Open speedomenter WIP

OSOM (read as ˈôsəm) is the acronym of Open Speedometer.

Architecture

The new architecture is the following:

Clinet <==BLE==> Master <==2.4GHz==> Slave

where:

• Master: CC2541 <==UART==> PIC <==SPI==> nRF24L01+
• Slave: PIC <==SPI==> nRF24L01+

The client is a device that must be compatible with BLE (Bluetooth 4.x).

The CC2541 (aka NP, aka Network Processor) will run a standard firmware that is in charge of providing a bluetooth connection to the PIC.

Master and Slave will exchange messages over a custom, light-weight, protocol.

Specifications

• Microcontroller: PIC32MX274F256D @72MHz (TODO verify)
• Communication:
  • Bluetooth (master only): HM10 Bluetooth 4.2 Low Energy
  • Wireless: nRF24L01+ @2.4GHz
• Power:
  • LiPo 1s Battery, 1200/2000 mAh (not choosen yet)
  • 5V provided by micro USB, 500 mA MAX
• Sensor: custom made 650nm modulated laser sensor
• Laser source: Red diode laser, 650nm @5mW

PIC PIN assignment

Bluetooth (master only)

PIN	I/O	PPS	Function	Note
6	IN	RPB2	U1RX	PIC <== NP
7	OUT	RPB3	U1TX	PIC ==> NP

nRF24L01+

PIN	I/O	PPS	Function	Note
21	IN	RPB10	INT1	Interrupt generated by nRF24L01+
22	OUT	RPB11	SDO2
23	OUT	-	CS	RB12
24	IN	RPB13	SDI2
25	OUT	-	CE	RB14
26	OUT	RPB15	SCK2

Debug

PIN	I/O	PPS	Function	Note
4	OUT	RPB0	U2TX	PIC ==> PC
5	IN	RPB1	U2RX	PIC <== PC

USB will be available too, with at least a comunication device class (CDC) enumeration.

Sensing

PIN	I/O	PPS	Function	Note
16	IN	-	INT0	Left IN Interrupt
11	IN	RPB4	INT4	Right IN Interrupt

Battery Charger

New PIC analisys required

LEDs

Analisys required.

Note

1. Master only: an extra LED from CC2541 indicates the BT connection status.
2. From the battery charger an extra LED indicates che charging status.