PDF Manual Simple Siren Circuit Kit

9 Volt Siren Kit — CK1207 A simple 9 volt siren kit with a surprisingly loud output. Uses voltage controlled oscillator; comes with a half-watt 8 ohm speaker. Good as a sound module to attach to an alarm system, etc.

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LPG Gas Leakage Sensor Alarm Project Report

LPG gas is supplied in pressurised steel cylinders. As this gas is heavier than air, when it leaks from a cylinder it flows along floor and tends to settle in low spots such as a basement. This can cause fire or suffocation if not dealt with. Zener diode ZD1 is used to convert 9V into… Read More »

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Light Alarm with Timer 555

Here is the simple and low cost light alarm circuit built using timer IC 555 as the sound generator and a LDR to sense the environment light. This alarm is activated when the light beam on the LDR photocell is interrupted (You can use the light of a flashlight bulb which will make you a… Read More »