There are many types of sensors available that enable you to interact with electronics, and so it can be difficult to decide which one is best to use for a project. Furthermore, many tutorials show how to use a single sensor with an Arduino, but it can be unclear how to use lots of them in a project that requires lots of detectors (e.g. laser harps, interactive LED tables, etc.). In this instructable, I will review some sensors (listed below) and focus on how to use them with an Arduino. In addition to the review, I will provide some pros and cons for using each one of these sensor types in Arduino projects that require lots of sensors and explain what to do when there are more sensors than there are pins on the Arduino. Hopefully, this instructable will help you pick the best sensor for your project and understand how to wire many of them up so that they can be used with an Arduino.
List of detectors in this review:

- Push buttons
- IR sensors (Active and passive)
- Photodetectors (Photoresistors and phototransistors and photodiodes)
- Ultrasonic sensors
- Capacitive touch sensing”