This circuit can protect AC appliances. When the AC voltage in the mains increases above the set level , say 220 volts, relay triggers and breaks power from the appliance. Reconnects the appliance when the power returns normal.
Beep once when power fails. 12 volt relay is used as a switch. When power is available, relay pulls and capacitor charges via diode D1 and NO and Common contacts of relay. When power fails, relay turns off and capacitor discharges via Common and NC contacts and buzzer. Buzzer gives a short beep at that time. If more timing for beep is needed, connect one … Continue reading Simple Power Failure Alarm
The Project implementing is a Gas leakage alarm system that senses the leakage of LPG from Gas cylinder or Gas stove and gives a warning alarm. Its further modification can be automatic cut off the electricity system in the home and also a battery operated exhaust fan to remove the leaked gas from the room.
This project is based on the PIR Motion sensor to detect human movement and alarm generation as a surveillance system for home and office. The circuit sends the alarm sound wirelessly to the interior of home and also switches on the outdoor lights when it detects a human movement. Continue reading “PIR sensor based home surveillance system”
It was a big problem in my house that, sometimes the Water heater left on for many hours after the use. It has a Thermostat to cut off but when the water cools, again it switches on. This causes hike in electricity bill. Finally I found a solution. Just connected a Timer based alarm with the heater AC socket so that it will also switches on when the heater turns on. After 30 minute, it gives a loud alarm to remind that the heater is On. Alarm continues for another 30 minutes or till the heater is switched off. So that alarm reminds to switch off the water heater. This can be used for Electric Iron also.
Make this simple White LED emergency lamp using few components. It can be plugged into the AC socket and it turns on at the moment when power failures. It emits cool white light in the room which is sufficient even for reading purpose. It is powered by a 4.5 volt rechargeable battery and uses 1 watt White LED.
When we use Triac and LDR to make Automatic Lights, a major problem arises . Lamp starts flickering during the light transition period in the evening and morning. Lamp fully turns on only when there is complete darkness and turns off only when day light is full. This simple design solves the problem. Light instantly turns on / off without any flickering. You can drive CFL, LED bulb etc which turns on automatically around 6 pm and turns off around 6 am. See the simple design. Continue reading “Flicker Free Automatic Light”