With the quickening of the modern rhythm of life, the frequency happening in traffic accident is increasing too, in order to improve the safety that the car runs, this text introduces the mechanically controlled car anticollision alarm system of a one piece. This device combines real time control and data processing function of the one-chip comput
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er with ultrasonic range finding technology, sensor technique, can measure the car in distance and car speed between rear obstacle and car while running, reveal the distance through the digital display device, and is given out the warnings according to the distance situation by the voicing circuit. The principle of ultrasonic range finding is, launch, meet the obstacle reflected back wave through measuring supersonic wave constantly, thus measure and launch supersonic wave and receive the time difference T of the back wave, then find the distance S =C * T/2, among them, C is the ultrasonic wave speed, it is 344m/s to fetch at room temperature. After the velocity of sound is confirmed, so long as measure supersonic wave for round time, can try to get the distance. The measurement of the car speed is realized by Hall`s integrated sensor. Namely, link the input shaft equipped with rotary table of the permanent magnnet with the axis of rotation of the wheel, when the wheel rotates, the rotary table is thereupon turning, at this moment, the permanent magnnet on the rotary table will pass Hall`s integrated sensor, thus get a magnetic signal in the input end of Hall`s integrated sensor, rotate if rotary table ceaselessly, Hall integrated sensor can output rotational speed signal. We can say, the measurement of the car speed is actually the measurement of the frequency to the rotational speed signal. AT89C2051 is a low power...
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....
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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.....
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to....
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