3.0 KiB
Introduction
The 640 board is used to drive up to 6 DC motors and 2 Servo motors.
Getting started
Board layout
Setup
Attaching the power
Attaching a Servo
Attaching a motor
Attaching an RC receiver
Programming the 640
Python
Introduction
The Python libraries for the 640 board and some example scripts are available via our GitHub repository. To install them open a terminal window on your Raspberry Pi (unless you are running with only the command line) and enter the following:
$ git clone https://github.com/darkwaterfoundation/darkwater_python_640.git
Example scripts
Now that you have downloaded the 640 libraries you should have a new directory called *darkwater_python_640, so let's move into that directory
$ cd ./darkwater_python_640
If you list the files in this directory, you should see a few test scripts
$ ls -al
640motortest.py
This script will start each motor port, in the forwards direction, in turn from left to right and then do the same backwards. To run the script enter the following:
$ python 640motortest.py
640servotest.py
This script will move any servos connected to the servo headers left, then center, then right. To run the script enter the following:
$ python 640servotest.py
640steppertest.py
This script divides the 6 motor ports into 3 stepper motor ports. Motor 1 and 2 will be stepper 1, motor 3 and 4 will be stepper 2 and motor 5 and 6 will be stepper 3.
Each stepper will be moved forwards and backwards through 200 steps when the test script is run:
$ python 640steppertest.py
The 640 board API
Now you know everything works, it's time to write your own scripts. So create a new python script in your editor, within the darkwater_python_640 directory with a memorable name and add the following lines to import our libraries:
import time
from darkwater_640.darkwater_640 import dw_Controller, dw_Motor, dw_Servo
Create a controller
The dw_controller object controls access to all the elements on the 640 board, so the first thing we need to do is create a controller - we pass in the address of the 640 board as a parameter - the default address is 0x60
dw = dw_Controller( addr=0x60 )
Now that we have the controller created, we can access all the connectors on the board.
Select a Motor
There are 6 motor ports on the 640 board numbered 1 to 6 from left to right (with the ports facing you ).
If we want to control a motor on port number 1 then we need to request the motor object for that port from our controller - this is very easily done with a single line
m1 = dw.getMotor(1)