Lasers! KY-008 laser module for Raspberry Pi & Arduino
You can never go wrong with lasers!
Hall sensor module KY-003 & KY-024 for Raspberry Pi and Arduino
Small magnetic sensor that can be used as a switch or a detector.
Relay Module KY-19 (Songle SRD-05VDC-SL-C)
Switch things on and off! Simple, cheap and functional.
Sensors onboard – DockerPi Sensor Hub
52pi's DockerPi Sensor Hub comes with the most popular sensors packed in a nice I2C-enabled HAT.
Light sensor modules KY-018 and LM393 (3 and 4 pin) for a Raspberry PI...
Read the light values, use it to do things!
Sonar HC-SR04 ultrasonic ranger for a Raspberry PI & Arduino
How to connect HC-SR04 Sonar module to Raspberry Pi
Infrared Sensor HC-SR501 PIR Motion Sensor for a Raspberry PI and Arduino
How to use PIR sensor with your Raspberry PI.
Resistors for beginners
Everything you need to know about the resistors
Beginner’s electronics guide Raspberry Pi, Arduino
Essential electronic knowledge to have to understand circuits better!
Capacitors for beginners
It's almost like going back to the future!