This is an example Arduino Sketch that presents a webserver controlling a CANBUS device.
Specifically:
- a DJI Robomaster GM6020 motor,
- on a Wemos D1 Mini ESP8266,
- via the Seeed Studio CAN-BUS shield v1.2
- Just a demo/exploration. Not active.
- HTTP API
Connect ESP8266 to CAN-BUS shield via SPI.
Important: Edit source to match your CS pin to your configuration. It's typically D8 on this board but I couldn't use that for some reason.
Connect CAN-H/CAN-L to 2pin CAN cable from GM6020.
Important: Edit source's MOTOR_ID to match GM6020 dip switch ID. Don't forget to turn on termination.
Connect power to GM6020.
Connect 2pin CAN cable to GM6020.
Important: Edit this software to reflect your wireless access point settings.
Connect ESP8266 to your computer.
Set serial/COM port appropriately.
Flash this software on your ESP8266.
Start Arduino Serial Monitor. Use 115,200 as the baud rate.
Observe ESP8266 serial output. It should look something like this:
starting wifi..
wifi up: 192.168.1.212
mdns up: canbot0
starting canbus..
Enter setting mode success
set rate success!!
Enter Normal Mode Success!!
canbus up
http up: http://192.168.1.212
Visit this URL in your browser for a fairly uninteresting status display.
Turn the motor and watch the "p" value change appropriately.
To use this as part of a large software assembly, use its API
$ curl http://192.168.1.212/get
{"ga":0,"p":0,"r":0,"a":0,"t":0}
ga - goal angle - range 0..8192
p - current spindle position - range 0..8192
r - current rpms - range 0..360 ?
a - current amps - range 0.. ?
t - current temp - range 0..160
The motor will attempt to match a position given. This presently doesn't work too well - it stops early or overshoots. You could add a PID controller to the loop. I am investigating a reinforcement learning approach.
Here's how you use the goal function:
$ curl http://192.168.1.212/set?angle=8181
{"gp":8181}
This software is basically unsupported, but feel free to open an issue, or hit me up on the Telegram ESP32 channel: