PIR SENSOR BASED AUTOMATIC LIGHT / ALARM
Whole world is concentrating on energy saving because energy saved is energy produced. Different methods are taking place to reduce power consumption. CFL and LED based light systems are replacing conventional incadence lamps. PIR sensors are a boon in the field of saving energy. PIR sensor based lights are fitted in the areas where parmanent light is not necessary e.g. porch, corridors, stair cases etc. Corridors and staircases need light only when some one passes by there. So, there is no need to keep lights on whole day or night. Lights get on only when some one comes under these areas and gets off after few seconds of leaving the area. This saves a major part of energy. Energy used is very little as compared to energy used in keeping lights on whole day.
Making a PIR sensor light is not a tough task due to the availability of ready made PIR sensor modules. These modules can be wired with few components to get a light system. Any one having even little knowledge of electronics and soldering can make this type of light within minutes.
Here is the step to step procedure to make a PIR based automatic light.The same system can be used as an alarm. Alarm gets activated as soon as some one enters in the area where alarm system is fitted.Components required are low cost and easily available.Components required:
1. PIR sensor module
2. Transistor BC 547/548
3. Diode IN 4007
4. L.E.D. 5 mm, Red
5. Relay 5 V DC (preferably sealed type miniature)
6. P.C.B. General purpose
7. Connector 3 pin ( optional)
8. Power supply 5VDC (mobile charger may be used)
9. Misc. Connecting wires, enclosure,bulb holder etc.
CIRCUIT DIAGRAM FOR OPERATING A BULB OR CFL :
PROCEDURE :
1. Take a piece of general purpose P.C.B. and make a cut in it such that PIR sensor should pass through it.
2. Fix the module on the PCB using thread or using hot gum
3. Note pins of PIR sensor module. Plus (+) and Minus (-)
are written on the PCB of module in very small size. Generally, left pin
is (-), right one is (+) and middle pin is output.
4. Connect a 3-pin female connector to the male connector of the module. Or remove the connector of module and directly solder wires on the PCB using 10 W pen type soldering iron.This will make the system compact.
5. Solder other components on the PCB according to the given circuit diagram and as shown in the photographs.
6. Make two cuts in the enclosure, one for PIR sensor and other one for LED.
7. Fit PCB in the enclosure. Take out power supply and relay contact wires.
8. Connect 5V supply to the supply wires and wait for about one minute so that sensor get ready
TESTING:
TESTING:
After one minute wave your hand in front of the sensor. LED will glow and sound of relay operation will be heard. After few seconds LED will go off depending on the pre-setted time. This time can be changed using a preset available on the PCB of sensor module. One more preset available is used to change the range of sensor.
