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Old 25th Mar 2006, 6:46 am   #15
YC-156's Avatar
Join Date: May 2005
Location: Aarhus, Denmark
Posts: 281
Default Re: An interesting magic eye substitution

Originally Posted by Kat Manton
Hmm... a circular array of the very small surface mount 'chip' LEDs driven from some sort of microcontroller (there are some with an ADC) programmed to PWM the last LED lit. So, rather than a step change from one LED to the next you get a gradual increase in brightness before the next one lights...
That is my idea as well, though you can actually do better than that once you have added the microcontroller. Spent some time yesterday researching this, and it is definitely possible to do on a DIY scale. I even got as far as running a SPICE simulation of the PSU circuit, as that seemed the largest stumbling block. Turns out it isn't. [1]

My intention is to use 2,5x5mm rectangular green LEDs, 32 in total, filed or grinded into shape so they can be arranged in a circle a bit less than 25mm in outside diameter. That would provide a much more even light field compared to the original.

Frank N.

[1] The original PSU circuit referenced at the start of this thread will not do IMHO, as it will force a non-trivial DC component through the mains transformer.
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