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Electronic Siren – Circuit Schematic
Electronic Siren
This is Electronic Siren circuit diagram. The sound produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors i...
Electronic Door Release – Circuit Schematic
Electronic Door Release
Electronic Door Release Circuit This circuit is designed to operate an electrical door-release mechanism - but it will have other applications. Enter the four-d...
Electronic Door Lock Security Key – Circuit Schematic
Electronic Door Lock Security Key
This is the circuit diagram electronic door lock security key system. It means that this security system circuit is the combination of pressed key itself (not t...
Door Knob Touch Alarm – Circuit Schematic
Door Knob Touch Alarm
This is door knob touch alarm for your home security purpose. The alarm will be activated when someone touch the metal door knod. This circuit wont work on full...
Car Alarm Simulator – Circuit Schematic
Car Alarm Simulator
This is a car alarm simulator which using the LED as a simulation output. This simple circuit can tell you whether your car is running or not by detecting the v...
A Simple Transistor Based Motorcycle Alarm – Circuit Schematic
A Simple Transistor Based Motorcycle Alarm
A Simple Transistor Based Motorcycle Alarm Circuit This is a simple - easy to build - transistor based motorcycle alarm. It`s designed to work at 12-volts. But ...
A Dozen Small Cmos Alarm Circuits – Circuit Schematic
A Dozen Small Cmos Alarm Circuits
A Dozen Small Cmos Alarm Circuits Circuit Description This is a selection of small self-contained alarm circuits. The main features of each alarm are described ...
A Cmos Based Motorcycle Alarm – Circuit Schematic
A Cmos Based Motorcycle Alarm
A Cmos Based Motorcycle Alarm Circuit This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or ...
A Cmos 4060 Burglar Alarm – Circuit Schematic
A Cmos 4060 Burglar Alarm
A Cmos 4060 Burglar Alarm Circuit This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of ...
Digital Lock Project – Circuit Schematic
Digital Lock Project
EncoderBit1(LOW) is negated with the hex inverter U5A and sent to the 4-input AND gate U3A along with EncoderBit0(HIGH), the above J-K output (HIGH), and a HIGH...
SIREN GENERATOR CIRCUIT – Circuit Schematic
SIREN GENERATOR CIRCUIT
An adaptable siren generator circuit with a multitude of uses is shown. It is based around a 556 twin-timer chip, IC1. An audio tone is created by one timer sec...
DIGITAL LOCK CIRCUIT – Circuit Schematic
DIGITAL LOCK CIRCUIT
This circuit depends on the entry of a correct sequence code. An incorrect number that is not part of the code causes the circuit to reset. When the correct cod...
SLAVE FLASH TRIGGER – Circuit Schematic
SLAVE FLASH TRIGGER
The SCR is wired across the trigger circuit of the flash gun. Normally, the SCR is off, so the flash gun is able to charge to its trigger voltage. Photo transis...
NOAA WEATHER ALERT DECODER – Circuit Schematic
NOAA WEATHER ALERT DECODER
This circuit detects the 1050-Hz tone sent by the NOAA (National Oceanic and Atmospheric Adminis-tration) Weather radio stations that operate from 162. 40 to 16...
ELECTRONIC SIREN – Circuit Schematic
ELECTRONIC SIREN
For normal wailing tone, short D1 and open R2. For fast rise and slow fall in frequency, include D1 and R2. Use of a CD4046B with a diode-RC network as shown pr...
DIGITAL ENTRY LOCK – Circuit Schematic
DIGITAL ENTRY LOCK
A keypad enters a four-digit access code, which is programmed via jumpers on a 24-pin plug-in header and socket. U1 is an LST220, which detects a four-digit seq...
BUG DETECTOR – Circuit Schematic
BUG DETECTOR
This rf detector can locate low-power transmitters (bugs) that are hidden from sight. It can sense the presence of a 1-mW transmitter at 20 feet, which is sensi...
HIGH POWER SIREN – Circuit Schematic
HIGH POWER SIREN
IC1a and IC1b are wired as a slow astable multivibrator and IC1c-IC1d are wired as a fast astable. Both are "gated" types, which can be turned on and off via PB...
SIREN ALARM SIMULATES STAR TREK RED ALERT – Circuit Schematic
SIREN ALARM SIMULATES STAR TREK RED ALERT
The signal starts at a low frequency, rises for about 1. 15 seconds to a high frequency, ceases for about 0. 35 seconds, then starts rising again from a low fre...
AUTO ALARM – Circuit Schematic
AUTO ALARM
In operation, the alarm circuit allows a 0-47 second time delay, as determined by the R1/C1 combination, after the switch is armed to allow the vehicle`s motion...