Sensors, Motors, Actuators 
Programmable Robotics
Building and Programming a Robot
Creating digital measuring devices
FM Radio /Oscilloscope
Traffic Lights setup
Programming Melodies
Electromagnetic Relay
Ultrasonic Ranging Ranging module
Arduino Module 
TV Remote Programming
Anti Theft alarm
Microcontrollers(in Washing  machine/Micro Oven)
Digital Counter/Stop Watch/Clock
Digital Metronome(Musical device checker)
RF ID
Remote Control
Multimeter
Digital Thermometer
Sound level meter
Ultrasonic Ranging Module
Distance Walks
Smart Lights
Musical Robot
Police CAR
Safe trip Robot
and many more…..