Volta Sensor Decoding [TOP]

Let’s walk through a real-world decoding scenario: Decoding a Carbon Monoxide (CO) sensor.

This is where the continuous voltage becomes discrete numbers. Volta Sensor Decoding

def decode_volta_pwm(pin, min_ppm, max_ppm):
    t_high = measure_high_time(pin)
    period = measure_period(pin)
    duty = t_high / period
    if duty < 0.1 or duty > 0.9:
        raise ValueError("Out of valid duty range")
    ppm = min_ppm + (duty - 0.1) / 0.8 * (max_ppm - min_ppm)
    return ppm
def read_volta_i2c(bus, addr=0x68):
calib = bus.read_i2c_block_data(addr, 0x0A, 6)
# Interpret as 3 float32 values
c0, c1, c2 = struct.unpack('<fff', calib)
temp_raw = bus.read_i2c_block_data(addr, 0x20, 2)
temp = temp_raw[0] + temp_raw[1] / 256.0
return c0, c1, c2, temp
 Output:  The user sees "400 ppm CO" instead of raw voltage