The Nutchip decodes the signal, differentiating between immediate and delayed sensors (aside from true remote control signals used for switching the circuit on and off). As for all radio-based designs, always remember that a good radio receiver cannot replace a good antenna. The circuit works well with an home made antenna (straight insulated wire), should your budget forbid
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a commercial one. Wireless sensors aside, our schematic provides also inputs for wired sensors. Such sensors are treated as normally closed contacts, that break when someone enters their range or opens a door or window. It is often the case that they provide a second anti-tamper contact, which breaks if you open the case or attempt a sabotage. Therefore we need two inputs: one for connecting anti tamper and immediate contacts and another one for connecting the delayed contacts. The "immediate" input is connected to the Nutchip pin IN1, and the "delayed" on to pin IN2. As the wires are usually long enough to collect any sort of noise and interference, a couple of identical networks provide quite an energic cleanup and clipping on the input signal before it arrives to the chip. These networks are built around R7-R9-C5-DZ2 and R6-R8-C4-DZ1 respectively. All of the output are connected to a LED diode (DL1, DL2, DL3, DL4), in order to display the status of the main board. A siren is connected to the fourth output, through RELAY1. As this circuit is designed for uninterrupted service, brown-outs are a possibility that cannot be excluded. A brown-ut is a big decrease in the mains voltage level that does not end in a black out. Brown-outs are dangerous for electronics devices, because it can result in improper or partial reset with impredictable consequences. This is why whe have added IC2, a special voltage detector and RESET...
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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