Programming the USB 16 SSC in Python under Linux (or Windows

For anyone who’s interested I’ve put together a simple test program for anyone using Python as it seems to be an excellent and quick way to get projects done. I find I write a lot of short programs for general purpose (fun) projects that get recycled after a week, so it is great for that.

It wouldn’t take much to get this running under Windows, if you must. :wink:

Here it is. Feel free to post questions if you have issues on it:

# Python serial servo tester for Pololu USB 16 servo controller
# Author: Jim Munro <jimmn_1999<at>yahoo<dot>com>
# Simple test program to test your controller works under linux
# tested and worked under Ubuntu Linux 'Feisty'
# Note: this is testing the controller under the SSC mode and not
# the special Pololu mode.  The benefit, is that it's much easier to
# when getting started, the down side is that you lose some of the
# advanced functionality provided.  It should be trivial to modify
# this to handle the appropriate strings once you get this working.

# Prerequisites:
#    Python installed (tested with 2.5)
#     PySerial installed (ver 2.2) ''
#    Your serial controller is plugged in to your USB port
#       should be autodetected and device created under /dev/ttyUSB#
#      where # is the device #.  Likely will be ttyUSB0
#      will need to change below if a number other than 0 is created.

import serial  # import PySerial libraries

START_BYTE = '\xff'

#general purpose test function to write out the serial string
#on the serial port.
def ss(servo, pos):
         servo_num = servo + 16  # note that the port is always n+16
         s = '%c%c%c' % (START_BYTE, chr(servo_num), chr(pos))
         print 'Moved Servo: %s to pos:%d' % (servo, pos)

ser = serial.Serial('/dev/ttyUSB0')  # set up the serial port using the default device (see note above)

#a little servo exercise
for i in range(0,255):
     ss(0,i)  # only testing a single servo


Hey Jimmn,
I too am a Python fan and found your code very useful in getting my servo controller going.
I’ve posted a little bit of code on another thread:
It uses the pololu comms mode and has uses classes if anyone is interested.