Automatically find Arduino tty from /dev/serial/

[elcojacobs]

The Arduino serial port can be found as a symlink in
/dev/serial/by-id/

We could look for a symlink with arduino in the name in that dir intead of just trying ttyACM0 and ttyACM1

[elcojacobs]

A possible easy way to do this in python is to use serial.tools.list_ports:
It can be invoked from command line:

python -m serial.tools.list_ports -v

Giving for the Arduino Leo:

pi@brewpi ~ $ python -m serial.tools.list_ports -v

/dev/ttyACM0
desc: ttyACM0
hwid: USB VID:PID=2341:8036
1 ports found

And for the Spark Core:

pi@raspberrypi ~ $ python -m serial.tools.list_ports -v
/dev/ttyACM0
    desc: ttyACM0
    hwid: USB VID:PID=1d50:607d SNR=6D7517794852
1 ports found

We can distinguish between devices from their VID:PID

The list_ports module is intended to be used from the command line, but can be used from a python script by including the platform specific version:

https://github.com/elcojacobs/brewpi-script/blob/feature/dfu-flash-tool/utils/flash-dfu.py#L30

[m-mcgowan]

I have added automatic detection to the brewpi connector, it has all the various IDs registered - tried and tested code so that would be a good start.