The robot code is pretty simple: it continually reads data from the IR receiver and based on what it reads, controls the motor direction and speed.

The robot code is below. Save it to the Circuit Playground Express on the robot as code.py.

import board
import pulseio
import adafruit_irremote
from adafruit_crickit import crickit

# Control debug output: it takes time so don't unless you're debugging
DEBUG_LOG = False

# Control codes
STOP = 0x01
ROTATE_LEFT = 0x02
ROTATE_RIGHT = 0x03
FORWARD = 0x04
FORWARD_LEFT = 0x05
FORWARD_RIGHT = 0x06
REVERSE = 0x07
REVERSE_LEFT = 0x08
REVERSE_RIGHT = 0x09

left_wheel = crickit.dc_motor_1
right_wheel = crickit.dc_motor_2


def log(s):
    """Optionally output some text.
    :param string s: test to output
    """
    if DEBUG_LOG:
        print(s)


# These allow easy correction for motor speed variation.
# Factors are determined by observation and fiddling.
# Start with both having a factor of 1.0 (i.e. none) and
# adjust until the bot goes more or less straight
def set_right(speed):
    right_wheel.throttle = speed * 0.9

def set_left(speed):
    left_wheel.throttle = speed


# Uncomment this to find the above factors
# set_right(1.0)
# set_left(1.0)
# while True:
#     pass


# Create a 'pulseio' input, to listen to infrared signals on the IR receiver
pulsein = pulseio.PulseIn(board.IR_RX, maxlen=120, idle_state=True)

# Create a decoder that will take pulses and turn them into numbers
decoder = adafruit_irremote.GenericDecode()

while True:
    # Listen for incoming IR pulses
    pulses = decoder.read_pulses(pulsein)

    # Try and decode them
    try:
        # Attempt to convert received pulses into numbers
        received_code = decoder.decode_bits(pulses)
    except adafruit_irremote.IRNECRepeatException:
        # We got an unusual short code, probably a 'repeat' signal
        log("NEC repeat!")
        continue
    except adafruit_irremote.IRDecodeException as e:
        # Something got distorted or maybe its not an NEC-type remote?
        log("Failed to decode: {}".format(e.args))
        continue


    if received_code == [STOP] * 4:
        log("STOP")
        set_left(0.0)
        set_right(0.0)
    elif received_code == [ROTATE_LEFT] * 4:
        log("ROTATE_LEFT")
        set_left(-0.25)
        set_right(0.25)
    elif received_code == [ROTATE_RIGHT] * 4:
        log("ROTATE_RIGHT")
        set_left(0.25)
        set_right(-0.25)
    elif received_code == [FORWARD] * 4:
        log("FORWARD")
        set_left(0.5)
        set_right(0.5)
    elif received_code == [FORWARD_LEFT] * 4:
        log("FORWARD_LEFT")
        set_left(0.0)
        set_right(0.5)
    elif received_code == [FORWARD_RIGHT] * 4:
        log("FORWARD_RIGHT")
        set_left(0.5)
        set_right(0.0)
    elif received_code == [REVERSE] * 4:
        log("REVERSE")
        set_left(-0.5)
        set_right(-0.5)
    elif received_code == [REVERSE_LEFT] * 4:
        log("REVERSE_LEFT")
        set_left(-0.25)
        set_right(-0.5)
    elif received_code == [REVERSE_RIGHT] * 4:
        log("REVERSE_RIGHT")
        set_left(-0.5)
        set_right(-0.25)
    else:
        log("UNKNOWN")

This guide was first published on Aug 08, 2018. It was last updated on Aug 08, 2018.

This page (Robot Code) was last updated on Nov 02, 2020.