Radar System Using a BBC Micro:bit

Here is a simple radar system using a BBC micro:bit, an ultrasonic sensor (HC-SR04), and optionally a servo motor to rotate the sensor.

🔧 Components Needed

🧠 Working Principle

1. Ultrasonic sensor sends sound waves.
2. It measures the time for echo to return.
3. Distance is calculated based on speed of sound.
4. Optional: The servo motor rotates the sensor to scan an area.
5. Micro:bit displays distance on LED screen, or sends data to a graphical interface (like a radar screen on a PC via serial).

🔌 Circuit Diagram

Without Servo:

• VCC (HC-SR04) → 3V (micro:bit)
• GND (HC-SR04) → GND
• Trig → Pin 0
• Echo → Pin 1

With Servo:

• Servo signal wire → Pin 2
• Servo VCC → External 5V source (important!)
• Servo GND → Common ground with micro:bit

💻 MakeCode (Blocks or JavaScript)

Here is a basic version using MakeCode JavaScript:

let distance = 0

basic.forever(function () {
    pins.digitalWritePin(DigitalPin.P0, 0)
    control.waitMicros(2)
    pins.digitalWritePin(DigitalPin.P0, 1)
    control.waitMicros(10)
    pins.digitalWritePin(DigitalPin.P0, 0)

    let duration = pins.pulseIn(DigitalPin.P1, PulseValue.High)
    distance = duration / 58

    basic.showNumber(distance)
    basic.pause(500)
})

Note: Use extension for servo motor if you add one:
Go to Advanced > Extensions > Search for servo.

PYTHON CODE

from microbit import *
import time

def measure_distance():
# Trig pin LOW
pin0.write_digital(0)
time.sleep_us(2)

# Trig pin HIGH for 10us
pin0.write_digital(1)
time.sleep_us(10)
pin0.write_digital(0)

# Echo süresini oku
duration = pin1.read_pulse(PinValue.HIGH)

# Mesafeyi cm olarak hesapla
distance = (duration / 2) / 29.1
return distance

while True:
distance = measure_distance()
display.scroll(str(round(distance)) + “cm”)
sleep(500)

🖥️ Optional: Radar Display on PC

To visualize data on a radar-style interface:

• Send angle + distance via serial (USB).
• Use Processing or Python with matplotlib/pygame to draw radar lines.

📚 Learning Outcomes

• Distance measurement using ultrasonic sensor
• Understanding pulseIn() for echo timing
• Data visualization techniques
• Optional: Servo motor control + angle-distance mapping