Build on your Level 1 circuit by adding an input sensor. It’s up to you what kind of sensor to use: a potentiometer (rotary or linear), light sensor, or ultrasonic sensor. Either way, your approach will be pretty similar when building the circuit and writing the code.
At this level you can get started with one of the tutorials below. Plan on doing more research to complement the materials you find here, and always plan on tweaking the project to make it your own once you have completed a tutorial.
- Follow this SparkFun tutorial if you are using a potentiometer
- Follow this SparkFun tutorial if you are using a light sensor
- Follow this Instructable if you are using an ultrasonic sensor