Arduino project · Displays and counters · Medium
Sprint Timer (Start and Finish Gates)
Cross the start gate and the timer starts. Cross the finish gate and your time shows on the LCD in milliseconds.
What you will learn
- How a stopwatch works in code
- How start and finish gates time a race
- How electronic timing is more fair than a hand stopwatch
How it works
The first gate starts the stopwatch and the second reads how many milliseconds have passed. The result stays on the LCD for 4 seconds.
Try this next
- Show seconds with one decimal place.
- Keep the best time in a variable.
- Add a buzzer at the finish.
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 sprint timer
The runner breaks the start beam, then the finish beam. The clock times the sprint.
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.
- Two IR sensors = start and finish gates