Movement Detector. Sensor Circuit.4

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.

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Telephone Locator. Sensor Circuit.3

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.
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IR Beam Alarm. Sensor Circuit.2

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.

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Morning Alarm. Sensor Circuit.1

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.

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Automatic Porch Light. Utility Gadget.14

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.
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