Here is an LDR based movement detector for day time use. It is highly useful in shops, banks etc to confirm the entry and exit of persons. It uses two LDRs and the popular timer IC555.
You can easily attend a Telephone call in darkness using this White LED lamp. When the Telephone rings, the White LED flashes in sympathy with the rings. So sufficient light will be available to locate the phone to attend the call. This circuit is provided to explain the working of Optocoupler.
Continue reading “Telephone Locator. Sensor Circuit.3”
This is a highly sensitive broken beam alarm active both day and night. It uses invisible Infrared rays to inhibit the working of alarm generator. When the IR beam breaks, by a moving person, alarm will be activated. Ideal circuit as door protector.
This LDR based alarm can be used as wake up alarm. The Alarm turns on in the morning automatically and turns off only when manually switched off ,so you will have to wake up. It is a simple LDR based light sensor circuit.
Here is a simple Automatic Porch light controlled by an LDR and Triac. It automatically turns on in the evening and turns off in the morning. The circuit is too simple and uses Mains voltage directly. It can be enclosed in a plug in type adapter box.
Continue reading “Automatic Porch Light. Utility Gadget.14”
Now you can light your home premises with this Automatic lamp. It turns on in the evening and turns off in the morning. No switch and no manual operation. So it can light the premises even if the inmates are not in home. A simple security measure.
Protect your LCD TV from Over voltage. After a power failure or during lightening, very high voltage surge develops in the Mains line which is the major cause that damage TV. Plasma and LCD TV are costly devices and uses SMPS type power supply. Use of Stabilizer is recommended for LCD TV. This low cost circuit can do the job of protection very well. When the mains voltage increases above 250 volts, it will drop most of the voltage around 100 volts passing through the load and the condition remains as such till normal voltage level attains.