Fareed Mohmed← All projects

Arduino project · Buttons and switches · Beginner

Two Lamps, One Slide Switch

The slide switch picks which of two lamps is on: green or red.

What you will learn

  • How a slide switch holds its state
  • How if / else picks one of two outputs
  • How to wire a switch with INPUT_PULLUP

How it works

When the switch is ON the green LED is on and the red is off. When it is OFF the red is on and the green is off. The two LEDs are never on together.

Try this next

  • Add a buzzer for the red state.
  • Add a third position with a second switch.
  • Use relays for a real two-lamp changeover.

The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.

1Choose your Arduino board
2Build the circuit
Parts: sensors and actuators (tap to show or hide)

Try the inputs (virtual sensors)

Pins (you can change them)

PartArduino 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.

#ColourFrom (part and leg)To
3Define the sequence

Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.

4Arduino code





5Parts list and where to buy


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.


#ItemQtySearch termBuy / compare



6Export








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.



7Learn: do’s, don’ts, cautions and tips





In the real world
Two room lamps
Your switch (or a clap) decides which lamp is on in the real room.
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.