How to program the PicoCon Motor Controller

By The Pi HutSep 5, 20140 comments

There are two ways to program/use your new PicoCon motor controller:

1. Basic python software

Each motor is directly controlled by two pins, each of which drives one side of the motor
To make the motor go forwards, you make one pin high and the other pin low
To make it reverse, you make the first pin low and the second pin high
For the robot to go forwards both motors should be set to forwards
Similarly to go backwards, both motors should be set to reverse
If you set the left motor to forwards and the right motor to backwards, the robot will spin right
The (physical) pins for the left motor are 19 and 21
The (physical) pins for the right motor are 24 and 26
So to make the left motor go forwards, set pin19 high and pin21 low. You can do this in python with: GPIO.output(19, 1) # pin 19 is left motor A GPIO.output(21, 1) # pin 21 is left motor B

This is covered in a complete python program picoTest01.py covered below.

2. Using the supplied python library

You need to import the library at the start of your python program import picocon
Then you can use the pre-defined functions for moving the motors:

init(). Initialises GPIO pins, switches motors off, etc
cleanup(). Sets all motors off and sets GPIO to standard values
stop(): Stops both motors
forward(speed): Sets both motors to move forward at speed. 0 <= speed <= 100
reverse(speed): Sets both motors to reverse at speed. 0 <= speed <= 100
spinLeft(speed): Sets motors to turn opposite directions at speed. 0 <= speed <= 100
spinRight(speed): Sets motors to turn opposite directions at speed. 0 <= speed <= 100
turnForward(leftSpeed, rightSpeed): Moves forwards in an arc by setting different speeds. 0 <= leftSpeed,rightSpeed <= 100
turnReverse(leftSpeed, rightSpeed): Moves backwards in an arc by setting different speeds. 0 <= leftSpeed,rightSpeed <= 100

To use these functions, you need to preface them with the name of module, picocon.
You need to call the function init() at the start of your program to setup all the input and output pins picocon.init()
You must call the cleanup() function at the end to put all the input and output pins back to where they were picocon.cleanup()
In between you can do whatever you want, so to make the robot go forwards at a medium speed: picocon.forward(50)
to spin left at a fast speed picocon.spinLeft(100)

Downloading the Software Library and Examples

Make sure the Raspberry Pi is connected to the internet
From a terminal window on your Raspberry Pi type the following lines exactly: wget http://4tronix.co.uk/picocon.sh -O picocon.sh bash picocon.sh
This will create a new folder on your Raspberry Pi called picocon
Go into this folder and then you can run the examples like this: sudo python picoTest01.py
picotest01.py simply goes forwards, backwards, spins right and left in a loop. Press Ctrl-C to exit
picotest02.py does the same thing but using the library (see how much simpler the code is)
picotest03.py uses the arrow keys on your keyboard to move the robot. You can also use . or , to speed up and slow down the robot. Also use space to stop.