Arduino project · Displays and counters · Medium
Counter That Remembers (EEPROM and LCD)
A counter that does not forget. Button 1 adds one, button 2 sets it to zero, and the number is kept in the Arduino permanent memory (EEPROM) even when the power is off.
What you will learn
- What EEPROM is and why it keeps numbers without power
- How to save and load a variable
- Why you must not save in a very fast loop
How it works
At every turn the program first loads the number from EEPROM and shows it. When a button is pressed it changes the number and saves it again. Press button 1 a few times, then use the Reset control of the simulator: the count comes back. 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
- Count to 9999 on a 4-digit display.
- Keep a second counter for button 2.
- Add a buzzer beep for every 10th count.
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 visitor counter at the door
Press the up and down buttons. The board shows the count and remembers it even after power 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.
- Buttons = people in and out
- LCD = the board