A wireless color-changing decoration project

Posted on Feb 7, 2014

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

A wireless color-changing decoration project
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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...

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