Wiring Diagram

This circuit emits a beep and/or illuminates a LED when someone touches the door-handle from the outside. The alarm will sound until the circuit will be switched-off.

Q1 forms a free-running oscillator: its output bursts drive Q2 into saturation, so Q3 and the LED are off. When part of a human body comes in contact with a metal handle electrically connected to the wire hook, the body capacitance damps Q1 oscillations, Q2 biasing falls off and the transistor becomes non conducting. Therefore, current can flow into Q3 base and D3 illuminates. If SW1 is closed, a self-latching circuit formed by Q4 & Q5 is triggered and the beeper BZ1 is activated.When the human body part leaves the handle, the LED switches-off but the beeper continues to sound, due to the self-latching behavior of Q4 & Q5. To stop the beeper action, the entire circuit must be switched-off opening SW2. R3 is the sensitivity control, allowing to cope with a wide variety of door types, handles and locks.

IC 555 Motorcycle Alarm Circuit



Rangkaian Motorcycle Alarm

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. I have used Andy's Asymmetric Timer as the basis for this design.

Rangkaian Motorcycle AlarmSkema Rangkaian IC 555 Motorcycle Alarm

Any number of normally-open switches may be used. Fit "tilt" switches that close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc.

The alarm's standby current is virtually zero - so it won't drain your battery. Once activated - the rate at which the siren switches on and off is controlled by R7, R8 & C4. For example, increasing R7 will make the sound period longer - while increasing R8 gives longer silent periods.

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 disconnected. However - if you choose to use the Horn - remember that the alarm relay is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn, flash the lights etc.

The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Connect a 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the alarm. Exactly how the system is fitted will depend on the make of your particular machine - so I'm unable to provide any further help or advice in this regard.

When you set the alarm - if one of the switches is closed - the siren will sound. This could cause annoyance late at night. A small modification will allow you to Monitor The State Of The Switches using LEDs. When the LEDs are all off - the switches are all open - and it's safe to turn the alarm on


This circuit will energize and de-energize a relay at the push of a button. Any type of momentary action push-to-make switch can be used. Pushing the button once - will energize the relay. And pushing it a second time - will de-energize the relay

Rangkaian Toggle Switch Skema Rangkaian Toggle Switch

I've drawn the circuit with a single pole relay. But you can use a multi-pole relay if it suits your application. Only one half of the Cmos 4013 is used. So you could construct two independent toggle switches with a single IC. The circuit will work at anything from 5 to 15-volts. All you need do is select a relay with a coil voltage that suits your supply.

The LED provides a visual indication that the relay is energized. In effect - it tells you whether the switch is on or off. It's not necessary to the operation of the circuit. If you wish you may leave out R3 and the LED.