \
    -opost -isig    \
    -icanon -iexten \
    -echo -echoe    \
    -echok -echoctl \
    -echoke         \
</dev/ttyUSB0 && picocom -i --baud ${baud} --imap lfcrlf /dev/ttyUSB0

5. Once connected, pressing ENTER should show the Python interactive prompt:

>>>

6. Disconnect.

7. If you don't have your own config yet, create one:

cp -ai config.json{.TEMPLATE,}

7. Run the minify.bash script to shrink the HTML/CSS files, eg.

./minify.bash

Minifying files...
          web_nn.SOURCE.css (3944) -->           web_nn.MINIFIED.css (3280): 17% reduced

8. Use something like pyboard.py or uPyLoader or ampy to transfer the NightyNight python files directly to the device. eg.

pyboard.py --device /dev/ttyUSB0 -f cp \
    config.json app.py globs.py ui.py utils.py \
    debug.py config.py main.py boot.py \
    web_server.py web_pyhtml.py web_nn.css \
    index.py index.pyhtml \
    web_reboot.py web_reboot.pyhtml \
    web_config_wifi.py web_config_wifi.pyhtml \
    favicon.ico favicon.16x16.png favicon.32x32.png \
:

• don't forget the : at the end there - it's the destination (the device)

Running

On boot of the ESP8266, Boot (boot.py) script will run.

Boot

boot.py does the following:

• Turns off wifi;
• Turns off blue status LED (connected to Pin 2 (D4);
• Check if the Button (connected to Pin 12 (D6)) is being held down;
• If button is held:
  • Start flashing at increasing speed;
  • If still held after 8 "rounds":
    • Set globs.mode to MODE_DEBUG
    • GOTO Debug Mode;
  • If NOT still held after 8 "rounds":
    • Set globs.mode to MODE_CONFIG
• Load configuration (from config.json);
• If config contains valid wifi settings:
  • Turn on wifi client and try to connect;
• If config does NOT contain valid wifi settings:
  • Set globs.mode to MODE_CONFIG
• If we did not connect successfully:
  • Configure own Access Point (AP);
  • Set globs.mode to MODE_CONFIG
• Run Main (main.py)

Main

main.py does the following:

• Checks the globs.mode variable and routes to either:
  • MODE_CONFIG: Config Mode (config.py:config.launch_app())
  • MODE_APP: App Mode (app.py)

App Mode

app.py does the following:

• Turns the blue status LED on when the button is pressed;
• Turns the blue status LED off when the button is not pressed;

Config Mode

In certain cases, Config Mode (config.launch_app()) can be activated.

Network

Config Mode can be entered when either connected to an existing network, or when running it's own Access Point (AP). The AP will run when either:

1. The connection failed in some way (timed out, password wrong, AP not found etc); or
2. Or, the user selected Config Mode (by holding the button down on boot for less than 8 seconds) and then selected own AP (by pressing the button during the connection (increased pulsing LED) phase).

Own AP

ESSID

When running its own AP, the device sets its SSID to "NightyNight-<hexid>-<ip_address>", where:

• <hexid> - The 8 hexidecimal unique identifier for the device; and
• <ip_address> - The IP address that the device will be listening on, once you connect to it.

Password

The password for this AP will be "configure<hexid>", where:

• <hexid> - The 8 hexidecimal unique identifier for the device.

Configuration

Once in Config Mode, you can connect to the device's AP (if applicable) then direct your browser to http://<ip_address> to configure the device.

Configurable options are:

• Network details
  • SSID
  • Password
• MQTT details
  • MQTT Server
  • MQTT Port
  • MQTT Topic

Once these are saved, a reboot will occur.

Debug Mode

In certain cases, Debug Mode (debug_mode()) can be activated.

Debug Mode does the following:

• Turns on blue status LED
• Launches the REPL interface (on UART 0)

Design Decisions

pyhtml

The reason I seemingly overengineered a html templatey thing is mainly due to the ESP8266's (well, D1 Mini really) memory limitations. With very limited memory, even a basic page couldn't easily be stored as a string in a module and served. Once I knew I had to stream them off "disk", I figured I'd add a way to easily insert variables within the content. Good idea? Dunno yet but it works :)