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 super-cheap 14-segment displays
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By: Anonymous: Dr. Memory () on Wednesday, September 12 2007 @ 11:00 AM PDT (Read 6245 times)  
Anonymous: Dr. Memory

(as of 9/12/07) Electronics Goldmine is selling 20-piece tubes of IEE 3585R dual 14-segment displays for $15! That's only $0.38 per character!

look here:

The catch? They're matrixed 7x2 (per digit), so you have to "charlieplex" them. But hey, that's cool, because that means with just an attiny2313 we should be able to do 6 characters with no extra parts and still have enough pins for two buttons.

You could do a nice 6-digit clock or scrolling display with very few parts.

I wonder, would you have enough time for refresh if you used a 32 khz watch crystal?

If anyone is interested I have figured out the pinout on this part. I could not find a datasheet online for it.


By: Windell (offline) on Wednesday, September 12 2007 @ 02:28 PM PDT  

That is an excellent price. A 32 kHz crystal *might* be adequate if you're clever with your source code. I try to keep my refresh rate above 500 Hz; lower than that tends to bother me.

The only thing that I would worry about is that these displays are probably not very bright-- running each segment with low duty cycle may not make the overall display bright enough to read, depending on circumstances-- but, you'll have to be the judge of that.

(I have worked with some 17-segment displays in the past that were not really readable if you multiplexed them at all-- they had to be driven in parallel.)

Windell H. Oskay

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By: Anonymous: Dr. Memory () on Friday, September 28 2007 @ 10:47 AM PDT  
Anonymous: Dr. Memory

You're correct, they're not super bright. I've only gotten as far as figuring out the pinout. I don't know how they look when multiplexed. Can't be too awful since that's the only way they can be used.



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