I posted a similar question before as I was just getting started with the project but I wasn't specific enough so got a weak response from the SE community. But now I am at a point where I have Python code which is supposed to rotate a servo through Pololu's Maestro Serial servo controller (https://www.pololu.com/product/207). Based on the "Serial Interface" section of the user's guide (https://www.pololu.com/product/207/resources), I sent a sequence of numbers starting with decimal 170 and 12, which are the "first command byte" and the "device number data byte", respectively. The user guide says that 12 is the default device number, so I tried changing it to 18 because that's how many servos my servo controller can drive. But that doesn't make much difference because the servo doesn't rotate at all. The numbers after that are the same as the example from the user's guide. I am not sure what the 4, 112 and 46 are doing, but the 0 targets the servo port "0" on the servo controller (the port to which my servo is connected). The servo doesn't move, regardless of what sequence of numbers I put in. I have very little experience, so if you guys could point me in the right direction or at least point to some useful resources on the web, I'd be very grateful.
import serial import struct import time import Adafruit_BBIO.UART as UART drive_Motor_Port = serial.Serial(port = "/dev/ttyO1", baudrate=9600) drive_Motor_Port.close() drive_Motor_Port.open() drive_Motor_Port.write(chr(170)); # User guide says we must start with OxAA = 170 drive_Motor_Port.write(chr(18)); # Device number drive_Motor_Port.write(chr(04)); drive_Motor_Port.write(chr(00)); drive_Motor_Port.write(chr(112)); drive_Motor_Port.write(chr(46)); time.sleep(5);