Sunday, May 19, 2013

Form vs Function

THE LOOK

The first order of business is to upgrade the 'look' of the PEGS. The original PEGS are big, boxy, and as some people put it, UGLY. We want this pair to look good with the lights on or off. After several designs and a lot of tweaking the following outline was chosen.
They will maintain the same shutter shade design featuring large horizontal slits for looking through them. The nose has also been changed slightly to allow room for a cushion so the glasses wont tire your nose out.

THE LIGHTS

With the frames shaping up, it's time to consider what LED to use, how to drive them (power them) and what arrangement to place them in. One of the most popular suggestions by you was to make them brighter, so a new driving technique is needed. Last time the micro-controller (brain) directly powered the LEDs with the help of a single 595 shift register (a simple chip that allowed us to power more LEDs). With this setup each LED was receiving about 5mA, 1/16 of the time (numbers that mean things). The LEDs used can take twice that much power so a new technique is needed to drive them. MOSFETs (high power switches) and constant current shift registers (like the 595 shift register about but WAY better) will will work and allow for more LEDs. With more LEDs possible the question is how many is too many? I did some budget analyses and found 20 or 24 delivered the most bang for the buck. A quick rendering in my favorite CAD program, MS Paint :) and it was easy to see 24 is much better.
Old PEGS on top; 24x7 middle; 20x7 bottom; Proper aspect ratio maintained.

Have something to suggest? Please leave it in the comments! Also don't forget to share us on facebook :)

6 comments:

  1. 20 and 24 seems the best :) The 24 is even better if the price allows it :)

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    1. Thanks for the feedback. Oddly enough its cheaper to do 24 than it is to do 20.

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    2. Then the choice is quite obvious right? :) Perhaps the 24 are less bright? Or maybe you have no vision at all if you take 24? You still need to see something through the glasses huh ;) I actually hope it will not obstruct my view at all. :)

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    3. Yes 24 was the obvious choice. The LEDs shine away from your eyes so you see almost no light from them. I sometimes don't even know if they are on unless I light something up, like putting my hand in front of them :)

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  2. Wow you are a fast responder! Love it! :) anyways the only downside I can think of them would be battery life for the 24 vs the 20 one, but that is pretty much it. They should at least last for 10 hours or so, most parties I am attending are from 21:00 till 7:00 so that's a long time ;)

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    1. I am passionate about this project :). The math shows 5 hours at full brightness w/ 25% of the LEDs lite up and 15 hours at low brightness w/ 25% of the LEDs lite up so 10 hours is a happy medium.

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