Inverter redo
January 25, 2010 4:40 PM   Subscribe

Can this circuit board be redesigned? If so, how can I find someone to do it? (also inverter, battery question)

I have this circuit board/inverter/battery pack. I need to reconfigure it to fit into a 1/2" by 4"-6" (length approximate and flexible) for an el-wire art project.

Photo here

1) Can it be done? For example, can someone rewrite the circuit board so it has a 1/2" x 2" layout instead of 1"x1"? Is it configurable so the parts can be laid out length-wise?

2) Who does this kind of stuff? I would like to send it somewhere and have them reconfigure the whole thing, but as an artist, have no idea how to find someone and how much it would cost.

I know nothing about this and would prefer not to have to learn it. I just want to give it to someone, have them do it for me, and, if this project works, a way to have more made.

( I found this site: Pad to Pad and they could do the circuit board for me (great, I want to eventually have them/someone to manufacture them for me), but I have to send them a schematic on their software. And it is for the circuit board only)
posted by Vaike to Technology (17 answers total)
 
You could hire an EE student to make such a thing maybe, but just printing the PCBs would be expensive (easily $30 per one-square-inch board). This site has a variety of inverters, including some that look just like yours and some that are much smaller and sell for under $5.
posted by miyabo at 5:00 PM on January 25, 2010


Short version: No, not in the way you're thinking.

You don't mention what you need this for. If it's for some kind of power, there's probably a very simple circuit that will suffice and fit within your size constraints. Even if you create a new circuit (difficult unless you're an advanced hobbyist or engineer) or take the design from the one you have, you bump up against the problem of making a new circuit board, which is Not Cheap in small quantities.

Your best bet is probably to find something else that fits what you need. If it's for something straightforward, there's probably a cheap Chinese widget available or even a hobbyist on the Web somewhere selling a kit for it (and after that it's just soldering).
posted by neckro23 at 5:03 PM on January 25, 2010


EL inverters come in all shapes and sizes. It would be cheaper and probably quicker to just buy one that matches your dimensions and wire requirements.

Failing that, I'd give it and some $$$ to a high school electronics enthusiast - they might be able to saw the board in half and bridge the cut connections with wire, but some of the traces in EL applications are sensitive to capacitance, plus (s)he might screw up, so the result might be a busted inverter and refund.
posted by -harlequin- at 5:05 PM on January 25, 2010


1) Of course! You can either layout the exact same circuit in a PC board that fits your specifications, or design a new circuit board with similar functionality.

2) Electrical engineers. You want to find a consultant. I'd expect you will pay $500-$1000 for a board of that complexity. Maybe less overseas... I've ordered PCBs from www.seeedstudio.com before, and remember that they had a prototyping/consulting service, but I don't have any experience with it.
posted by lalas at 5:05 PM on January 25, 2010


Taking someone else's circuit and repackaging it is a violation of copyright.
posted by Chocolate Pickle at 5:17 PM on January 25, 2010


miyabo: I have been searching online for days, they are still to large in width but thank you.

neckro23: I need it to power about 15 feet of el wire. I ideally want the wire to have the three speeds that all el wire I have seen usually have: on, rapid blinking, slow blinking.

-harlequin-: I would love to buy one if I could, but can't find one for the life of me that is 1/2" wide or less. But I don't mind trying and failing, so the student might be a good idea.

lalas: Thank you for answering question one. I don't want to pay quite that much, but I am willing to pay around $200 ish for one. Knowing it can even be done is so helpful.

Chocolate Pickle: Whew! Glad I know that. But I can have someone start from scratch and build me one that does almost the same thing (on, slow blink, long blink), yes?

Thanks for the answers. If anyone has more, it would be very appreciated.
posted by Vaike at 5:37 PM on January 25, 2010


Taking someone else's circuit and repackaging it is a violation of copyright.

No I don't believe so. This is classic reverse engineering. Perhaps the original layout could be copyrighted, but that is explicitly what your recreating from scratch - a new original instantiation of the schematic in a pcb form.

Its also very unlikely that the original schematic circuit has any IP protection because there is tons of prior art on a circuit like that.

Think of this like two people painting a picture of the same landmark - neither can claim copyright over the other's work and the landmark is of course public domain.
posted by Long Way To Go at 5:45 PM on January 25, 2010


For $200 including parts you're looking at an enthusiastic high school or college student building it on perfboard. You start getting into trouble when you start saying "I want it to do this plus these other normal things that boards like this do" -- if the existing board doesn't already do those things, it's possible the reverse engineering will be so hard as to make it "easier" to just build another from scratch. The picture is a little fuzzy but that board looks pretty tightly packed, so you may run into trouble cutting it in half and bridging all the connections you severed. On the other hand, I'd be really surprised if the capacitance problems harlequin mentioned were actually any trouble.

More importantly: How much time to you have? Printing a circuit board with 3-day turnaround time is about $150, and that's after you get it laid out. Even a good student EE is going to need a fair amount of time to do the work you describe. Forgive me if I'm jumping to conclusions but I'm getting the sense that you think this might be really fast & easy if only you could find the right person -- that may well be true, but not until you hit about 10x your proposed budget.

Also, I hate to feed the AskMe tendency to question the assumptions of the asker, but at some point you're going to need to re-evaluate how much time and energy you're actually willing to put in to save yourself half an inch of width, versus devising an artistic (ie, within your competency) way of working around it.
posted by range at 7:00 PM on January 25, 2010


Any chance you could deal with the wire in two sections?

tiny, cheap inverter
posted by ecurtz at 7:07 PM on January 25, 2010


Thanks. The whole project, which I would love to eventually turn into a prototype, can only be just over 3/4" in diameter, so that is really my only constraint, the width, but that is mandatory. I can also start, if I have to, with the el wire just turning on and off, nothing else, so I would imagine that would help making it smaller (?).

I am just at the point where I am not able to put a lot of money into it until I know this is something that would work, and would eventually sell. So, yes, ideally I would like to get on put together, even if it is a hack job, just to see if this all works and is fabulous and people like it. If so, then I am fine with putting more $ into it. If I can get what I am looking for I could stretch my budget, but I am still figuring out if it is possible, as I know nothing about this kind of stuff at all.

So a student might be perfect.

Also, as I am failing with the el wire inverters online, could I possibly use something else? Would it just need to have the same power output? Any terms to search for would be wonderful, as that might solve my problem.
posted by Vaike at 7:18 PM on January 25, 2010


ecurtz: yes, I could. But the 9v battery is too wide. Is there a workaround that way? Could I use two AA batteries?
posted by Vaike at 7:20 PM on January 25, 2010


You can't use something to substitute for an EL inverter. EL materials require low voltage, high frequency AC which isn't used for much else.

You absolutely could use an inverter intended for a 9v supply with 4 standard 1.5v batteries. AA/AAA batteries are 1.5v and less than 3/4ths of an inch wide. Some watch/hearing aid batteries are 1.5v too, but they'd run out of juice really fast.
posted by miyabo at 7:52 PM on January 25, 2010


By "4 standard 1.5v batteries" I mean "6 standard 1.5v batteries." 6*1.5=9, and DC voltages add up if they're in series.

If you can squeeze those into your application, it's probably your best bet.

Also maybe look into lithium ion batteries... there are some standard sizes available online, they're rechargeable, and they hold a lot more juice for their size.
posted by miyabo at 8:00 PM on January 25, 2010


Thank you everyone! I am combining ecurtz and miyabo's suggestions for a perfect 'hack' which will allow me to get this project going.

But, if all goes as planned, I will still be looking for a reworking of the circuit board and inverter, so if you have any other ideas for that (with less of a worry of budget), please do let me know.

Yay! I can go get back in action and stop googling now. My appreciation of this community is so very great.
posted by Vaike at 8:19 PM on January 25, 2010


No I don't believe so. This is classic reverse engineering. Perhaps the original layout could be copyrighted, but that is explicitly what your recreating from scratch - a new original instantiation of the schematic in a pcb form.

Its also very unlikely that the original schematic circuit has any IP protection because there is tons of prior art on a circuit like that.


"Prior Art" is relevant for patents. It has nothing to do with copyright.

The question is just how much engineering is involved in your reverse engineering. Creating a new circuit from scratch which performs the same function, without making any attempt to find out the details of how the old one works, is not a violation of copyright. (It could be a violation of patent if there were a patent covering it, but it's highly unlikely there is one for a circuit that simple.)

If you take the old circuit, figure out the wiring, reproduce the original schematic, and then lay out a new board from that schematic, you're violating copyright.

Whether anyone would find out and sue you, of course, is an open question.
posted by Chocolate Pickle at 11:16 PM on January 25, 2010


"Prior Art" is relevant for patents. It has nothing to do with copyright

Yes, that's why LWTG mentioned prior art. Copyright protects an expression, not an idea, especially not a purely functional idea. Re-implementing the same circuit with your own PCB layout should be a new, non-copyright-infringing work, leaving patents as the only likely IP infringement. Of course you might get sued anyway.

Anyway. Back to the original question. I've used some of the tiny inverters from coolight; they seem like they're small enough to do the job, but the ones I've used don't have a blinking pattern. Building just a circuit to blink a separate inverter on and off would be a bit simpler. You're still unlikely to get it below $10-$15 apiece until you start making hundreds or thousands of them. (Plus a sizable upfront engineering cost, which is mostly labor.)

Do you know anyone in the Burning Man community? If so they might be able to put you in touch with someone with extensive knowledge of the inverters that are commercially available.
posted by hattifattener at 1:23 AM on January 26, 2010


ecurtz: yes, I could. But the 9v battery is too wide. Is there a workaround that way? Could I use two AA batteries?

The inverter ecurtz linked to runs on 2xAA (3V). It uses a 9V-style attachment but tells you in the title to not actually use a 9V battery.
posted by 6550 at 4:13 AM on January 26, 2010


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