SI is external key switch. The alarm allows a 0- to 45-s delay after SI is operated before the circuit is armed. During this per..
This circuit uses a NE555 timer and CD4020B. When +12 Vdc is applied to the circuit, the output of ..
Trembler (motion activated) switch sounds the alarm for 5 seconds. Then it goes off..
Removing R1 or R2 from the circuit the potential thief breaks a hidden wire that connects R1 to +12 V and R2 to ground)..
Alarm triggers on after a 13 second delay and stays on for 1-1 Vfe minutes. Then it resets automatically..
In operation. the alarm circuit allows a 0-47 second time delay, as determined by the Rl/Cl combination, after the switch is armed to allow the vehicle"s motion sensor to settle down. This allows you time to get a bag of groceries out of the trunk and not have the hassle of juggling the groceries and the key switch at once. During the time delay, half of LEDl, which is actually a single, bi-colored, three-legged common cathode device, lights green. At the same time,.....
An auto horn will work as a speaker of limited audio-frequency range. This circuit uses a 555 timer as a..
The circuit automatically turns on when the car is turned off. It gives you a variable time to get out and lock..
See (a) for the timing information for the alarm circuit in (b). When leaving your vehicle, flip the arming switch and close the door to arm the device. Subsequent opening of an entrance triggers both timers. After the expiration of the entry delay timer, the alarm sounds for a time determined by the second timer. The value of R should be less than 1 KO. If you use an incandescent lamp instead of a resistor, you get an extra function-an open-entrance indicator. ..
This alarm gives a 15-20 second exit and entrance delay. After being triggered, the alarm sounds for five minutes and then shuts off..
The aim of this project is to use wireless technology to intimate the owner of the vehicle about any unauthorized entry. This is done by sending an auto-generated SMS to the owner. An added advantage of this project is that the owner can send back the SMS which will disable the ignition of the vehicle. As the crime rate is going up, security system for vehicles is extremely essential. In this proposed system if someone tries to steal the car, the microcontroller gets.....
The alarm is "set" by opening Sw1. It can be any small 1-amp single-pole change-over switch - but for added security you could use a key-switch. Once Sw1 is opened you have about 10 to 15 seconds to get out of the vehicle and close the door behind you. When you return and open the door the buzzer will sound. You have 10 to 15 seconds to move Sw1 to the "off" position. If you fail to do so, the siren will sound...
This FM radio-controlled anti- theft alarm can be used with any vehicle having 6- to 12-volt DC supply system. The mini VHF, FM transmitter is fitted in the vehicle at night when it is parked in the car porch or car park. The receiver unit with CXA1019, a single IC-based FM radio module, which is freely available in the market at reasonable rate, is kept inside. Receiver is tuned to the transmitter's frequency. When the transmitter is on and the signals are being received.....
This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. The circuit is designed to use an electronic Siren drawing 300 to 400mA. It`s not usually a good idea to use the bike`s own Horn because it can be easily located and.....
This circuit features exit and entry delays, an instant alarm zone, an intermittent siren output and automatic reset. By adding external relays you can immobilize the vehicle and flash the lights. One of the inputs is connected to the vehicle`s existing door-switches. This provides the necessary exit and entry delays. It`s usually sufficient to connect a SINGLE wire to just ONE of the door switches - they`re generally all connected in parallel with the return through the.....
The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Without its terminal blocks, the board is small. Ideally, you should try to find a siren with enough spare space inside to accommodate it. Fit a 1-amp in-line fuse close to the power source. This protects the wiring. Instead of using a key-switch you can use a hidden switch; or you could use the normally closed contacts of a small relay. Wire the relay coil.....
This circuit will flash a bright LED 5000mcd as an intention getting device or fake car alarm...
This is a simple - easy to build - transistor based motorcycle alarm. It`s designed to work at 12-volts. But - if you change the relay for one with a 6-volt coil - it`ll protect your "Classic Bike". The standby current is virtually zero - so it won`t drain your battery. The Support material for this alarm includes a detailed guide to the construction of the circuit-board, a parts list, a complete circuit description and more...
The alarm is "set" by opening Sw1. It can be any small 1-amp single-pole change-over switch - but for added security you could use a key-switch. Once Sw1 is opened you have about 10 to 15 seconds to get out of the vehicle and close the door behind you. When you return and open the door the buzzer will sound. You have 10 to 15 seconds to move Sw1 to the "off" position. If you fail to do so, the siren will sound. The output to the siren is intermittent - it switches on and.....
This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. Ron has used my Asymmetric Timer as the basis for his design...
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