Blinking Eva

Since it’s suddenly, out of nowhere, christmas time again, and since christmas is traditionally the time to build blinking somethings, i decided to publish this. Long ago – well, actually last year – this as a christmas present for my girlfriend Eva.

What does it do? Nothing useful. You plug it in, and the various LEDs blink wildly, one letter at a time, two letters at a time, all on, all off.

I’m not particularly proud of this board. The matrix design is just painful to route on an one-sided PCB, so please don’t do it, especially if you plan on doing something similar with more than three letters. I’d like to use something like the AS 1110 for something similar, but there are just no distributors for those chips.

Nevertheless, if you know someone named Eva who likes to solder a bit or who just likes blinking things, this might be a nice present.

Things to take care of:

  • Energy source: I used some old wall wart for this. The used 7805 is quite robust, but not very efficient. Use something between around 8 V to 15 V, and check the polarity, which is unfortunately not standardized.
  • Since the LEDs are driven only 1/4th of the time, you can in theory use higher currents than if driven all the time.

link to photos/elektronik/blinking-eva/assembly-diagram.png link to photos/elektronik/blinking-eva/rendering.png link to photos/elektronik/blinking-eva/schematic.png



filetype blinking-eva/blinking-eva-board.pdf (249.03 kiB, 2008-12-06)
filetype blinking-eva/eagle-files.tar.bz2 (54.42 kiB, 2008-12-06)
filetype blinking-eva/firmware.tar.bz2 (3.75 kiB, 2008-12-06)
filetype blinking-eva/manual-german.pdf (1.28 MiB, 2008-12-06)

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