7. Personal Nightlight

Objective

You are going to create a photoresistor and LED light-based circuit. This circuit is a voltage-divider! The photoresistor changes its resistance based on how much light it detects from the environment. The resistance normally decreases with more light intensity. The main goal is to use the photo-resistor to turn on the LED; by covering the photoresistor, the LED should turn brighter. It’s a nightlight!!

Wiring

Follow the circuit diagram provided to wire the Metro M0 Express.

Coding/Programming

import board

import pulseio

import time

from analogio import AnalogIn

led = pulseio.PWMOut(__________)

lightLevel = AnalogIn(__________)

while True:

print((lightLevel.value, ))

time.sleep(0.1)

led.duty_cycle = 40535 - lightLevel.value

#theoretically should be 65535 - lightLevel.value

time.sleep(0.1)