nanoFramework.Iot.Device.Hcsr501 1.2.95

HC-SR501 - PIR Motion Sensor

HC-SR501 is used to detect motion based on the infrared heat in the surrounding area.

Documentation

• In Chinese
• In English

Usage

using(Hcsr501 sensor = new Hcsr501(hcsr501Pin, PinNumberingScheme.Logical))
{
    // detect motion
    bool isDetected = sensor.IsMotionDetected;
}

From the HC-SR501 sample, we can do comething more complete:

GpioController ledController = new GpioController();
ledController.OpenPin(27, PinMode.Output);

using (Iot.Device.Hcsr501.Hcsr501 sensor =
    new Iot.Device.Hcsr501.Hcsr501(17))
{
    while (true)
    {
        // adjusting the detection distance and time by rotating the potentiometer on the sensor
        if (sensor.IsMotionDetected)
        {
            // turn the led on when the sensor detected infrared heat
            ledController.Write(27, PinValue.High);
            Debug.WriteLine("Detected! Turn the LED on.");
        }
        else
        {
            // turn the led off when the sensor undetected infrared heat
            ledController.Write(27, PinValue.Low);
            Debug.WriteLine("Undetected! Turn the LED off.");
        }

        Thread.Sleep(1000);
    }
}

Hardware Required

• PIR Motion Sensor - HC-SR501
• LED
• 220 Ω resistor
• Male/Female Jumper Wires

Circuit

HC-SR501

• VCC - 5V
• GND - GND
• OUT - GPIO 17

LED

• VCC & 220 Ω resistor - GPIO 27
• GND - GND

Result