EL panels / tape: cutting and rewiring?

EL Wire/Tape/Panels, LEDs, pixels and strips, LCDs and TFTs, etc products from Adafruit

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Emor
 
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EL panels / tape: cutting and rewiring?

Post by Emor »

I have a very small application where I'm going to be testing EL to replace a few small LEDs, in order to hopefully achieve more even light distribution. I'm ordering Adafruit's coin cell inverter.

The area to be illuminated is a 2"-diameter circle, at most. Adafruit's smallest 10cm-square EL panel could make four of the necessary units, and I understand the panel can be cut. But can each segment be re-soldered, or is the existing connection the absolute only way to hook the panel up?
Another question: if a 10X10cm panel is cut to a 5X5cm panel, will it only draw 1/4 the current as the larger panel? That is, will the smaller panel quadruple battery life by comparison to the larger?

I'd also like to test the EL tape, and I understand the tape has connections at each end making it possible to get two pieces per order. But once again the question is whether I can cut the tape more than once, is there absolutely no possible way to solder up new connections to a piece cut from the middle?

The EL wire may be another possibility, since it can be cut into small segments and soldered up as needed. In that case, I would want to coil the wire in a tight spiral fashion to make a flat 2" disc shape. Can anyone advise me on how flexible the wire is, and whether it would handle this kind of treatment?

Thanks in advance for any and all tips!
Last edited by Emor on Mon Jul 27, 2015 4:07 pm, edited 1 time in total.

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adafruit_support_bill
 
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Re: EL panels / tape: cutting and rewiring?

Post by adafruit_support_bill »

We have not had any success attaching leads to the tape or panel sections. That is why we have the manufacturer terminate the tapes at both ends. The wire can be bent in a relatively tight radius. But repeated flexing of that sort will cause breakage of the corona wires, so plan on doing it just once - and maybe order a bit extra just in case.

The current draw is not a strictly linear function of surface area. Since the inverter is essentialy a high-voltage boost converter, there is some efficiency loss in the inverter itself. For small sections, there is probably more loss in the inverter than in the wire or panel.

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Emor
 
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Re: EL panels / tape: cutting and rewiring?

Post by Emor »

adafruit_support_bill wrote:The current draw is not a strictly linear function of surface area. Since the inverter is essentialy a high-voltage boost converter, there is some efficiency loss in the inverter itself. For small sections, there is probably more loss in the inverter than in the wire or panel.
Thanks for the reply, Bill. Makes perfect sense.
I am of course disappointed to learn that the panel and tape materials cannot be cut and rewired.

I've ordered the inverter, and samples of the panel, tape and wire materials for testing.
Part of that testing will be to determine whether I can come up with some workaround for cutting and soldering the tape and panel materials.
Will let you know if I have any success!

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Emor
 
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Re: EL panels / tape: cutting and rewiring?

Post by Emor »

After testing the EL wire, tape and panel when powered from the CR2032 inverter, here's what I found:

- the EL wire, when cut to an 18" length and coiled into a tight spiral (about 1.5" diam), will illuminate but could not be considered bright. An awkward solution for my need in any case, and would add about 2.4mm to the thickness of my design. Ruled out.

- the EL tape turned out to be far to stiff to consider folding it to cover the 1.75" circle I need to illuminate. Ruled out.

- the EL panel material, once cut down to an irregular circle <1.75", illuminates very nicely - for a while. Within an hour, the battery is drained to the point that brightness is reduced by about half...but the thing will at least remain illuminated for several hours before depleting the battery entirely, which is better than I had expected overall.
So I now have a (moderately) successful solution!

Now, if only Adafruit would sell 3.3cmX3.3cm EL panels, as Bill mentioned he'd suggest to The Adafruit Powers That Be....

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semegraph
 
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Re: EL panels / tape: cutting and rewiring?

Post by semegraph »

For anyone who happens upon this forum searching the internet, I have had luck attaching new wires to "scrap pieces" of EL panel, I have reproduced this success 3 times so far. Note when you look at the panel there is a thin "track" that runs around the edge of the panel, it is separated from the main square of EL ink in the middle of the panel. The thin track is like the corona wire on an EL wire. When you cut your scrap to shape, leave a little tab, maybe 1/4" x 1/4" off your scrap that includes some of this track and some of the main glowing surface. Split the layers of plastic laminate on the end of your tab with a boxcutter, try flipping it back and forth over the edge like a guitar pick to get the layers apart at the end. Once you have them separated at the end, peel them apart carefully along your tab, only peel apart the tab part, not the whole panel! Using the boxcutter, scratch a few scores into the material that is exposed, on the track side and on the glowing surface, so that the conducting surface is exposed along these scratches. Dab some Bare conductive paint on the tips of two small wires, I used JST connector pigtails, and ring a little superglue further down the wire right against the insulation, and place them between the plastic layers right where you scratched through the EL material, be careful not to put them too close together or the bare paint will short across them when you squeeze the layers back together. Squeeze the layers tightly with needle nose pliers until the paint dries, even while it is wet you should be able to test the connection with an inverter to see if your connection is good. It might help to cut a small triangle in the margin between the "track" and the glowing surface to help avoid shorts. Reinforce the connection by wrapping with some black electrical tape. Hope this helps someone!
Last edited by semegraph on Tue May 31, 2016 1:57 pm, edited 1 time in total.

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adafruit_support_bill
 
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Re: EL panels / tape: cutting and rewiring?

Post by adafruit_support_bill »

@semegraph - Thanks for posting your technique. I'm sure that some will find it helpful.

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semegraph
 
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Re: EL panels / tape: cutting and rewiring?

Post by semegraph »

I actually made a video of the process today, since I have done this quite a few times now and feel pretty confident that others ought to be able to do it as well.

https://www.youtube.com/watch?v=ghSii8GO7GY

I recommend the first attempt use a scrap piece of EL panel to make mistakes with.

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bloseclan
 
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Re: EL panels / tape: cutting and rewiring?

Post by bloseclan »

The EL tape is 1 cm/10 mm wide. Can this be trimmed to a o.5 cm/5 mm width and still work?

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adafruit_support_bill
 
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Re: EL panels / tape: cutting and rewiring?

Post by adafruit_support_bill »

No. The positive and negative power buses run up the edges of the tape. So if you trim them off, it will not light.

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semegraph
 
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Re: EL panels / tape: cutting and rewiring?

Post by semegraph »

How long of a 5mm strip do you need? It's possible you could trim a peice of EL panel to that size if you are careful to preserve the bus bar at the edge, but you'd only get a few inches of length.

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Re: EL panels / tape: cutting and rewiring?

Post by bloseclan »

I am looking at the panels now. Need about 11cm, most fairly inexpensive panels are, of course, 10 x 10 LOL

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Re: EL panels / tape: cutting and rewiring?

Post by adafruit_support_bill »

If it doesn't need to be totally flat, another option would be a 5mm side-light fiber optic tube: https://www.adafruit.com/product/4164

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