The goal of this project is to design and build a full duplex digital fiber optic voice link over a length of 50m at minimum data rate of 64 kbps. The cores of this project are the designs of LED driver and photo-detector circuits. From the preceding circuit diagram, it only shows one side of the circuit. The other side of the circuit is just a du
Click here to download the full size of the above Circuit.
plicate from this circuit. The only part that you need to notice is the output of the LED driver is connected to the photo-detector circuit on the other side, and vice versa. The condenser microphone is biased with a 9V supply and a 4. 7k ohm load resistor. Recall that electret condenser microphone need biasing because of the built-in FET amplifier inside the microphone capsule. The AC-coupling capacitor is used as a high pass filter to block the DC offset, so the microphone signal is AC coupling. Since this audio amplifier is built specifically for audio signal, so this amplifier can not be used as any other general-purpose op-amps. This circuit here is used from the datasheet, which gives a gain of 50. In case of signal distortion, a 10K potentiometer is used to control the amplitude of the input signal. Again, the 220uF AC-coupling capacitor is used to block the DC offset. This second-order sallen-key low pass filter is designed to have a 3. 5kHz cut-off frequency, which bandwidth is sufficient for human speech. We used this specific filter over the typical RC filter because we obtain a sharper roll off and much less noise. The 256kHz clock signal is generated by a signal generator, and it is mainly used as a master clock and bit clock for the audio encoder. The 8kHz clock signal obtained by using the SN54HC393 dual 4-bit binary counter, which divided the 256kHz signal by 32. This 8kHz clock signal is used to synchronize...
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.....
characters left: