The applications that run on Raspberry Pi can’t always identify the serial port that belongs to each Arduino board. If we don’t use an identifier for each board, the serial port may change every time we disconnect or connect the Arduino board to Raspberry Pi.
In this tutorial, I’ll show you how to configure Raspberry Pi to automatically identify two Arduino boards. The procedure can be extended to multiple boards, but in this tutorial, I’ve used two identical Arduino boards.
How To setup Raspberry Pi to identify two Arduino devices
Below are the steps to identify each board separately, regardless of which USB port of the Pi is used.
Step 1: navigate to /etc/udev/rules.d/99-arduino.rules
Step 2: this command returns the two serial ports connected to the Arduino boards
ls /dev/ttyACM*
ls /dev/ttyACM* for two Arduino boards
Step 3: after finding the KERNEL of the two Arduino boards, run for each board the command:
udevadm info -a -n /dev/ttyACM00 | less
Instead of ttyACM00, use the serial port of the Arduino board
Step 4: for each Arduino’s KERNEL, add a line to the file 99-arduino.rules
Step 5: refresh udev
sudo /etc/init.d/udev reload