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on the high end and preserve the RSSI linearity. The RSSI signal is a current source that flows through R6 to establish a voltage at pin 5 of U1;the RSSI output voltage is a function of the input SPL. Capacitor C10 removes high-frequency components. The slope of the RSSI line is nominally 0. 084VCC/10 dB. Op amp U2-b is configured as a non-inverting voltage buffer with a gain of 1. 2; multiplied by the RSSI slope, this produces a slope of 0. 1VCC/10 dB. The display, DISP1, is a 10-bar LED that is used to indicate sound level in 10-dB increments from 30 to 120 dB(A). The display is driven by an LM3914linear bar-graph driver, U5. The internal voltage regulator of U5 functions by establishing a constant current through R15 because the voltage between pins 7 and 8 is maintained at 1. 25V. The resulting voltage at the emitter of Q2 is about 5V, which powers U1, U3, and the internal voltage-divider string of U5 at pin 6. Each segment of the display will increase by 10 dB, independent of the exact magnitude of VCC While the slopes of the display driver and the RSSI signal are the same, they might not have the sanit offset. For that reason, an LM334, U4, is used to source a constant 10- A current through R17 to generate a fixed off-set voltage on top of the composite RSSI voltage at the output of U2-a. By adjusting the value of potentiometer R17, differences in microphone sensitivity can be accommodated so that the display reads...
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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