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Project 2.7.5: Manual Trigger Radar

Description This project activates ultrasonic distance measurement only when a push button is held down, conserving power and allowing on-demand readings.
Use case This project can be used in portable measuring devices, battery-powered systems, field inspection tools, and robotics, where distance measurements are taken only when requested to conserve power and reduce unnecessary sensor operation.

Components (Things You will need)

Arduino Uno Arduino USB Cable Breadboard Jumper Wires Push Button Ultrasonic Sensor

Building the circuit

Things Needed:

  • Arduino Uno = 1
  • Arduino USB cable = 1
  • Push button = 1
  • Ultrasonic sensor = 1
  • Breadboard = 1
  • Jumper wires

Mounting the component on the breadboard

Step 1: Place the Ultrasonic sensor and the Push button on the breadboard.

Components on breadboard

NB: Make sure all components are securely placed on the breadboard with correct orientation.

WIRING THE CIRCUIT

Step 2: Connect the VCC pin of the Ultrasonic Sensor to the Arduino 5V pin the Arduino Uno using male-to-male jumper wire.

Wiring diagram

Step 3: Connect the GND pin of the Ultrasonic Sensor to the Arduino GND pin the Arduino Uno using male-to-male jumper wire.

Wiring diagram

Step 4: Connect the TRIG pin of the Ultrasonic Sensor to the Arduino Digital Pin 9 using a male-to-male jumper wire.

Wiring diagram

Step 5: Connect the ECHO pin of the Ultrasonic Sensor to the Arduino Digital Pin 10 using a male-to-male jumper wire.

Wiring diagram

Step 6: Connect one terminal of the push button to Digital Pin 2 on the Arduino using a male-to-male jumper wire.

Wiring diagram

Step 7: Connect the opposite terminal of the push button to GND on the Arduino using a male-to-male jumper wire.

Wiring diagram

Make sure to connect the Arduino USB cable to the Arduino board.

PROGRAMMING

Step 1: Open your Arduino IDE. See how to set up here: Getting Started.

Step 2: Type the following code in your Arduino IDE: const int trigPin = 9;, const int buttonPin = 2;, long duration;, float distance; as shown in the image below.

Wiring diagram

Step 3: Type the following code in your Arduino IDE inside the void setup() pinMode(trigPin, OUTPUT);, pinMode(echoPin, INPUT);, pinMode(buttonPin, INPUT_PULLUP);, Serial.begin(9600); as shown in the image below.

Wiring diagram

Step 4: Type the following code in your Arduino IDE inside the void loop() if (digitalRead(buttonPin) == LOW) {, digitalWrite(trigPin, LOW);, delayMicroseconds(2);, digitalWrite(trigPin, HIGH);, delayMicroseconds(10);, digitalWrite(trigPin, LOW);, duration = pulseIn(echoPin, HIGH);, distance = duration * 0.0343 / 2;,Serial.print("Distance: ");, Serial.print(distance);, Serial.println(" cm");, delay(100); } as shown in the image below.

Wiring diagram

Uploading the code

Step 1: Save your code. See the Getting Started section

Step 2: Select the Arduino board and port. See the Getting Started section

Step 3: Upload your code.

The measured distance is displayed continuously in the Serial Monitor while the button is held down.

CONCLUSION

This project helps learners understand how to combine multiple components with Arduino to create more complex interactive systems and automation solutions.