Why wasting energy by continuously switching on the Washbasin light? Just install this Motion sensor based LED light. When you move towards the Washbasin, the light turns on. It stays on for three minutes and turns off. You can also use this as a Cupboard light. Its power is 6 watts. Cool! No switching is needed and saves considerable amount of energy. Its cost is just Rs. 150.Let us see its working.
Designed and developed by D.Mohankumar
You need the following components
1. PIR Motion Sensor Module – 1
2. 1K Resistor – 1
3. SL 100 ( CL 100 or Bel 100N) Transistor-1
4. IN4007 Diodes – 2
5. 470uF 25V Electrolytic capacitor – 1
6. 9-0-9, 500 mA Transformer – 1
7. 6 LED panel – 1 watt LEDs – 1
How it works?
PIR Sensor Module detects Human motion from a distance of 10 Meters (adjustable) and gives a high output around 3 volts. This high output drives the NPN transistor T1 to light the LED panel. The duration of the high state of PIR Sensor module can be adjusted from 30 seconds to three minutes. The Strip LED has its own 200 Ohms resistor, so no current limiting resistor is needed.
Power supply for the circuit is derived from a 9-0-9 , 500 mA transformer and diodes D1,D2 and the smoothing capacitor C1.
After connecting the PIR Module to the circuit, adjust the presets for range and timing according to the needs. Fix the unit above the Washbasin and connect to the AC lines. If you use a Relay with IN4007 diode in the place of LED panel, you can drive AC bulb.