Arduino project · Displays and counters · Medium
Visitor Counter That Remembers
An IR sensor at the entrance counts each visitor. The total stays after a power cut and a button clears it for a new day.
What you will learn
- How an IR sensor counts people
- Why shops keep the count through a power cut
- How a clear button works
How it works
Every time the beam is broken the count rises by one and is saved. The button sets the count to 0 and saves that. Real EEPROM survives about 100,000 writes, so a real program should save only when the number changes, as this one does.
Try this next
- Show the total on a 4-digit display.
- Add a light that stays on while someone is near.
- Count in and out with two sensors.
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 room that counts who walks in
Each time the IR sensor is blocked a person passes through the door and the count goes 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.
- IR sensor = a person in the doorway
- Relay = the room light (where used)