Arduino motion sensor light At the end of this article you can: Explain PIR sensor applications and how it works Run an 8-Pixel PIR sensor named TPA81 Use the PIR sensor to detect motion and gesture by Arduino Make a cool detector to increase or decrease your speaker volume. Get started quickly with your Arduino Nano 33 IoT by checking out this guide and more tutorials at Newbiely. The LED should turn on either when the lights are off or when there is motion. You could hook up the arduino to the outlet and have it do things once the outlet is switched on. Throughout this tutorial, I'll take you through how to assemble the circuit, sensor calibration, code, and test your prototyp… Jan 10, 2016 · I am hoping there might be a way to reduce range/sensitivity to a very small field. Sensors are devices used to detect and measure physical phenomena such as temperature, light, motion, and pressure. g. So, it can detect motion based on changes in infrared light in the environment. Elevate your Arduino projects with comprehensive sensor kits. Does anyone know of a way to reduce the field as low as maybe a 1 foot radius? I am using them with an Arduino Mega 2560 or an Arduino Uno. By Daniel Kralev (Founder Of Compute Services Technology). Explore comprehensive documentation for the Arduino UNO Motion-Activated Servo and LED Control System project, including components, wiring, and code. When motion is detected, the red LED lights up, the relay is activated, and the servo motor Jul 29, 2021 · Hey guys! I have tried and tested the code that ill write below, this code is for switching On the lights when motion is detected. Learn how to use motion sensor to control MP3 player. It starts working when someone comes in range of PIR motion sensor, it gets activated and passes signal to programmed Arduino which turns-on the light. This clever little project uses motion detection to automate lighting, making life more convenient, energy-efficient, and Such that if there human motion is present then light goes to on state and if there are no human motion light goes to of state. But I can't figure it out. By monitoring light in the infrared spectrum, PIR sensors can sense subtle changes in temperature across the area they're viewing. Explore this and more Arduino UNO Dec 17, 2015 · PIR Motion Sensor with Arduino: how you can auto turn on the room Light when some come inside the room. Apr 14, 2025 · 🔍 Description: This project creates a smart lighting system that automatically turns lights on when someone enters a room and adjusts brightness based on ambient light. This tutorial includes working, Pinout, Wiring/Schematic, Arduino Code & standalone use. Once motion is detected, a servo motor rotates the camera base to point in that direction. Motion sensors For detecting movement, we’ll incorporate motion sensors into our project. In this post, we are going to share how to connect PIR sensor arduino. Jan 21, 2019 · Introducing the PIR Motion Sensor The PIR motion sensor is ideal to detect movement. For that reason they are commonly found in appliances and gadgets used in homes or businesses. So let's start !!! Aug 9, 2024 · This project explains how to create a motion sensor light circuit using an Arduino and a PIR motion sensor. Arduino-based motion-activated LED using a distance sensor and an LED. DIY Arduino PIR Motion Sensor Lighting & Security: From the minds at http://arduinotronics. Dec 20, 2023 · In this tutorial, we will be building a simple Arduino motion sensor that makes use of a PIR sensor to be able to detect motion. blogspot. the sensor is used in many applications like automatic light on and off. Below is a categorized list of widely used Arduino sensors, with detailed explanations and popular examples. Includes wiring diagrams and Arduino code examples. I also added the pins I would like to use for the second sensor and led at the top. Jun 22, 2021 · In this basic tutorial we are going to see how to interface Arduino uno with PIR motion sensor ( HC-SR501 ). Below is a sample of one of the codes my students came up with. Here we will give you an overview of all the different sensors you can use with an Arduino and similar microcontrollers (MCUs). Feb 4, 2023 · A PIR motion sensor-controlled LED with an Arduino UNO microcontroller is a system that uses a PIR motion sensor to detect motion and an Arduino UNO microcontroller to control an LED based on the presence or absence of motion. This simple circuit can be extended to do some pretty cool stuff, for example, activate lights, a speaker and much more. Arduino Motion Sensor Control Led Light: In need of a little helpful tutorial on how to wire and program your new motion sensor with your arduino? Well look no further. Feb 2, 2025 · Overview This guide focuses on interfacing of the HC-SR501 PIR (Passive Infrared) Motion Sensor with an Arduino UNO Board. The detail instruction, code, wiring diagram, video tutorial, line-by-line code explanation are provided to help you quickly get started with Arduino. Ingredients: Motion sensor ($24 U. The LED should be off when there is light and where there isn’t any motion. An embedded system project built to control an LED strip based on motion detection and ambient light using PIR and LDR sensors. In this project, we will show how to build a motion sensor light circuit with an arduino. Arduino Motion & Proximity Alarm Systems: A beginner-friendly Arduino project featuring two types of alarm systems — one using a PIR motion sensor and one using an ultrasonic distance sensor — to detect movement or nearby objects and trigger light and sound alerts. Can you guys help me with the code? like, edit the code that I've written below specifically? int sensor_pin = 8; // Initialized the pin for Jul 4, 2024 · Learn how to integrate a PIR sensor with a piezo buzzer, LCD, and Arduino in this step-by-step guide. Find this and other Arduino tutorials on ArduinoGetStarted. We combined LED lights with a motion sensor to make a cool distance detector. Below, you'll find a comparison of the different versions available in this repository. S. com supplies varieties of motion sensors, such as arduino motion sensor, Tilt Sensor, led motion sensor light, outdoor motion sensor light, motion sensor alarm, shop now! Learn to build a smart traffic light system with Arduino, featuring LED sequencing, sensor integration, and adaptive control for optimized urban mobility. May 27, 2020 · I use Arduino for time setting and bd139 transistor and relay for switching. They play a critical role in applications like automation, robotics, IoT, and environmental monitoring. I have found projects such as this online, however we are trying to code it modeled off of the projects in the Arduino Project book. With a PIR motion sensor integrated with an arduino, we can detect movement and program the arduino to do something once motion is detected. Now I want to add a Fade effect to my lights so that it gradually lights up and also does the same when the lights go out. Learn how to use motion sensor to control LED. Dec 1, 2024 · Automating household or office systems can be achieved using an Arduino Nano, a passive infrared (PIR) motion sensor, and a relay. They are often referred to as PIR, "Passive Infrared", "Pyroelectric", or "IR motion" sensors. Currently they are detecting motion about 15-20 feet away. Mar 23, 2018 · Use this Arduino motion sensor to build burglar alarm systems, home automation systems, or any simple gadget that prevents people from getting into your space! Watch the sensor in action in the video below. Makerguides is a participant in affiliate advertising programs designed to provide a means for sites to earn Jul 29, 2021 · Hey guys! I have tried and tested the code that ill write below, this code is for switching On the lights when motion is detected. PIR sensors are mostly used to detect motion. Arduino Sensors & Actuators guide seriesDetect motion with the PIR sensorPassive infrared (PIR) sensors are very common and typically found in home electronics. This is the working code for 1 sensor and 1 led. Green led turns on only when movement is detected, and the yellow led starts blinking when the time is near to end. Introduction In this project, we’ll build a motion-activated light system using an Arduino and a PIR (Passive Infrared) sensor. So far we have yet to make it work, and I'm not sure what we are doing wrong. These sensors detect movement and trigger specific actions, making them useful for various applications. Find motion, light, and sound modules, as well as specialty sensors like flame and gas detectors. when someone moving in room & light will turn off automatically In this video we are going to learn how to use PIR motion Sensor (HC-SR501) with Arduino so that we can detect if there is any human movement and take some a Mar 10, 2025 · Motion sensors are essential in modern automation projects, playing a key role in security systems, smart lighting, and interactive devices. I want to use a motion sensor to sense me when I come home at night so that a 3W Led will light up so I can see to unlock the house door. Knowing if something is moving is useful in many […] Motion Detector Using PIR Sensor Working and Arduino Interface With Code and Connection: Hey! If you're attempting to make a basic motion sensor project with an Arduino and a PIR sensor, you're on the right site. This concept is commonly applied in security lighting, automatic hallway lights, and energy-saving Once you have uploaded your sketch, try turning the light on and off and moving in front of your arduino. Jun 24, 2025 · Ever wished your lights could read your mind and switch on when you enter a room—no switches, no hassle? With a PIR (Passive Infrared) sensor and the power of an Arduino Uno EK R4 Wi-Fi, that's exactly what you get. In this video, I will show you how to build a simple Arduino motion sensor using a PIR sensor, an LED, and a piezo buzzer. Motion Activated Light With Arduino and HC-SR04 Sensor: I did this project long time ago to light up the kitchen when I open the back door. This could also be used to make a pretty good scarecrow for a garden. The detail instruction, code, wiring diagram, video tutorial, line-by-line code explanation are provided to help you quickly get started with Arduino Nano. Aug 20, 2020 · When there is motion the sensor detects it resulting in an LED light flashing and a buzzer making noise Jun 8, 2017 · Wrapping up In this project you’ve built a night security light with a photoresistor and a PIR motion sensor. With Arduino, you can control your lights using a variety of sensors and inputs, such as motion sensors, light sensors, and even your smartphone. They are small, inexpensive, low-power, easy to use and don't wear out. May 11, 2023 · Hi there, my class is trying to create motion sensor-controlled lights using an Arduino Uno and a PIR sensor. 81K subscribers Subscribe May 27, 2020 · I use Arduino for time setting and bd139 transistor and relay for switching. Time Stamps The PIR sensor arduino allows sensing the movement. There are also 5 LED "status" lights positioned inside the base that will light up anytime one of the PIR sensors detects motion. Arduino Projects: Ultrasonic Distance Sensor Arduino Projects: LED – 4X4X4 LED Cube Arduino Car Projects: Build an Obstacle Avoiding Robot With Less Than $30 Arduino Projects: Servo Potentiometer Control Arduino LED Project: Knight Rider Arduino Projects: PIR Motion Sensor The Difference between Arduino and Raspberry Pi Aug 18, 2024 · how to control a 110 or 220vac Disco Light using only PIR Motion Sensor. May 13, 2016 · This project will show you how to connect an ultrasonic sensor and an Arduino to turn on a light when motion is sensed. Jul 4, 2021 · currently trying to make a motion sensor light that i can turn on and off with sensor detection but also have auto turn off after lets say 15 minutes if left on. When motion is detected, the sensor sends a signal to the Arduino, which then turns on the LED. Sep 18, 2024 · Lighten your workload (and electricity bill)! Build automatic room lights with Arduino & a PIR sensor. This is a great project to practice with relays and with the PIR motion sensor. My Arduino tutorial will show you how to create spooky sound effects triggered by motion using a PIR sensor, MP3 player, and Arduino Uno! Learn how to wire a May 8, 2016 · Hello, I have a code that will turn an led on and off based on the output of a motion sensor. Apr 6, 2024 · How to build an Arduino PIR Sensor circuit: Includes a simple schematic, component list, and an easy-to-build connection diagram. It’s energy-efficient, cost-effective, and perfect for rooms, corridors, or outdoor lighting. May 15, 2018 · Arduino with PIR Motion Sensor | Random Nerd Tutorials In this project we're going to create a simple circuit with an Arduino and PIR motion sensor that can detect movement. It is ideal to detect if a human has moved in or out of the sensor range. A PIR motion sensor, also known as a Pyroelectric Infrared sensor, is a device that detects motion by sensing changes in infrared radiation levels. Learn: how HC-SR501 motion sensor works, how to connect motion sensor to Arduino, how to code for motion sensor, how to program Arduino step by step. In this video, we will discuss how the PIR Sensor works and how to use the PIR motion sensor with Arduino with a simple motion detection circuit. I have tried placing various objects / films in front of the Welcome to the Arduino Motion Detection with PIR Sensor project repository! This repository contains multiple branches, each representing a different version of the Arduino code for motion detection using a Passive Infrared (PIR) sensor. int sensor1 = 4; // Pin of PIR Motion sensor+LDR+Relay, Without Arduino UNO When dark and movement in room: light ON. The idea was when I open the back door, this light turns on for 15 seconds, which will give me enough time to reach the light switch on the opposite wall. When the sensor detects movement, it triggers an LED to turn on for a set duration (e. com. Learn how HC-SR501 motion sensor works, how to connect motion sensor to Arduino Nano, how to code for motion sensor, how to program Arduino Nano step by step. com/RobotsDinosaurs/Arduino/blob/main/ The sensor (PIR) detects the motion and this signal is read by your Arduino board, then light an LED to indicate motion detection, this information is printed in your Serial monitor, do you know what it is ? Parts Needed for Motion Sensor Light Circuit PIR motion sensor Arduino LED The PIR motion sensor is, again, a sensor which can detect movement through picking up infrared radiation. You get complete instructions, codes, wiring schematics, video guides, and detailed explanations of each code line to assist beginners. This project is a motion-activated LED circuit designed to automatically detect movement using a PIR (Passive Infrared) motion sensor. These sensors are great for home security systems and motion-a PIR Motion Sensor Overview At their most fundamental level, PIR sensor's are infrared-sensitive light detectors. In this article, we'll show you how to make a gesture detector by simple components like the PIR sensor and Arduino Nano. , 1 minute), mimicking commercial motion sensor lights that stay illuminated for a short period after detecting motion. We’ll use Passive Infrared (PIR) sensors, which are excellent for detecting heat signatures from pedestrians and vehicles. The idea is that the light dependent resistor should activate the LED if it is dark or the PIR sensor will activate the LED if Arduino Motion Detector Circuit In this project, we will go over how to build a motion detector circuit with an arduino. Discover how the HC-SR501 motion sensor works, how to hook it up to your Arduino Nano 33 IoT, and how to write the code for it—all explained step by step. Control Light Room With Arduino and PIR Motion Sensor: Today, we will see together how you can create an Arduino PIR motion sensor for your room in order to turn ON/OFF the light by detecting human movements. You’ll find simple instructions, sample code, a wiring diagram, a video tutorial, and an easy-to-follow explanation of the code. By this process you can make or connect outdoor light. Jul 1, 2021 · Light tracking made easy with Arduino Jul 2, 2021 • 1311 views • 0 respects environmental sensing lights tracking Components and supplies 1 Arduino Nano R3 4 Resistor 10k ohm 2 SG90 Micro-servo motor 4 Photo resistor 8 Jumper wires (generic) Tools and machines 1 3D Printer (generic) 1 Soldering iron (generic) Project description Code arduino This is the source code for this tutorial Jul 11, 2017 · The idea is simple, pir senses motion, a timer starts decreasing, each time motion is detected the timer resets, when the time ends the relay acts as switch and the lights are turned off. Easy-to-follow guide with circuit diagram, code, and explanations. The primary aim is to create a control system that activates or deactivates electrical devices in response to human movement, enhancing convenience and energy efficiency How to Use a PIR Motion Sensor With Arduino : I ordered a PIR motion sensor recently and thought it would be easy to set up. Arduino Motion Detection Light: PLEASE VOTE! ME IF YOU LIKE IT Hi, this is my new Arduino motion detection light. In this tutorial you will learn how to make motion sensor light control system Jun 12, 2022 · In this project, we are going to learn how to make Arduino circuit that automatically controls a lamp using motion sensor. 💡 Improvements Over Basic Motion Detectors: Dual control using both motion and light detection. We provide code and schematics. Aug 8, 2023 · Hello, I've recently been to an Arduino Level 1 Workshop and after purchasing a starter kit, I came up with my first project. I want to test my ability to code a motion sens… Learn how to use motion sensor to control servo motor. This system intelligently adjusts its behavior based on the environment, ensuring efficient light control and minimal false triggers. What I am trying to accomplish, is to add another sensor and another LED to the system. When no motion is detected, the light remains off, helping to conserve energy. A PIR works by detecting the heat energy in the surrounding environment. Learn to interface RCWL-0516 Microwave Radar Motion sensor with Arduino along with Working, Pinout, Wiring, Jumper Settings, Arduino Code for reading output Sep 1, 2010 · This tutorial will show you how to hack a common security motion sensor to turn an outlet on and off. It is powered by a 9v supply for the Arduino and 5v for the light. Welcome to the Arduino Motion Detection with PIR Sensor project repository! This repository contains multiple branches, each representing a different version of the Arduino code for motion detection using a Passive Infrared (PIR) sensor. In this particular tutorial, we will be making use of both a LED and piezo buzzer to alert us when motion has been detected through the PIR motion Dec 1, 2024 · Automating household or office systems can be achieved using an Arduino Nano, a passive infrared (PIR) motion sensor, and a relay. Aug 3, 2019 · PIR Sensor is short for passive infrared sensor, which applies for projects that need to detect human or particle movement in a certain range, and it can also be referred to as PIR(motion) sensor, or IR sensor. Code:https://github. This guide Jun 7, 2025 · In this tutorial, we will explore how a PIR sensor like HC-SR501 works and how to interface it with an Arduino by making a motion-activated In this project we are going to make a circuit for Motion Sensor Activated Light With Automatic Brightness Adjustment using Arduino, PIR & LDR sensors. Oct 26, 2024 · The Arduino Uno is user-friendly and ideal for beginners and experienced makers alike. Perfect for beginners! Dec 26, 2022 · In this tutorial, we have learned how to detect light using an Arduino and explored various applications of light sensors in maker projects. Testing out different configurations as well. This step-by-step tutorial covers programming, wiring, and setup for smart lighting projects like stair lights, under-bed lighting, and Christmas tree lights. (So basically double it). com/ We wanted to save energy, and create convenience, by adding motion sensors to our lighting circuits. Because it (PIR motion sensor) can detect the motion that’s why it works till someone moving in the room and after few seconds light will get turn off automatically. Learn how to create a lighting automation system using Arduino, HC-SR501 motion sensor, and LED strip. Being that people naturally give off radiation, because of our generated body heat, the motion can easily detect people walking and moving through a vicinity within the sensor's range. Can you guys help me with the code? like, edit the code that I've written below specifically? int sensor_pin = 8; // Initialized the pin for PIR Motion Detector With Arduino: Operated at Lowest Power Consumption Mode: This video demonstrates quick and easy approach of reducing power consumption of ATMEGA 328P based Arduino boards by around 70-75% using PIR or PID sensors for motion detection. . This project uses an Arduino UNO to create a motion-activated control system featuring a PIR motion sensor, a red LED, a relay, and a servo motor. Learn how to use light sensor to control LED. Want to buy motion sensor? DFRobot. Prevents unnecessary lighting . read the article carefully to learn about the project we shared all the detail step by step and if you have any queries you can ask us in the comment Learn about HC-SR501 Passive Infrared PIR Motion Detector module. This is a great Arduino project for beginners to learn how to use the PIR motion sensor. Learn to interface RCWL-0516 Microwave Radar Motion sensor with Arduino along with Working, Pinout, Wiring, Jumper Settings, Arduino Code for reading output Aug 28, 2023 · This Arduino Light sensor circuit is a simple example that shows you how to connect light sensors such as photoresistors, photodiodes, and phototransistors, to an Arduino. Components Required Arduino board PIR sensor module Light Bulb 2 Channel relay module Jumper wires Breadboard Circuit Jul 12, 2019 · In this tutorial you will learn how the HC-SR501 sensor works and how you can use it with Arduino. Search "motion detector" @skynet-robotics Subscribe how to make Motion detection light on off PIR sensor project #howto 9. With this video, you will learn how to connect PIR sensor with Arduino and program the Arduino to detect any moment in the room or around the motion sensor. Learn how to use motion sensor to control piezo buzzer. 5K Dislike 86 Discover how the HC-SR501 motion sensor works, how to hook it up to your Arduino Nano 33 IoT, and how to write the code for it—all explained step by step. In this article, Arduino smart light control project ideas, Mar 21, 2021 · PIR Motion Sensor LED Ceiling Light – Arduino Compatible This motion sensor LED ceiling light board has been designed using 4 white LEDs each of 1-3W, PIR sensor module, Atmega328 microcontroller, low ohm IRLR7843 MOSFET, and few other components. Build DIY motion sensor lights using Arduino/Raspberry Pi! Step-by-step with PIR sensors, LED strips & automation for security & energy saving Jul 8, 2025 · In this article, we will dive into the concept of Arduino-based smart lighting systems, explore how motion sensors enhance the functionality, and provide step-by-step guidance on creating your own smart lighting setup. In this tutorial we are using PIR motion detection sensor to detect motion and turn ON LED bulb and it will remain ON for 2 minutes if no motion detected. Jul 4, 2024 · Learn how to integrate a PIR sensor with a piezo buzzer, LCD, and Arduino in this step-by-step guide. The HC-SR501 sensor is designed to detect motion through infrared signals emitted by living beings, making it ideal for applications like security systems, automated lighting, and motion-activated devices. I wanted to make a continuation to the first video, implementing the addition of a motion sensor. Mar 20, 2025 · 1. Aug 8, 2024 · A passive infrared motion sensor (PIR sensor) is an electronic sensor that measures infrared light emitted by objects in its field of view. Aug 13, 2023 · Sensors are the eyes and ears of an Arduino system, transforming the analog and digital world around us into a language that microcontrollers can understand. The HC-SR501 IR Pyroelectric Infrared PIR Module is a popular and widely used motion sensor that can be easily interfaced with an Arduino microcontroller. Unlock the power of motion detection with Arduino! In this video, we’ll show you how to use a Passive Infrared (PIR) sensor with Arduino to detect motion and light up an LED. This video about PIR Motion Sensor and Arduino for making automatic light. Learn how to create a motion sensor controlled LED light using Arduino. The LED is Motion Detector With LED for Beginners: This is a simple project I made to test some motion sensors I bought. This project deals with 120 volts which can be deadly, so be careful. In this quickstart guide, you’ll learn how to connect a photoresistor to an Arduino board and read out the voltage. If a man or an animal passe… Automating home stuff is fun. By Ahmed Ebeed. Oct 29, 2021 · This project is developed to learn how to use LEDs on arduino with a motion detector. The motion sensor has a Jan 22, 2025 · Overview PIR sensors allow you to sense motion, almost always used to detect whether a human has moved in or out of the sensors range. Find this and other Arduino Nano tutorials on Newbiely. ) Outlet and outlet A beginners Arduino light sensor tutorial showing you how to use an LDR (Light Dependent Resitor) for live light sensing on the serial monitor The PIR sensor arduino allows sensing the movement. When motion is detected in the sensor’s range, an LED light (or relay-controlled bulb) will turn on automatically and stay on for a set time before turning off. When a human or some other object comes into the PIR's field-of-view, the radiation pattern changes, and the PIR interprets that change as movement Jun 26, 2021 · Taking a closer look at the Passive Infrared Sensor. It will detect motion and light an LED when it does. Arduino Motion Sensor: I will be teaching you how to make a motion/ distance sensor with and arduino. When paired with a 5V SPDT relay module, this combination can be used to control various Feb 12, 2025 · Project 1: Motion Activated Light In this project, you’ll use a PIR sensor to detect movement and turn on an LED (or any other light source). Apr 19, 2025 · A motion-activated LED strip system that turns on lights in the dark using input from both a PIR motion sensor and an LDR. Basically, the PIR motion sensor measures infrared light from objects in its field of view. Wiring diagram and example codes included! Learn: how light sensor works, how to connect light sensor to Arduino, how to code for light sensor, how to program Arduino step by step. When paired with an Arduino, a motion sensor can be programmed to respond intelligently, creating an efficient and responsive system. PIR sensor: The PIR sensor stands for Passive Infrared sensor. Full Tutorial: https://pimylifeup. 5K Dislike 86 Mar 21, 2018 · This Arduino Security Camera uses 5 PIR motion sensors to detect any movement within a 180º radius. They detect the heat that is emitted by the body of a person in a room as it contrasts against the background heat. However, I found that I only became more confused looking up many online tutorials that suggested different things to try. It is a low cost sensor whic… Discover: how to use the HC-SR501 motion sensor and Arduino UNO R4 to detect the human, how to to connect the motion sensor to Arduino UNO R4, coding for the motion sensor, and detailed programming guidance for Arduino UNO R4. and so simply put,The main idea of this project is to light… Learn how to build an automated light control system with Arduino UNO R4, HC-SR501 motion sensor, and LED strip. Mar 3, 2025 · Interactive props with sound! Learn how to use Arduino, PIR motion sensor & MP3 player to trigger custom sound effects including wiring & Arduino code examples. Step-by-step instructions and circuit diagram included. If you like Arduino projects, make sure you check our latest Arduino course: Arduino Step-by-step Projects – Build 25 Projects Thanks for reading, Sara Nov 7, 2023 · Learn to use a passive infrared (PIR) sensor to add motion detection to your Arduino projects. PIR stand for “Passive Infrared”. Arduino Motion Detection Simple Project: This is a very basic tutorial for Arduino beginners , we tried to keep it simple and to the point, how to use PIR motion detection sensors and how to control LED based on the sensor outpu. Arduino distance sensor project HC-SR04 Ultrasonic Distance sensor in Arduino projects for beginners Russel Electronics 2. We are going to make a circuit for Motion Sensor Activated Light With Automatic Brightness Adjustment using Arduino, PIR & LDR By Najad. By using a photoresistor, we can easily measure the intensity of light in our surroundings.