5. Soft Potentiometer and RGB LED

Objective

You are going to create a soft potentiometer based circuit. The goal is to turn on a specific color of the RGB (red, green, blue) LED based on the position of where you press on the soft potentiometer (or how much pressure you apply on the force sensor).

Components

1 Metro M0 Express
1 breadboard
4 Legged RGB LED
Soft Potentiometer / Force Sensor
3 Resistors (330 Ohms)
1 10kΩ Resistor
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.

Soft Potentiometer

Force Sensor

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 soft 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)

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