I have a Raspberry Pi with this FTDI cable and a Roomba 560. The Roomba has an SCI port to allow for control of the roomba via serial. I installed the PySerial library on the pi and send valid commands to Roomba, but the roomba doesn't respond. I have the TXD of the cable attached to the TXD of the roomba, the RXD on the cable wired to the RXD on the roomba, and a ground on the cable wired to the ground on the roomba (everything in it's respective port). I do not have power going from the cable to the roomba or vice-versa.
What I can't figure out is why the commands aren't working. There's no error message upon running the python code. This is the information sheet for the Roomba's SCI port.
import serial ser = serial.Serial('/dev/ttyUSB0') # this is the defualt Roomba baud rate ser.baudrate = 57600 # Start SCI - puts into safe mode ser.write(chr(128)) # Enable full mode ser.write(chr(131)) # Spot clean ser.write(chr(134)) print 'Done'