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Photoresistor

Overview

In this lesson, you will learn about Photoresistor. Photoresistor is applied in many electronic goods, such as the camera meter, clock radio, alarm device (as beam detector), small night lights, outdoor clock, solar street lamps and etc. Photoresistor is placed in a street lamp to control when the light is turned on. Ambient light falling on the photoresistor causes street lamps to turn on or off.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name

ITEMS IN THIS KIT

LINK

Elite Explorer Kit

300+

Elite Explorer Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION

PURCHASE LINK

Arduino Uno R4 WiFi

-

Breadboard

BUY

Jumper Wires

BUY

Resistor

BUY

Photoresistor

BUY

Wiring

In this example, we use analog pin ( A0 ) to read the value of photoresistor. One pin of photoresistor is connected to 5V, the other is wired up to A0. Besides, a 10kΩ resistor is needed before the other pin is connected to GND.

../_images/01-photoresistor_bb.png

Schematic Diagram

../_images/01_photoresistor_schematic.png

Code

Note

  • You can open the file 01-photoresistor under the path of elite-explorer-kit-main\basic_project\01-photoresistor directly.

  • Or copy this code into Arduino IDE.

01-photoresistor.ino
 1/*
 2  The code reads the analog value from a photoresistor connected to pin A0 and sends the 
 3  value to the serial monitor. The baud rate for serial communication is set to 9600. 
 4  The code then waits for 10 millisecond before repeating the process.
 5
 6  Board: Arduino Uno R4 
 7  Component: Photoresistor
 8*/
 9
10
11// Define the pin where the photoresistor is connected
12const int photoresistorPin = A0;
13
14// Initialize the serial communication at 9600 baud rate
15void setup() {
16  Serial.begin(9600);
17}
18
19// Main loop where the program runs
20void loop() {
21  // Read the analog value from the photoresistor
22  int sensorValue = analogRead(photoresistorPin);
23  
24  // Send the sensor value to the serial monitor
25  Serial.println(sensorValue);
26  
27  // Wait for 10 millisecond before the next loop iteration
28  delay(10); 
29}

After uploading the codes to the uno board, you can open the serial monitor to see the read value of the pin. When the ambient light becomes stronger, the reading will increase correspondingly, and the pin reading range is 「0」~「1023」. However, according to the environmental conditions and the characteristics of the photoresistor, the actual reading range may be smaller than the theoretical range.