5.Potentiometer and RGB LED

Objective

You are going to create a potentiometer-based circuit. The goal is to turn on a specific color of the RGB (red, green, blue) LED based on the position of the potentiometer.

Components

1 Metro M0 Express
1 breadboard
4 Legged RGB LED
Potentiometer(use the ones in your kit, it may look different)
3 Resistors (330 Ohms)
Wires

Concepts

Wiring

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

Note:

For common anode RGB LED, connect the longest leg to 3.3V (instead of ground).
For common cathode RGB LED, connect the longest leg to ground.

Potentiometer

Coding/Programming

Note: For common anode RGB LED, True turns the LED off and False turns the LED on.

import board

import digitalio

import time

from analogio import AnalogIn

L1 = digitalio.DigitalInOut(__________)

L1.direction = digitalio.Direction.__________

L2 = digitalio.DigitalInOut(__________)

L2.direction = digitalio.Direction.__________

L3 = digitalio.DigitalInOut(__________)

L3.direction = digitalio.Direction.__________

analog_in = AnalogIn(__________)

while True:

pot = analog_in.value

print((analog_in.value, ))

# Observe the changes of potentiometer values (pot) on the Serial

if (pot >= __________) and (pot < __________):

L1.value = __________

time.sleep(2)

L1.value = __________

time.sleep(1)

elif (pot >= __________) and (pot < __________):

L2.value = __________

time.sleep(2)

L2.value = __________

time.sleep(1)

else:

L3.value = __________

time.sleep(2)

L3.value = __________

time.sleep(1)

Solution (common anode RGB LED)

import board

import digitalio

import time

from analogio import AnalogIn

L1 = digitalio.DigitalInOut(board.D11)

L1.direction = digitalio.Direction.OUTPUT

L2 = digitalio.DigitalInOut(board.D10)

L2.direction = digitalio.Direction.OUTPUT

L3 = digitalio.DigitalInOut(board.D9)

L3.direction = digitalio.Direction.OUTPUT

analog_in = AnalogIn(board.A2)

while True:

pot = analog_in.value

print((analog_in.value, ))

# observe the changes of soft potentiometer values (pot) on the Serial

L1.value = True #off

L2.value = True #off

L3.value = True #off

if (pot >= 400) and (pot < 700):

L1.value = False #on

time.sleep(2)

L1.value = True #off

time.sleep(1)

elif (pot >= 200) and (pot < 400):

L2.value = False #on

time.sleep(2)

L2.value = True #off

time.sleep(1)

else:

L3.value = False #on

time.sleep(2)

L3.value = True #off

time.sleep(1)

Solution (common cathode RGB LED)

import board

import digitalio

import time

from analogio import AnalogIn

L1 = digitalio.DigitalInOut(board.D11)

L1.direction = digitalio.Direction.OUTPUT

L2 = digitalio.DigitalInOut(board.D10)

L2.direction = digitalio.Direction.OUTPUT

L3 = digitalio.DigitalInOut(board.D9)

L3.direction = digitalio.Direction.OUTPUT

analog_in = AnalogIn(board.A2)

while True:

pot = analog_in.value

print((analog_in.value, ))

# observe the changes of soft potentiometer values (pot) on the Serial

if (pot >= 400) and (pot < 700):

L1.value = True

time.sleep(2)

L1.value = False

time.sleep(1)

elif (pot >= 200) and (pot < 400):

L2.value = True

time.sleep(2)

L2.value = False

time.sleep(1)

else:

L3.value = True

time.sleep(2)

L3.value = False

time.sleep(1)

Back