The conception of this project is directed to the study of the environment response due to a human action. Based on that subject, an environment was prepared with several visible rays of laser. If one of theses rays is interrupt (eg. someone crosses it), an alarm will be triggered. Therefore, the space of the environment is sensible to the presenc
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e of people. The reason to develop the power source is to replace the laser beans batteries - which don`t have autonomy greater than a couple hours - and also to feed the trigger circuit (see circuit diagram on figure 1). There are two different outputs. One output is stabilized, with DC 5 V and 5 W maximum power. It has the purpose to feed the laser beans. The 7805 voltage regulator is the one that best suits to the lasers connections, because it`s voltage output is 5 VDC, while the beans need 4. 5 V. The difference of the voltage will be solved through the insertion of a resistor in series with each bean. This experiment will have 4 laser beans, fed by the 5 V power source. Each laser bean works with a 4. 5 V voltage and 20 mA current. Therefore, using the Ohm`s law, follows: The alarm circuit consists on a LDR sensor (Light Diode Resistor) that operates as a trigger of the BC327 transistor. If the ray of laser stops falling upon the LDR (eg. a person or an object has crossed the laser ray), it will make the transistor enter on its conducting procedure. If the transistor starts conducting, it will energize the relay. The relay has an electric seal that keeps it energized even if the transistor stops conducting. The siren is connected through the relay to the 12V power source, therefore, if the relay is activated, the alarm is triggered. The project will have 13 mirrors, with dimensions of 50x50 mm and transparency equal...
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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