LED shoe
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LED shoe

by liamfahydesign on Thu Dec 06, 2012 5:25 pm

Hello,
I am making a pair of ladies footwear for banned and Paris Fashion Week that will have approx x130 5mm LED lights on each shoe flashing in a simple pattern.

Could you please advise me

- if a single x1 3v battery would be enought to power one of the pieces, or would I need 2x3v batteries? (can I use x2 anyway)
- best type of wire to use to wire it all up
- what type of microprosessor / chip / Device to buy to program the lights into a flashing pattern.

the circuit will be hidden underneath the leather, so its probably not necessary for conductible thread.

Much appreciated and please excuse any obvious questions, I'm clueless with electronics.
kind regards
Liam
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Re: LED shoe

by adafruit_support_bill on Fri Dec 07, 2012 9:23 am

if a single x1 3v battery would be enought to power one of the pieces, or would I need 2x3v batteries? (can I use x2 anyway)

Which 3v battery are you considering? Button or coin cells do not have the ability to drive that many leds. Something like a CR123 might work. Also, how much runtime do you need?

- what type of microprosessor / chip / Device to buy to program the lights into a flashing pattern.

What kinds of patterns do you have in mind? Does each led need to be driven independently, or can they be controlled in groups? Are all the leds single-color, or do you need RGB? It would not be easy to find a microcontroller with 130 IO pins, let alone 390. You may need to look at addressable leds.
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Re: LED shoe

by liamfahydesign on Sat Dec 08, 2012 11:02 am

Thank you

The battery should be as small as possible to fit inside the shoe so ideally a c2032 with a switch. We would need it to run for approx 8-10 Hours
The flashing pattern will not be individual LEDS but 9 horizontal rows of 11-14 Leds in some sort of sequence. All leds in single colour.

Kind regards
Liam
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Re: LED shoe

by adafruit_support_bill on Sat Dec 08, 2012 11:54 am

Button or coin cells like the 2032 do not have enough current to drive that many leds and certainly not enough capacity for 8-10 hours. A CR123 might last that long if you don't want to drive them at full intensity. A small flat LiPo cell such as the ones used in cell-phones might be easier to embed in a shoe. Driving 9 rows should not be a problem. Something like an Atmega328P would have enough pins. You could prototype the circuit with an Arduino, then miniaturize it to fit.
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Re: LED shoe

by liamfahydesign on Sat Dec 08, 2012 1:30 pm

Thank you very much, this is extremely helpful.

If you dont mind could you please give me the links to the individual products on the adafruit site (Atmega328P and a device I can program it with, a suggested battery etc) so that i can purchase them.

And could you suggest any specific type of LED's (5mm cool white) to accomodate a low voltage?

regards
Liam
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Re: LED shoe

by adafruit_support_bill on Sat Dec 08, 2012 2:51 pm

We have the 328Ps in the store. https://www.adafruit.com/products/123
You can program it in an Arduino, then remove the chip to put in your own circuit. https://www.adafruit.com/products/50

The 328P will need some support circuitry. If you are new to microprocessors, it might be better to go with something like the Arduino Micro: http://www.adafruit.com/products/1086
This has all the essential circuitry on-board and you can plug this directly into your computer for programming. We do expect to have a 'headerless' version sometime soon that would be even more compact.
There is also the "Teensy": https://www.adafruit.com/products/199 which is a very compact solution as well. Not quite as beginner friendly as the Micro, but easier than working with bare chips.

Both these boards are designed to run on 5v. That would require 2 cells and a voltage regulator. I suspect they might be able to run on a single 3.2v cell (the Arduino UNO does), but I have not tested this.

We have both 3mm and 5mm white leds.
https://www.adafruit.com/products/778
https://www.adafruit.com/products/754

You will also need 9 transistors for switching the rows of LEDs. These should do the job: https://www.adafruit.com/products/756.
We do have these https://www.adafruit.com/products/970 which pack 8 transistors into a small package. 2 of these may be more compact than 9 discrete transistors.
You will need some 1K resistors between the processor and the transistors (sorry, we do not carry these).

The smallest LiPo cell we have is this one: https://www.adafruit.com/products/258
There are smaller ones out there.
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Re: LED shoe

by liamfahydesign on Tue Dec 11, 2012 2:37 pm

Thank you very much, thats immensely helpful!
I will get cracking putting it all together

regards
Liam
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