Microcontrollers
Small, self-contained computers on a single chip designed to control hardware. They read inputs (sensors, buttons) and control outputs (LEDs, motors) in embedded systems.
Arduino Uno
One of the most popular Arduino boards, and the type we use in the MakerLabs. 
Website: Arduino UNO
https://docs.arduino.cc/hardware/uno-rev3/
ESP32
A powerful microcontroller with built-in Wi-Fi and Bluetooth. 
(Image: Mouser Electronics)
Website: ESP32
Raspberry Pi
A small, low-cost single-board computer (not just a microcontroller). It can run an operating system like Linux and is used for programming, automation, and multimedia projects. 
Website: Raspberry Pi