Arduino GA1A12S202 Analog Light Sensor example

In this example we will connect a GA1A12S202 Log-Scale Analog Light Sensor to an Arduino.

The features of this sensor are as follows

Output voltage increases with light on the sensor
Logarithmic response not only gives more sensitivity in low light, its also almost impossible to “max-out” the sensor
Dynamic range of 3 to 55,000 Lux
Use indoors and outdoors without needing to recalibrate!

What is Lux though ? Well this helpful table shows some examples

Again these are typically best used in breakout/module form. Here is a picture of the module

Connection and Layout

Vcc – 5v
Gnd – Gnd
Out – A0 (or you can use another analog in pin but you would need to change the code example)

Which you can see in the layout here

Code

This uses a library – https://github.com/arduinolearning/Arduino-Libraries/tree/master/GA1A12S202

[codesyntax lang=”cpp”]

#include "GA1A12S202.h"

GA1A12S202 luxValue(A0);

void setup() 
{
    Serial.begin(9600);
    delay(2000);
}

void loop() 
{
    Serial.print("Raw value = ");
    Serial.print(luxValue.getRaw());
	Serial.println();
    Serial.print("Lux value = ");
    Serial.println(luxValue.getLux());
	Serial.println();
    delay(1000);
}

[/codesyntax]

Testing

Open the Serial monitor and you should something like this, varying the light source will change the value

Raw value = 315
Lux value = 2.42

Raw value = 314
Lux value = 2.42

Raw value = 27
Lux value = 1.09

Raw value = 28
Lux value = 1.08

Links
Adafruit GA1A12S202 Log-scale Analog Light Sensor [ADA1384]