28/10/2019
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Introduction 

A photoresistor or photocell is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity. A photoresistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits. It's also called light-dependent resistor (LDR).

In this tutorial you will learn how to use a photoresistor with Raspberry PI.

Let's get started!

What you will need - Hardware

The Circuit

The connections are pretty easy, see the image above with breadboard circuit schematic.

The code

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#Libraries
import RPi.GPIO as GPIO
from time import sleep
#Set warnings off (optional)
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
#Set Button and LED pins
Button = 23
LED = 24
#Setup Button and LED
GPIO.setup(Button,GPIO.IN,pull_up_down=GPIO.PUD_UP)
GPIO.setup(LED,GPIO.OUT)
#flag = 0

while True:
    button_state = GPIO.input(Button)
    print(button_state)
    if button_state == 0:
        GPIO.output(LED,GPIO.HIGH)
    else:
        GPIO.output(LED,GPIO.LOW)
    sleep(1)
    '''
    if button_state==0:
        sleep(0.5)
        if flag==0:
            flag=1
        else:
            flag=0
    if flag==1:
        GPIO.output(LED,GPIO.HIGH)
    else:
        GPIO.output(LED,GPIO.LOW)  
    '''
Download the code from here and open it with Thonny Python IDE or run it from terminal.
raspberrypi_button_led.zip
File Size: 0 kb
File Type: zip
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Well Done!

You have successfully completed our first Raspberry Pi "How to" tutorial and you learned how to use a photoresistor
I hope you liked this, let me know in the comments.

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