3.19 Button Control LED

3.19.1 Overview

In this project, we control the ON/OFF of the LED via an AD button. The LED will light up if we press the button and it goes off when we press the button again.

3.19.2 Test Code

In Files, open 3-19-tableLamp.py and click .

Code:

'''
 * Filename    : 3-19-tableLamp
 * Thonny      : Thonny 4.1.4
 * Auther      : http//www.keyestudio.com
'''
from machine import Pin,ADC
import time

led = Pin(23,Pin.OUT)
key = ADC(Pin(33))			#set ADC input pin to GPIO 33
key.atten(ADC.ATTN_11DB)	#set voltage range to 0-3.3V
key.width(ADC.WIDTH_12BIT)	#set ADC resolution
#define a variable to shift the state of led
ledState = False

while True:
    keyVal = key.read()	#read the analog value of button
    if keyVal > 3500:	#if value > 3500: red button is pressed
        #reverse the value of ledState: if False（1）, it changes to True（0）; True becomes False
        ledState = not ledState
        time.sleep_ms(500)
    #led.value() is different from led.on() / led.off(), in led.value(), 0(led off) or 1(led on) need to be filled in.
    led.value(ledState)

Result:

After uploading the code, press the red button and the red LED lights up; press it again and the LED goes off.