Introduction to Programming and Physical Computing Seminar
Leonard A. Rieck
CONTEXT
Ultrasonic Counter System – Explanation
This system uses an ultrasonic sensor to detect when an object passes in front of it.
Every time something comes closer than x cm, the Arduino counts one pass and lights up fewer red LEDs, showing how many passes remain.
A green LED stays ON while there are still passes left.
When all 10 red LEDs turn OFF, the system activates an alert — the buzzer beeps repeatedly, and all red LEDs blink to show that the limit is reached.
The OLED display shows:
- the number of passes remaining,
- the current distance,
- and whether the path is “CLEAR” or “BLOCKED.”
You can press the reset button to set the counter back to zero, which also makes a short double beep.
Future Improvements
In the future, the system can be upgraded by adding a second ultrasonic sensor.
With two sensors placed side by side, the Arduino could detect the direction of movement — knowing whether an object is going in or out.
This would turn the project into a bidirectional counter, allowing it to track both entries and exits accurately.
Other possible improvements include saving the count to memory, adding wireless communication to send data to a phone or PC, and using a larger display for clearer information.
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