So you`re either revved up about building one of these for yourself or you`re just reading on because you`ve nothing better to do. I can understand that. So let`s begin with a set of schematics: Don`t be confused by this - it`s your basic 555 timer configured as an astable multivibrator. Its sole job is to provide pulses for the shift registers. T
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hese part values make the thing oscillate at around a kilohertz. Also fairly straightforward. Pin 4 is the Reset pin which should be held high for normal operation. The diode is to support in-circuit programming. Note that the crystal shown is actually a 4 MHz ceramic resonator with its center terminal tied to ground. The resistor allows the shift register to loop its information within itself, so long as the PIC`s pin does not decide to interfere. When it does, however, the PIC`s pin is able to deliver enough current to `defeat` the looping information, thus overwriting it. Returning to a high-impedance state allows the new information to cycle some more. This circuit is repeated for each color. The value of the resistors are chosen to put about 30 mA through each LED, and adjusted to create approximately the same light output for full brightness. For red I chose 220 ohms, and for green and blue 100 ohms. Again, this circuit appears once per color. This is your standard DB9 female connector, viewed from the solder side. This setup ties together the Request To Send and Clear To Send pins, and the Data Terminal Ready and Data Set Ready pins. The resistor is to protect the TX433`s input from the harsh RS232 voltage. The diode makes sure the TX433 never receives reverse voltage. The TX433 is powered by the Data Terminal Ready pin which provides ample current (even from my laptop). You may have noticed that there is a six-pin...
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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