Arduino project · Buttons and switches · Beginner
Keypad LED Selector
Press 1, 2 or 3 on the keypad to light the red, yellow or green LED while the key is held.
What you will learn
- How 16 keys are read with 8 wires
- How the Keypad library scans rows and columns
- How to react to a key
How it works
The library switches each row on in turn and checks which column sees it. That tells it which key is down. The program then turns the matching LED on while that key is held and off otherwise.
Try this next
- Make keys 4, 5 and 6 switch the LEDs off.
- Add a buzzer that clicks with each key.
- Make the LED stay on until another key is pressed.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
Remote-controlled lamps
Press a key or a remote button. The matching lamp in the real room switches on or off.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Keypad / IR remote / phone = the controller
- LEDs = the lamps