making decent headway on the DIY route. i have a few PIDs decoded for G8X m3/m4
50hz RPM
50hz ACCELERATOR PEDAL
50hz BRAKE PRESSURE
25hz GEAR
25hz STEERING ANGLE
RPM and PEDAL come in at 100hz but the Bluetooth LE drivers on all the Arduino devices are terrible. nRF52 or ESP32!
My basic design is an Adafruit Feather ESP32s3 (or Adafruit Huzzah32 ESP32) with Feather Wing CAN bus transceiver (ESP32 has a SJA1000-like CAN controller built into the chip) The ESP32s3 is newer chip with Bluetooth 5.0, but drivers are so terrible, there is not real gains, I just prefer the USB-C vs USB micro B.
I started out with a nRF52 chip, but its performance was maybe 100 frames / second total. The ESP32s3 I can get about 350 frames / second before the Bluetooth stack starts dying.
I have developed my own CAN bus driver, so i can take lots of shortcuts since i only care about reading data. I can get over 2500 frames / second (the max my car broadcasts over the PT-CAN bus) without issue.
The ESP32 is dual-core, so i have CAN bus on one core, Bluetooth on the other, use a FreeRTOS Queue to pass data from the CAN bus interrupt handler to the bluetooth core and send that over Bluetooth LE to racechrono.
RaceChrono screenshot:
https://photos.app.goo.gl/Kbn5eceCnLTmVuXQ9ESP32 build:
https://photos.app.goo.gl/yBsnSb2GYug3SNcv7Next steps are to see if i can write my own BLE slimmed down driver with the ESP32 SDK and get past that 350 frames / second mark.
It would be nice to have a WiFi interface to RaceChrono for DIY devices, as that I feel is much more stable / performance drivers in the arduino world, vs trying to use BLE for performance path. BLE is fine for basic communication, but none of the Arduino drivers are hardened for performance on the BLE side.
Comments
could also just reduce the BLE payload to PID + value, instead of sending all the extra CAN data so each BLE message would be 4 bytes for PID and 1-2 bytes for data. that would reduce the data payload in each BLE from 12 bytes total to 5-6 bytes total
email me at magnust@gmail.com if you are interested in trying out my integrated ESP32-S3 CAN board with built in 12V power support from car/bike
https://github.com/MagnusThome?tab=repositories
🙂👍
A WiFi interface is available, and I have been using it for a year or so -- streaming $RC3 and GPS data via an old ESP8266 serial/WiFi interface at insane speeds. It is definitely faster and more stable than the Bluetooth SPP I used before.
> send_string( "AT+CWSAP_CUR=\"\",\"\",5,3\r\n" );
> delay(1000);
> send_string( "ATE0\r\n" ); // Echo off
> send_string( "AT+UART_CUR=1000000,8,1,0,0\r\n" ); // 1Mbps, 8 bits, 1 stop bit, no parity, flow control
> LL_USART_Disable( RC_dev ); // disable to change baud rate
> LL_USART_SetBaudRate( RC_dev, 96000000U, LL_USART_OVERSAMPLING_16, 1000000 );
> LL_USART_Enable( RC_dev );
> send_string( "AT\r\n");
> send_string( "AT+GMR\r\n");
> send_string( "AT+CWMODE_CUR=2\r\n"); // 2 = softAP mode (allow phone to connect via WiFi)
> send_string( "AT+CIPMODE=0\r\n" ); // Prepare normal mode
> send_string( "AT+CIFSR\r\n" ); // Query IP address
> send_string( "AT+CIPMUX=1\r\n"); // Enable multiple connections.
> send_string( "AT+CIPSERVER=1\r\n"); // Create a TCP server. Default port = 333
> delay(1000); // wait for connection
The serial port "RC_dev" is connected to the ESP8266 . You might need to insert some delays to let the ESP process the AT-commands -- check via a logic probe! This function sends data to RaceChrono:
> void send_AT(char* str) {
> size_t len = strlen(str);
> if ( len > 0 )
> {
> char at_com[]="AT+CIPSEND=0,xxx\r\n";
> sprintf(&at_com[13],"%03u\r\n",len);
> send_string(at_com); // Book the transmission and length
> delay(1); // wait for ">" ToDo: Read and check the response
> send_string(str);
> }
>}
> void send_string(char* str) {
> size_t len = strlen(str);
> for (; len > 0; --len, ++str) {
> LL_USART_TransmitData8( RC_dev, *str );
> while (!LL_USART_IsActiveFlag_TXE(RC_dev)) {} // Blocking mode
> }
> *(str-len)=0; // clear the buffer, strlen=0
>}
since all CAN bus packets would fit in UDP packet, it would be interesting to test WiFi + UDP, and interesting to pack more than 1 CAN bus data frame into a UDP packet as well, but the dual core ESP32 with CAN bus interrupts on one core and networking on another core seem to do well enough.