We controlled our PicoBorg from a remote keyboard control previously using RemoteKeyBorg, but what about using a joystick or gamepad instead?
Well it seems like a good idea to us, so we thought we would make an example to get you going.
This example will work with either a wired or wireless joystick, as long as the Raspberry Pi can see the joystick properly.
Connecting the joystick to the Raspberry Pi
First plug the joystick into Raspberry Pi, this will be into a USB port from either the joysticks cable, or the wireless receiver.
You will now need to run the following to ensure the joystick drivers are installed:
sudo apt-get -y install joystick
Then you will want to run jstest as follows:
If you wiggle one of the analogue sticks up and down you should see output like:
In this case we can see axis 1 is moving, so that is our up/down axis, do the same thing for a left/right movement (they can be the same stick or different, which ever you prefer) and make a note of both numbers.
For those of you trying to get a PS3 controller to work, you will need a bluetooth dongle that the Raspberry Pi is happy with, and the process is a bit more involved.
We followed the guide here to get the PS3 controller to work properly, the axis numbers for the joysticks are:
- Left stick left/right: 0
- Left stick up/down: 1
- Right stick left/right: 2
- Right stick up/down: 3
Get the script running
Now we have a working joystick, we need to download the script code:
cd ~ wget -O JoyBorg.py https://www.piborg.org/downloads/JoyBorg.txt chmod +x JoyBorg.py
However we will also need to change the settings (those numbers you remembered earlier).
Open JoyBorg.py in a text editor, e.g.
On line 33,
axisUpDown should be changed to the first number you noted earlier, e.g.
axisUpDown = 0 if 0 is the axis which changed when moving up and down.
If up / down seems to be swapped, change line 34 to read
axisUpDownInverted = True instead.
On line 35,
axisLeftRight should be changed to the second number you noted earlier, e.g.
axisLeftRight = 1 if 1 is the axis which changed when moving left and right.
If left / right seems to be swapped, change line 36 to read
axisLeftRightInverted = True instead.
Now we are all ready, run the script using:
gksudo is needed to run as sudo (so we can control GPIO pins) and so we can make a window on the screen, which we do for pygame's benefit.
If you get a window popup warning about "Granted permissions without asking for password" it is safe to ignore it, it is just warning you that the window was started with root permissions.
You can download JoyBorg.py as text here.
#!/usr/bin/env python # coding: Latin-1 # Load library functions we want import time import pygame import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setwarnings(False) # Set which GPIO pins the drive outputs are connected to DRIVE_1 = 4 DRIVE_2 = 18 DRIVE_3 = 8 DRIVE_4 = 7 # Set all of the drive pins as output pins GPIO.setup(DRIVE_1, GPIO.OUT) GPIO.setup(DRIVE_2, GPIO.OUT) GPIO.setup(DRIVE_3, GPIO.OUT) GPIO.setup(DRIVE_4, GPIO.OUT) # Function to set all drives off def MotorOff(): GPIO.output(DRIVE_1, GPIO.LOW) GPIO.output(DRIVE_2, GPIO.LOW) GPIO.output(DRIVE_3, GPIO.LOW) GPIO.output(DRIVE_4, GPIO.LOW) # Settings for JoyBorg leftDrive = DRIVE_1 # Drive number for left motor rightDrive = DRIVE_4 # Drive number for right motor axisUpDown = 1 # Joystick axis to read for up / down position axisUpDownInverted = False # Set this to True if up and down appear to be swapped axisLeftRight = 3 # Joystick axis to read for left / right position axisLeftRightInverted = False # Set this to True if left and right appear to be swapped interval = 0.1 # Time between keyboard updates in seconds, smaller responds faster but uses more processor time # Setup pygame and key states global hadEvent global moveUp global moveDown global moveLeft global moveRight global moveQuit hadEvent = True moveUp = False moveDown = False moveLeft = False moveRight = False moveQuit = False pygame.init() pygame.joystick.init() joystick = pygame.joystick.Joystick(0) joystick.init() screen = pygame.display.set_mode([300,300]) pygame.display.set_caption("JoyBorg - Press [ESC] to quit") # Function to handle pygame events def PygameHandler(events): # Variables accessible outside this function global hadEvent global moveUp global moveDown global moveLeft global moveRight global moveQuit # Handle each event individually for event in events: if event.type == pygame.QUIT: # User exit hadEvent = True moveQuit = True elif event.type == pygame.KEYDOWN: # A key has been pressed, see if it is one we want hadEvent = True if event.key == pygame.K_ESCAPE: moveQuit = True elif event.type == pygame.KEYUP: # A key has been released, see if it is one we want hadEvent = True if event.key == pygame.K_ESCAPE: moveQuit = False elif event.type == pygame.JOYAXISMOTION: # A joystick has been moved, read axis positions (-1 to +1) hadEvent = True upDown = joystick.get_axis(axisUpDown) leftRight = joystick.get_axis(axisLeftRight) # Invert any axes which are incorrect if axisUpDownInverted: upDown = -upDown if axisLeftRightInverted: leftRight = -leftRight # Determine Up / Down values if upDown < -0.1: moveUp = True moveDown = False elif upDown > 0.1: moveUp = False moveDown = True else: moveUp = False moveDown = False # Determine Left / Right values if leftRight < -0.1: moveLeft = True moveRight = False elif leftRight > 0.1: moveLeft = False moveRight = True else: moveLeft = False moveRight = False try: print 'Press [ESC] to quit' # Loop indefinitely while True: # Get the currently pressed keys on the keyboard PygameHandler(pygame.event.get()) if hadEvent: # Keys have changed, generate the command list based on keys hadEvent = False if moveQuit: break elif moveLeft: leftState = GPIO.LOW rightState = GPIO.HIGH elif moveRight: leftState = GPIO.HIGH rightState = GPIO.LOW elif moveUp: leftState = GPIO.HIGH rightState = GPIO.HIGH else: leftState = GPIO.LOW rightState = GPIO.LOW GPIO.output(leftDrive, leftState) GPIO.output(rightDrive, rightState) # Wait for the interval period time.sleep(interval) # Disable all drives MotorOff() except KeyboardInterrupt: # CTRL+C exit, disable all drives MotorOff()