After you have got an LED blinking the most fun you can have with an Arduino or Raspberry Pi is taking in information from the surrounding environment and acting upon it. To help you decide on what sensors might interest you here are my favorite that can be used with both the Arduino and Raspberry Pi. I’v used each sensor in projects ranging from high altitude weather balloons to gloves that translate sign language.
1. Altitude, Pressure, Temperature
The MS5607 Altimeter Module by Parallax is an incredible sensor. It will give extremely accurate, altitude, pressure, and temperature readings. I’v put this sensor on a high altitude weather balloon and sent it to the edge of space (video here). Others have tested this module at 120,000ft!
Anytime you need to detect a flex, or bend, a flex sensor is probably the part for you. As the sensor is flexed, the resistance across the sensor increases. I’v used this flex sensor in my Sign Language Glove. These guys are great for detecting how much fingers are bent or even as “whiskers” on a robot!
3. Knock, Vibration
Piezo elements come in handy when you need to detect vibration or a knock. You can use these for tap or knock sensors pretty easily by reading the voltage on the output. They can also be used for a very small audio transducer such as a buzzer.
This motion sensor is simple to use. Power it up and wait 1-2 seconds for the sensor to get a snapshot of the still room. If anything moves after that period, the ‘alarm’ pin will go low. This is the first sensor I played with when I got my Arduino. Its very easy to use and has many practical applications!
A distance sensor is a must have if you are building an autonomous robot. They are super easy to use with just 3 pins. 5V, GND and Signal. The effective range is from about 1 inch to 10 feet (2 centimeters to 3 meters). I’v used a similar ultrasonic distance sensor in a cane I invented for the visually impaired (project here).