Arduino project · LEDs and lights · Medium
Binary Counter with a Variable
One variable counts from 0 to 15 and four LEDs show it in binary.
What you will learn
- How a counter variable works
- How bit 0, 1, 2 and 3 map to LEDs
- Why 15 is the biggest number with 4 bits
How it works
Every half second "n" goes up by 1 and wraps back to 0 after 15. Each LED shows one bit of n: LED1 is the lowest bit.
Try this next
- Count faster.
- Add a button to freeze the count.
- Show the same number on a digit (0 to 9).
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 binary counter board
Each bulb is one binary digit. Watch the pattern count upward.
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.
- LEDs = the binary digits