Pyroelectric Fire Alarm

Ordinary fire alarm circuits uses diode sensors to detect fire presence. But a pyroelectric fire alarm circuit described here is an ultra-sensitive fire sensor that uses direct piezoelectric property of an ordinary piezo element to detect fire.

Water Level Indicator With 7-Segment Display

Circuits available for indicating water level is usually consist of LEDs to indicate the liquid level. But this circuit uses a 7-segment LED display instead of normal LED's for numeric display of water level.Moreover, a buzzer is used to alert you of water overflowing from the tank. The circuit shows the water level by displaying L, H and F for low, half and full, respectively. You can use this circuit for water tank motor control or a stand alone circuit.

Infrared Burglar Alarm Using Remote control

There are so many circuits available for infrared Burglar alarm but transmitter  section of these burglar alarm circuits are complicated and you may have assemble it yourself. But here is burglar alarm circuit that uses the ordinary DVD remote as the transmitter. So not only the cost also the man power will be saved.  You only need to press and hold any switch of the remote control to allow flow of IR signals to outside. This can be done by grafting any key of the remote using insulation tape. This house alarm is very useful and doesn't require much components.

Water Activated Sensor Alarm Using 555

Here is a circuit diagram of water activated sensor alarm using 555 IC.We may use this circuit for the following applications:

•  Water leakage detection from water tank and can be used as a water leak alarm
•  To detect presence of rain outside the room
•  Do detect the presence of moisture or water molecules on a substance
•  Used as detector of water in water overflow alarm