The Arduino community has created a wide variety of modules and shields that can enhance your projects. Here’s the ultimate collection of 21 Arduino Modules that you can get for less than $2 on eBay. Let’s start!
List of the Best 21 Arduino Modules
Sensors are awesome because they allow us to know what’s going on in the outside world. There are sensors for almost anything you can think of. In this guide we’re going to show you a collection of 21 Arduino sensors and modules you can buy for less than $2. We also have instructions on how to use most of them with the Arduino.
1. HC-SR04 Ultrasonic Module
The HC-SR04 ultrasonic sensor uses sonar to determine distance to an object like bats do. It offers excellent non-contact range detection with high accuracy and stable readings in an easy-to-use package. Here’s a complete guide on how to use this module. View this module on eBay ->
2. IR Infrared Obstacle Avoidance Sensor Module
This module is very easy to use and is often used in robots to detect objects near the sensor. These sensors have a digital output pin that outputs a signal when it detects an object. When the module detects an obstacle, the green indicator light on the board lights up. The module detects the distance 2 ~ 30cm, detection angle 35 °. View this module on eBay ->
3. Soil Hygrometer Detection Module Soil Moisture Sensor
This is a simple water sensor that can be used to detect soil moisture. It outputs a high signal when the moisture is above a certain threshold. You can also read an analog signal whose value is proportional to the moisture level. Use this sensor to create an automatic self-watering plant. Here’s the complete guide on how to use the hygrometer module with your Arduino. View this module on eBay ->
4. Microphone Sensor
This sensor is used for sound detection. This module has two outputs: AO (analog output), or DO (digital output). The digital output sends a high signal when the sound the sound intensity reaches a certain threshold. The threshold-sensitivity can be adjusted via potentiometer on the sensor. Learn how to use this sensor with our complete guide. View this module on eBay ->
5. Digital Barometric Pressure Sensor Board
You can use this module to measure the absolute pressure of the environment. By converting the pressure measures into altitude, you have a reliable sensor for determining the height of your robot or projectile, for example. This sensor also measures temperature and humidity. Here’s the complete guide on how to use this sensor. View this module on eBay ->
6. Photoresistor Sensor Module Light Detection Light
You can use this module for light detection with an Arduino. For example, you can build a Night Security Light project. View this module on eBay ->
7. Digital Thermal Sensor Module Temperature Sensor Module
The thermal sensor module is very sensitive to the ambient temperature, generally used to detect the ambient temperature. Through the adjustment of the potentiometer, you can change the temperature detection threshold. View this module on eBay ->
8. Rotary Encoder Module Brick Sensor Development Board
When you rotate the rotary encoder it counts in the positive direction and the reverse direction. Rotation counts are not limited. With the buttons on the rotary encoder, you can reset to its initial state and start counting from 0. View this module on eBay ->
9. MQ-2Gas Sensor Module Smoke Methane Butane Detection
This sensor module utilizes an MQ-2 as the sensitive component and has a protection resistor and an adjustable resistor on board. The MQ-2 gas sensor is sensitive to LPG, i-butane, propane, methane, alcohol, Hydrogen and smoke. It could be used in gas leakage detecting equipments in family and industry. The resistance of the sensitive component changes as the concentration of the target gas changes. Here’s the complete guide on how to use the MQ-2 smoke sensor with the Arduino. View this module on eBay ->
10. SW-420 Motion Sensor Module Vibration Switch Alarm
This module can be used to trigger the effect of various vibration, theft alarm, intelligent car, earthquake alarm, motorcycle alarm, etc. View this module on eBay ->
11. Humidity and Rain Detection Sensor Module
This is a rain sensor. It’s used for all kinds of weather monitoring. Here’s the complete guide on how to use the rain sensor module with the Arduino. View this module on eBay ->
12. Passive Buzzer Module
A simple sound making module. You set high or low to drive this module. By changing the frequency you’ll hear a different sound. View this module on eBay ->
13. Speed Sensor Module
Tachometer is a simple module that allow you to test the speed of the motor. Widely used for motor speed detection, pulse count, position limit, and so on. View this module on eBay ->
14. IR Infrared Flame Detection Sensor Module
Flame detection sensor module is sensitive to the flame, but also can detect ordinary light. This is usually used as a flame alarm. Detects a flame or a light source of a wavelength in the range of 760nm to 1100 nm. Detection point of about 60 degrees, particularly sensitive to the flame spectrum. View this module on eBay ->
15. 5V 2-Channel Relay Module
This is a 2 Channel 5V Relay Module. It allows you to control various appliances that operate at high voltages, with low voltages like 5V. It can be controlled directly by any microcontroller. Here’s the complete guide on how to use the relay module with the Arduino. View this module on eBay ->
16. Breadboard Power Supply Module 3.3V 5V
A simple module to power your breadboard. It supplies both 3.3V and 5V. This is specially useful to power up your breadboard circuits from an external power supply. View this module on eBay ->
17. HC-SR501 Pyroelectric Infrared Sensor Module
A PIR sensor is a little module that allows you to detect movement from humans or pets. It’s easy to integrate with your microcontroller. You can learn here how to use this module with an Arduino. View this module on eBay ->
18. Accelerometer Module
This module measures the acceleration. It’s commonly used in portable devices and video game controllers to detect movement and actions from the player. View this module on eBay ->
19. DHT11 Temperature and Humidity Sensor
It’s a great little sensor to measure temperature and humidity in your room or outside. It integrates seamlessly with the Arduino. You can learn here how to use this module in your project. View this module on eBay ->
20 or 21. RF 433MHz Transmitter/Receiver
If you need data sent from one microcontroller to another, the 433MHz link modules are a cheap way to do that (all data is sent via Radio Frequency). Here’s the complete guide on how to use the 433MHz transmitter and receiver with the Arduino. View this module on eBay ->
[Extra] ESP8266 WiFi Module ($4)
This module costs a little bit more than $2, but it’s totally worth it. You can get one ESP8266 WiFi Module for about $4 on eBay. This module can send emails, host a web server, control LEDs, etc. If you are curious about this module check out my eBook Home Automation Using ESP8266.
Get an Arduino Sensors and Modules Kit
Instead of getting each module separately, there are a wide variety of kits with different Arduino sensors and modules. Getting one of these kits is a great way to get started with your Arduino. Find the best Arduino Sensors and Modules Kits on our blog post.
Need Tutorials to Get Started?
Do you have an Arduino sensor or module and you don’t know how to use it? We have instructions on how to use up to 23 Arduino sensors and modules in our Ultimate Guide For Arduino Sensors/Modules eBook. This guide is completely free and provides schematics, code, and examples on how to use your sensors with the Arduino. Click here to get access to the eBook.
If you are an absolute beginner in the Arduino world, we recommend you following our FREE Arduino Mini Course first, that you can get access here.
Do you have all these modules? Are you thinking about ordering one of theses modules listed above?
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41 thoughts on “21 Arduino Modules You Can Buy For Less Than $2”
Its a good post for those using Arduino, but for other microcontrollers too! Why the restriction? All modules uses common interfaces like i2c and in this way is possible use them with other platforms that are no Arduino. I have some of these and I am using it with PIC Microcontrollers. Despite of it, is a very good post.
A great collection of low cost sensors. As it happens, I already obtained most of them, so as to show them at a local maker meeting, where I ran an ‘ESP workshop’.
For ESP beginners, I think the NodeMCU board is the best choice, doesn’t need a USB to TTL converter or an external power supply. Only a little more expensive than the ESP-01, but well worth the money.
Really like your website, keep up the good work!
Very good collection of sensors useful for a variety of applications.
yes i want these modules
Good day. I are search the guia and the 21 modules
I don’t have only 3 sensors from this list, 2 of them already ordered to test it out 🙂
I have at least 7 of them.
I want to buy these 21 modules. But i dont know how ? Please tell me.
Most electronics stores have them or you can visit the links I mention in the blog post.
What about the nRF24L01 RF transceiver modules? One “receiver” can receive data from up to 6 “transmitters”. A very robust data packet integrity algorithm is built-in.
That’s right. I’ve missed that one Johnny! Thanks
Concerning the use of ‘Arduino’ in the title I think that lets anyone know that these are useful with many devices/microcontrollers. And I have 8 now with a 9th on the way. They are very much fun to play with. I’ve made many motion activated nightlights as gifts. Great work Rui!
Thank you for your feedback David. Yes, I agree with you, I’ll be more careful with naming the post next time. These modules are compatible with any microcontroller.
Have you ever seen a project for a magnetometer using a sensor board? I have seen mechanical solutions using lasers and mirrors and a magnet, and have successfully built one, but I am looking for a simpler solution. Thanks! Great work.
Jim in Sweden
M interested for 21 Arduino Modules to Buy For Less Than $2
Thank you for reading!
I have 5 & they are all very good, just started playing with the $5 (it was when I bought it) AD9850 DDS module, very interesting & quite versatile. Love Arduino stuff have 3 different Arduino I use currently but would like to know more about wifi shields. Rui love your work its great, long may it continue you have helped my coding on more than one occasion for that I thank you.
Itz a great work. I have used 8 sensors in your list.I am gonna order all the remaining 13 sensors…..
Here’s also a great list of sensors and modules: http://ebay.to/1Qt4vh3
Very Nice, Thanks!
It’ a great collection and nice summarized.
I like to read your posts
Thank you Sneppe!
I need a light sensor for arduino for my final year project. Any suggestions..??
Depending on the accuracy of your project, if you search for LDR Arduino you should find what you’re looking for
I need more information
About which sensor?
Sensor vary use full
First time at ur site. Impressed. Got my interest back in arduino. Lost interest couldnt get display to work
Cool! Those modules are what i needed for my planned builds. Thank you.
Thank you for sharing this valuable info
A very nice put together tutorial. All information in one place. Thank you.
hi i’m currently doing my final year project. it is about bus system. i’d like to create my own tpms for measuring the tire pressure and then send the reading to dashboard of the bus and also the data is send to my own server. can you recommend me what type of pressure sensor i should use for bus tires and how the data are send, either using transmitter/receiver or wifi module or another method that easier for me to develop as a beginner in arduino. hopefully you can help me thanks in advanced
Unfortunately, I’m not familiar with that subject.
There are pressure sensors that can easily be integrated with an Arduino or ESP8266/32 like the BME280 or BMP180.
However, I’m not sure whether they are suitable for your project or not.
With what you’ve described, I think that a wi-fi module like the ESP32 would be the best method to create a server and send data.
I hope this helps.
I think Wemos is good module too. It include USB connector and 3.3v regulator. So we can program directly from PC.
Yes, it is.
Thank you for your suggestion. 🙂
Nice post. This post will help the beginners.