irsensor.py

import time
import digitalio
from analogio import AnalogIn

class IRSensors():
    def __init__(self, 
        l_en, l_a, l_b, l_adc,
        c_en, c_a, c_b, c_adc,
        r_en, r_a, r_b, r_adc,
        avg = 5
    ):
        # Setup IR LED enables
        self.l_en = digitalio.DigitalInOut(l_en)
        self.c_en = digitalio.DigitalInOut(c_en)
        self.r_en = digitalio.DigitalInOut(r_en)
        for p in [self.l_en, self.c_en, self.r_en]:
            p.direction = digitalio.Direction.OUTPUT
            p.value = False

        # Setup ADCs
        self.l_adc = AnalogIn(l_adc)
        self.c_adc = AnalogIn(c_adc)
        self.r_adc = AnalogIn(r_adc)

        # Setup differential pair enables
        self.l_a = digitalio.DigitalInOut(l_a)
        self.l_b = digitalio.DigitalInOut(l_b)
        self.c_a = digitalio.DigitalInOut(c_a)
        self.c_b = digitalio.DigitalInOut(c_b)
        self.r_a = digitalio.DigitalInOut(r_a)
        self.r_b = digitalio.DigitalInOut(r_b)
        for p in [self.l_a, self.l_b, self.c_a, 
                    self.c_b, self.r_a, self.r_b]:
            p.direction = digitalio.Direction.OUTPUT
            p.drive_mode = digitalio.DriveMode.OPEN_DRAIN
            p.value = True # High Z mode

        # Preallocate memory for storing values
        self.lir_a, self.lir_b = 0, 0
        self.cir_a, self.cir_b = 0, 0
        self.rir_a, self.rir_b = 0, 0

        self.avg = avg

    def scan(self):
        # Enable IR LEDs
        for p in [self.l_en, self.c_en, self.r_en]:
            p.value = True

        # Reset all values to 0
        self.lir_a, self.lir_b = 0, 0
        self.cir_a, self.cir_b = 0, 0
        self.rir_a, self.rir_b = 0, 0

        # Read 'a' channels
        for p in [self.l_a, self.c_a, self.r_a]:
            p.value = False
        time.sleep(0.001)
        for _ in range(self.avg):
            self.lir_a += self.l_adc.value
            self.cir_a += self.c_adc.value
            self.rir_a += self.r_adc.value
        for p in [self.l_a, self.c_a, self.r_a]:
            p.value = True

        # Read 'b' channels
        for p in [self.l_b, self.c_b, self.r_b]:
            p.value = False
        time.sleep(0.001)
        for _ in range(self.avg):
            self.lir_b += self.l_adc.value
            self.cir_b += self.c_adc.value
            self.rir_b += self.r_adc.value
        for p in [self.l_b, self.c_b, self.r_b]:
            p.value = True

        # Compute averages
        self.lir_a, self.lir_b = self.lir_a / self.avg, self.lir_b / self.avg
        self.cir_a, self.cir_b = self.cir_a / self.avg, self.cir_b / self.avg
        self.rir_a, self.rir_b = self.rir_a / self.avg, self.rir_b / self.avg
        
        # Disable IR LEDs (save power)
        for p in [self.l_en, self.c_en, self.r_en]:
            p.value = False