Robotic Light Sensors

A light sensor has the role to detect the light and the result is translated into output analog value. The sensor output depends by light intensity and has low or high values. The robot can be programmed to react when the light sensor detects a certain amount of light. In some words, a light sensor is a simple robotic part that uses light sensitive materials like Galium to generate signals. When a photon hits the Galium a small signal is generated.

Light sensors come in different shapes and dimensions, they can be rounded, with corners, or even half a sphere. These sensors are simple, cheap, and can be used in a wide range of applications like a wheeled robot that follow a line or change the statements depending on light intensity. Any user can decide how to use the potential of light sensors in new and innovative ways for building wonderful robots, from simple to advanced applications.

How Light Sensor Works

A light sensor is simple and is used for light detection. On the market are many types of sensors with slightly different way of works. At least one thing is common to all light sensors available. All of these use a photocell or photo-resistor to detect the presence of light. When the light is detected by a photocell or photo-resistor the value of the output signal is changed. A converter takes the analog signal and convert into digital output.

Tutorials And Resources

Below are displayed 9 most used light sensors in robotics and up to 16 tutorials that teach you how to programming and interface the light sensors with Arduino board.
Below you’ll find 16 tutorials that teach you how to interface and programming Arduino board to display the values generated by sensors. Each sensor has attached one or more quality tutorials with explanations and programming lines that can be copied into Arduino memory and start building simple applications based on these programs.



Photocells are simple, cheap, small sensors for light detection. All these tutorials teaching you how to interface a photocell sensor, how to test, and how to program an electronics board to detect the light intensity with a Photocell sensor.


  • Arduino Lesson 9. Sensing Light – lesson for learning how to use analog input for measuring the light intensity with the simple photocell sensor. In this project uses a 5mm red LED to generate light, while other components like resistors, shift register, or half-size breadboard are interfaced with the Arduino UNO board;
  • Motion and Light Sensors with Arduino (and Without) – example how a simple light sensor can be used together with a motion sensor and the Arduino board to turn on an LED when is darkness or when motion is detected;
  • Photocells – from basic information to programming lines, Photocells are a comprehensive tutorial from where users can learn how the light is measured, how to test a photocell sensor, connecting and using a photocell to Arduino Diecimila board;



With a 20mm outer diameter, the rounded light sensor from LilyPad has a maximum output of 5V when is exposed to the light and a minim of 0V when is dark.




BH1750 light intensity sensor was designed in the labs of DFRobot and can be appreciated for a higher resolution and the ability to be used in a wide range of applications.


  • Light Sensor – guide how to interface the BH1750 light sensor and display the light detection in Lux measurement units of illumination;



Designed to act like a transistor, the TEMT6000 ambient light sensor has an increased analog voltage on the output pin when the light intensity is high.




A small light sensor designed for applications where is required to detect the differences between different visible colors.

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