PIR Sensor and Relay Switch to turn on a Light

Ever wonder how a motion detector is used to turn on a light? Take a look at this graphic (made with Fritzing). It shows the circuitry that uses an STM32F103C8T6 microcontroller to control a PIR sensor and relay switch to turn on a Light.

PIR Sensor and Relay Switch to turn on a Light

Get the Fritzing source code for the above image HERE (in case you would like to modify it).  Shown below is the code for the STM32F103C8T6 microcontroller to be used in the Arduino IDE.

When motion is detected by the sensor, the relay is turned on which completes the mains circuit. Then, what ever is connected to the relay (like a light) is turned on. The motion detection is also shown by turning on the led and logging to the serial port.

To use this code in a practical situation, remove the serial port messages and change the length of time the relay switch is on.

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