!/usr/bin/env pybricks-micropython

from pybricks.ev3devices import (Motor, TouchSensor, ColorSensor, InfraredSensor, UltrasonicSensor, GyroSensor) from pybricks.parameters import (Port, Stop, Direction, Button, Color, SoundFile, ImageFile, Align) from pybricks.tools import print, wait, StopWatch

import struct

Declare motors

left_motor = Motor(Port.B) right_motor = Motor(Port.C) steer_motor = Motor(Port.A) forward = 0 left = 0

Auto center steering wheels.

steer_motor.run_until_stalled(250) steer_motor.reset_angle(80) steer_motor.run_target(300,0)

A helper function for converting stick values (0 - 255)

to more usable numbers (-100 - 100)

def scale(val, src, dst): """ Scale the given value from the scale of src to the scale of dst.

val: float or int
src: tuple
dst: tuple

example: print(scale(99, (0.0, 99.0), (-1.0, +1.0)))
"""
return (float(val-src[0]) / (src[1]-src[0])) * (dst[1]-dst[0])+dst[0]

Open the Gamepad event file:

/dev/input/event3 is for PS3 gamepad

/dev/input/event4 is for PS4 gamepad

look at contents of /proc/bus/input/devices if either one of them doesn't work.

use 'cat /proc/bus/input/devices' and look for the event file.

infile_path = "/dev/input/event4"

open file in binary mode

in_file = open(infile_path, "rb")

Read from the file

long int, long int, unsigned short, unsigned short, unsigned int

FORMAT = 'llHHI'
EVENT_SIZE = struct.calcsize(FORMAT) event = in_file.read(EVENT_SIZE)

while event: (tv_sec, tv_usec, ev_type, code, value) = struct.unpack(FORMAT, event)

if ev_type == 1: # A button was pressed or released.
    if code == 310 and value == 0:
        steer_motor.reset_angle(steer_motor.angle()-5)
    if code == 311 and value == 0:
        steer_motor.reset_angle(steer_motor.angle()+5)

elif ev_type == 3: # Stick was moved
    if code == 0: 
        left = scale(value, (0,255), (40, -40))
    if code == 4: # Righ stick vertical
        forward = scale(value, (0,255), (100,-100))

# Set motor voltages. 
left_motor.dc(forward)
right_motor.dc(forward)

# Track the steering angle
steer_motor.track_target(left)

# Finally, read another event
event = in_file.read(EVENT_SIZE)

in_file.close()

mindboards / ev3sources

control the robot using a ps4 gamepad: cod ; 😃 #45