This alarm is designed to sound its Siren only once. That is - when the alarm is activated - the Siren will sound for a preset length of time. Then it will switch off and remain off. The alarm will not re-activate. The basic circuit has a single zone with independently adjustable Exit and Entry delays. The zone will accommodate the usual types of
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normally-open and normally-closed input devices - such as pressure mats, magnetic-reed contacts, micro switches, foil tape and PIRs. A range of Expansion Modules allow you to add any number of Instant Alarm Zones, Personal Attack Zones and Tamper Zones to your system. There`s also an Untimed Output Module. It will keep an internal sounder, strobe-light, lamp or whatever going after the siren has stopped. The alarm may be operated by a simple hidden two-way switch - such as a light switch. If you want more security - you can use a key switch - or one of a number of code operated Keypad Switches. Before you set the alarm - make sure that the building is secure - that ALL of the Green LEDs are lighting - and that the Yellow LED is off. If the Yellow LED is lighting - there`s a fault in one of the zones - and THE ALARM WILL NOT SET. Depending on the setting of R9 - when you move Sw1 to the "set" position - you have up to about a minute to leave the building. When you return and open the door - the Buzzer will sound. Depending on the setting of R8 - you have up to about a minute to switch the alarm off. If you fail to do so - the Siren will sound. Depending on the setting of R14 - the Siren will sound for up to about 20-minutes. Then it will switch off - and remain off. Of course - you can stop the noise at any time by moving Sw1 to the "off" position.
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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