Arduino project · LEDs and lights · Easy
Lamp That Remembers On or Off
A push-button toggles a lamp. After a power cut the lamp comes back in the state it had before, like a real smart switch.
What you will learn
- How a toggle works with one variable
- How to restore a state after power-on
- Why smart switches remember their state
How it works
The variable "s" is 0 or 1. Each press adds 1 and wraps back to 0 after 1. The value is saved, so the lamp state survives a reset.
Try this next
- Use a relay with a real lamp.
- Add a second lamp with its own memory.
- Add a status beep when the lamp is switched.
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
A lamp in a room
Your LED is the lamp in this room. When the LED turns on in the simulator, the room lights up.
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.
- LED = the ceiling lamp