The schematic for this project flows naturally from left to right. Beginning at the antenna and the regenerative receiver front-end, then flowing through the amplification stages and then into the 555 timer. This is a very common regenerative receiver front-end that you can find in circuits all over the web. I tailored the parts used to what I ha
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d laying around, generally you can tweak part values a little bit, with the exception of L2 and C2 which are your tuning circuit (tank circuit) for 27. 145 MHz. Two amplifier stages exist in the middle of the schematic. They are used to `rail` the signal back to its square-wave digital form of either +5v or +0v. I`m pretty sure that these amplifiers could be tweaked to get better performance, however the current design should work well enough for our requirements. The amplified signal makes its way to the 555 timer in the form of its original square wave where this 555 timer uses the voltage detected with internal comparators to create an output that turns on the green LED. The board layout for this project was done in a similar way as the schematic. The front-end receiver can be found on the top left side of the board, then the amplifier stages on the top right and finally the 555 timer and our output LEDs at the bottom right side. Just like with the transmitter, it`s pretty important to have a ground plane for the receiver to act as a better antenna and keep extra noise out of the circuit. A solid ground plane would be very ideal, however for simplicity`s sake we`ll use a chopped up one with traces. I just chose a nice thick width that would transfer over nicely when building the PCB, however smaller trace widths seem to be a better choice when designing RF circuits. but at these low frequencies I don`t believe there will...
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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