[Noisebridge-discuss] Connecting 128 EL-Wires to an Arduino

[Sean Cusack]

If you have any kind of space constraint or form factor considerations, I'd
highly recommend using fewer, bigger inverters. I've made a costume that
contains 70 feet of EL wire, and I drive it using 2 cool neon fish
inverters<http://shopping.netsuite.com/s.nl/c.ACCT88394/it.A/id.194/.f>*caution:
works on 9-12V DC, not 5V!*. I used to use 3, but ended up bailing
for the following reasons:

1) I couldn't route the wire to connect them all in parallel since it would
have wrapped all around my body and tied me up. Therefore, I had to carry
around 24 AA's in order for it to work.

2) The problem when you start adding more and more batteries is that you can
never be sure if they are all at the same charge level. In other words,
trying to get any kind of consistent brightness across strands is pretty
much impossible.

3) Each driver puts off some noise. In a loud atmosphere, you'll never hear
a few of them, but if you end up using a bunch...like 20, its probably going
to start sounding like a deadly mosquito attack. Also, every driver gets
hot. Since I carry these right next to my crotch...I started to...well...get
uncomfortable (with 3 of them).

Also, remember that EL wire brightness is derived from frequency*volts.
Since you're sort of stuck on a pretty narrow range of frequency, you're
going to have to bank on voltage. With only a 5V supply, you're stuff is
only going to work in pitch black environments, or you'll be changing out
batts every couple hours or so.

Lastly, unless you want to do something really crazy, why not let someone
else handle a section of the sequencing for you? You can probably get a fair
amount of the way there by using this off-the-shelf sequencer, and then
hacking it to go the rest of the way:
http://shopping.netsuite.com/s.nl/c.ACCT88394/it.A/id.192/.f

Hope it helps -
Sean

On Tue, Jul 20, 2010 at 12:28 AM, Gregg Tavares <nbridge at greggman.com>wrote:

> Hello Noisebrige,
>
> My name is Gregg Tavares. I'm new to the list. I hope can contribute more
> than I take.
>
> I'm mostly a software engineer, not hardware so I'm looking for advice.
>
> I'm planning to build a el-wire display with 128 individually addressable
> el-wires.  (yea, I know it's a ton of work)
>
> My current plan is an Arduino connected to 8 MCP23018 16-bit I/O expander
> chips<http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en537375>connected in series with
> 2 of these El Escudo boards
> <http://www.sparkfun.com/commerce/product_info.php?products_id=9259>on
> each of those along with these ifw-3294 power inverters<http://www.coolight.com/product-p/ifw-3294.htm>
>
> It seems fairly straight forward. I'll take it a step at a time. If can get
> 1 MCP23018 working with 2 El Escudo boards and 16 el-wires then it should be
> pretty easy to chain in more of that combination to expand the number of
> wires.
>
> The question I was hoping to ask is is there a better way? Should be
> looking at different solutions? One big power inverter to power all the
> el-wires? Some chip I'm unaware of that handle's more outputs?
>
> I'm grateful for any insight or advice you might have.
>
> thank you
>
> -gregg tavares
>
>
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>
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