Motion detector with light & mp3 player

How to make a motion light detector with mp3 player

In this project, I‘m going to build a simple motion detector circuit with a mp3 player.
The idea is based on: If somebody passes through the doorway, the circuit should detect it and switch the light on and play  a music.
The main component that I used is a microwave radar sensor and a small mp3-player.

Required Materials

  • A Microwave/radar motion sensor  (The sensor can detect motion up to 5 meter away and his angle is about 360 degrees.)
  • A 5V power supply (I used an universal phone charger)
  • A Traic BT139 with a OptocouplerMOC 3021
  • A BC547 Transistor (to power mp3-player and optocoupler)

How Does it Work?
The motion sensor and mp3-player need between 5V of power to operate, therefore I used a 5v USB phone charger.

On sensor pin 2,4 receives the  5v DC voltage. The pin 3 is the Output of the sensor.
When motion is detected, this output goes high to 3.3V.  This 3.3v output can power a LED with 20mA but this current is not enough to turn on the optocoupler.

To handle this problem, I connected the output of sensor to the base of the transistor BC547. This transistor feeds the mp3-player and the input of optocoupler.
The output of Traic can turn a 30W 220v AC LED light on.

In order to extend the light-time,  I soldered a 33nf to the C-TM contacts on the sensor. It extended the time more than 45 sec.

May you do NOT necessary to develop your own switch.
Currently who wants can buy the device from the Chinese resellers for about 3$. It’s can switch up to 30 watts.
Microwave Radar Sensor Switch


The max distance range of the radar is about 7m.
The device have two potentiometer for adjustment of sensitivity and time.
This range can be limited to 2m by adjusting the sensitivity potentiometer.

Radar sensor can detect a moment in behind a wooden door and if the room is smaller than minimum range (and that is my case)  than the light will be on by any movement behind the door.



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