Intro To Charlieplexing


[sixerdoodle] sent us this nice firefly project that serves as an intro to charlieplexing. We’ve mentioned charlieplexing before, in our LED Life post and the Breath Controlled LED candles post. This project is quite simple and focues mainly on how to make a charlieplexed circuit work.

The goal was to create a tiny firefly bottle with SMD LEDs and as few wires as possible. In the video, after the break, it is hard to tell just how small this thing is until we see the battery. There are clear directions and fantastic pictures detailing exactly how to set up a charlieplexed circuit with 6 LEDs.


Great job [sixerdoodle], thanks for sending it in.

4 thoughts on “Intro To Charlieplexing

  1. Why use such a (physically) large CPU, when there’s 8-pin soic versions around?

    Second, there’s a “bug” in the schematic (and the build) – all GND and VCC pins on the CPU must be connected. Even the AVCC (even though no ADC is used). Read ALL of the datasheet next time.

    But nice project. Really small bottle!

  2. Some improvements would be to use magnet wire (if hes worried about shorting), a smaller IC like JB said, and a hearing aid battery so the whole thing can go into the bottle. You totally loose the firefly effect with that coin cell.

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