Arduinos are great microcontroller boards with plenty of interesting features, but they can't do much without additional components. There are loads of unique sensors available on the market for Arduino boards. This gives you plenty of choices, but what Arduino sensors are out there, and how do you use them?
1. Water Level Sensor for Leak Detection
Electronics and water are famous for their destructive relationship, but this first sensor puts this common conception to the test. Water level sensors, or leak detection sensors, measure the water level in a container. The sensor has to be submerged in the water for this to work properly.
Arduino leak sensors only have three pins to connect, making them easy to wire up with your Arduino board and pair with other components. The Geek Pub guide provides everything you need to get started with your water level sensor.
2. Thermal Camera Sensor
Most people would agree that thermal cameras are cool. Giving you the ability to see temperatures, cameras like this have loads of useful applications, but they can also provide a lot of entertainment. Arduino thermal camera sensors are typically low-resolution thanks to the low processing power of these boards.
This Arduino Project Hub guide shows you how to set up an AMG8833 thermal camera with an OLED display for an Arduino. This sensor is relatively complex to set up, but it works with older Arduino boards like the first-gen Uno.
3. Water pH Level Meter
Measuring the pH level of a water source can give you a range of information about the liquid. Its oxygen content, hardness, and a range of other factors impact the pH of water, and the math to convert the digital data into something you can read is easy so long as you know the water temperature.
This How to Electronics guide shows you how to set up your pH sensor with an Arduino board. You will need to do some research to figure out how to find the data you want, but setting up the hardware couldn't be easier.
4. PIR Motion Sensor
Motion sensing is useful for a range of applications, from intruder detection to home automation. PIR motion sensors use infrared light to detect movement. Light is emitted and the sensor will trigger if it can't detect its reflection, enabling a basic form of motion detection based on the appearance of shadows.
These sensors only have three pins, making them easy to wire up and code. You can follow this Random Nerd Tutorials guide to get started with your Arduino motion sensors, but there are plenty of other guides available to get you started.
5. Flame Sensor
Smoke detectors are great for use in the home, providing protection against fires that produce smoke. Some fires don't produce very much smoke, though, and this is where a flame sensor comes in. Capable of detecting flames from about 3 ft away, these small sensors are great for those with 3D printers or other fire hazards at work or home.
This Arduino Project Hub guide shows you how to set up an analog flame sensor with an Arduino board. It's worth keeping in mind that nothing will beat a proper professionally built fire detector, but this sort of tool is still useful to protect your workspace from fires.
6. Capacitive Soil Moisture Sensor
Potted plants benefit greatly from regular watering, but this is a chore that many people end up neglecting thanks to their busy schedules. Building a soil moister detector is a great way to solve this problem. Arduino soil moisture sensors are easy to use, with both capacitive and resistive options available.
This Arduino Get Started guide shows you how to set up a capacitive soil moisture sensor with an Arduino. Like many Arduino sensors, soil moisture detectors only have three pins: GND, VIN, and data. This means that they only take up a single data pin on your Arduino board.
7. Heart Rate/Pulse Sensor
Counting your own pulse is a thing of the past with components like a pulse sensor. Arduino pulse sensors have a small infrared LED that is placed on a finger to reliably read the pulse of a human, providing an analog output that is easy to work with and read. This is great for anyone who wants to work on their own fitness or health tools, similar to the heart rate sensor found on Apple Watches.
The Geek Pub guide will help get you started with an Arduino pulse sensor. While sensors like this are reliable, it's worth keeping in mind that your heart rate can tell you a lot of different things. Do plenty of research before reading your own pulse and consult a doctor if you have concerns about your heart rate.
8. Ultrasonic Distance Sensor
Similar to the movement sensor we've already covered, distance sensors measure distance using a variety of methods. In this case, Arduino distance sensors use sound to work out how distant objects are. Ultrasonic waves that humans can't hear are emitted by the sensor, and the time the sound takes to bounce back from an object is used to figure out its distance.
Sensors like this are useful for an array of projects, from DIY remote control cars to digital measuring tools. This handy The Geek Pub guide shows you how to set up your own Arduino distance sensor.
Give Your Arduino Senses With Sensors
This article only scratches the surface of the sensors available for Arduinos online. It's worth exploring the sensors you can find to see if you can draw inspiration for your next big project. You can usually find a guide to help you to use your sensor, but you may have to be creative to make the code work for you.
You can get your hands on large sensor kits for Arduinos, including all the most popular sensors for these boards (including some on this list). This is a great place to start because you always know that the sensors will work properly with your Arduino board.