When you’re stuck for ideas for your next Arduino project, and easy place to start is by looking for a sensor to learn to use. Once you’ve got the sensor up and running, you’ll be able to find an application for it and turn it into a project. Here are 10 different modules which are available on Amazon and eBay for under $5, in fact most of them are under $2.

HC-SR04 Ultrasonic Distance Measuring Sensor

HC-SR04-Ultrasonic-Sensor

The ultrasonic distance measurement module uses ultrasonic sound waves to measure the distance between itself and an object. It is a really easy module to use and an entire Arduino library exists to assist you with programming your Arduino to operate with it. Here’s the purchase link for the HC-SR04 Ultrasonic Distance Measuring. Here’s our guide on using the ultrasonic module with your Arduino.

Speed Sensor Module

Speed Sensor Module

This tachometer allows you to measure the speed of a motor. It can be used to measure both the speed and position of a motor. Here’s the purchase link for the Speed Module.

Photoresistor Module

Photoresistor Sensor Module

The photoresistor module allows your Arduino to be triggered through a digital input when a certain level of light is detected. The light level set point can be set through the on board potentiometer. Here’s the purchase link for the Photoresistor Module. You could try build your own lightning camera trigger using this module.

Barometric Pressure Module

BMP280 Pressure Sensor Module

Barometric pressure can be used to determine the height of your robot or projectile or as a sensor on your weather or home automation system. Here’s the purchase link for the BMP280 Pressure Module.

5V Relay Module

5V Relay Module

A relay module allows you to switch and control a wide range of devices which the Arduino is not able to provide enough current to switch itself. Here’s the purchase link for the 5V Relay Module.

Sound Level Microphone Detection Module

Sound Level Microphone Detection Module

This sound level sensor module has two different outputs, one which is a set point set by the on board potentiometer which triggers the output at a certain sound level and the second provides a scaled voltage output for the instantaneous sound level. Here’s the purchase link for the Sound Level Microphone Detection Module.

Infrared Obstacle Avoidance Sensor (Pack of 4)

Infrared IR Obstacle Avoidance Sensor This module can be used to detect objects in front of the sensor between 2cm and 30cm. It is all adjusted on the module and the Arduino simply monitors its single output pin. This is one of the more useful and cheapest modules on this list as you get 4 in a pack for under $3! Here’s the purchase link for the Infrared Obstacle Avoidance.

3 Axis Accelerometer Gyroscope Module

3 Axis Accelerometer Gyroscope ModuleThis module is used to measure the acceleration and inclination of an object. It can be used to build a gesture based controller or is also commonly used for drone applications. Here’s the purchase link for the 3 Axis Accelerometer Gyroscope Module.

Pyroelectric Infrared PIR Motion Detector

Pyroelectric Infrared PIR Motion Detector

This module is a PIR motion detector which uses infrared to detect humans and pets. It can be used to turn lights on and off or create a simple alarm system. Here’s the purchase link for the Pyroelectric Infrared PIR Motion Detector.

Soil Hygrometer Sensor Module For Moisture

Soil Hygrometer Moisture Sensor

In a pack of 5 for under $5, this sensor is also a bargain. These sensors can be used to automate your garden watering process or to water your indoor plants. It’s the beginning of an interesting addition to your home automation system. Here’s the purchase link for the Soil Hygrometer Module For Moisture.

Now that you’ve found a few new sensors to work with, you should have a few ideas for some new projects. If you’re still looking for new ideas, have a look at the projects in this book:

Practical Arduino Projects
Practical Arduino Projects – Available as an eBook or in Print.

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10 Arduino Modules You Can Buy For Less Than $5

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