Arduino project · Distance and parking · Medium
Distance Digit with Close Alarm
The digit shows distance in tens of centimetres and the buzzer sounds under 15 cm.
What you will learn
- How to show a value on a digit and sound an alarm
- How to use the same reading twice
- How to choose limits
How it works
One reading is used by two steps: one maps it to a digit from 0 to 9, the other turns the buzzer on when the object is closer than 15 cm.
Try this next
- Make the alarm beep faster as you get closer.
- Show the number on an LCD.
- Add a red LED.
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 car backing towards a wall
Move the distance slider. The car in the real scene drives closer to the wall as the distance falls, with sound waves from its sensor, exactly like a parking sensor.
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.
- Distance sensor = the sensor on the car bumper
- LEDs, buzzer, display = the warnings you see and hear in the car