Failed attempt at the $60 DIY Flex Light

When I saw the video on how to make a flex panel it looked so easy but I knew it wasnt and decided to not attempt it. I would have failed miserably.
 
Slavik, did someone pay you to post that? :smile:

The only be even slightly tricky part of that build is the soldering. The rest of it is cutting and sticking. I hate to be harsh, here, but if you really can't figure out how to cut some LED tape into lengths (any length will work, if you only cut where indicated) and stick it onto some fabric, I'm going to have to confiscate your tool-using ape card.

Soldering basics for anyone who cares:

Soldering led strip is harder than soldering, say, wires. It is not hard per se. The trick is to precoat the components (the wire end, the copper pad on the tape) separately, reducing the number of things you have to handle at once. This process is called tinning, at least in the UK.

Wet the soldering iron with a tiny dab of solder, less than a drop, for better conductivity. Bring the iron in contact with the work. Touch the solder onto the work. If it melts, the work is hot enough. Feed a very small amount of solder onto the work, until it is coated. The whole enterprise should take less than five seconds for small parts, though the LED tape is large (long) enough to sink away a fair bit of heat. The key is that the work must melt the solder, not the iron. If you just dump molten solder onto a cold bit of metal, it won't stick.

Once you've done this to both the wire and the pad, it becomes hugely easier to bring them together, apply heat with the iron, and feed in a tiny bit of solder to flow them together.

To avoid driving yourself blind, connect the positives using the pads at one set of cut points, and the negatives at another. It doesn't matter. All the positives and negatives are joined together.

For rigid panels, consider using a single piece of copper wire, like the inners of a network cable, laid flat against the panel. Put little squares of insulating tape over all the positive pads in a column, solder the piece of wire to each negative. Repeat for the opposite polarity, et voilà: quick and easy LED strip commoning. This would not work well for a for a flexible panel as the solid core wire would eventually fracture from bending, though you might be able to improvise something similar with stranded wire.

I think in any event, the likeliest failure point in that design (as so often) will be the wiring. Done well, the solder won't fall off. It's a very tough joint. What tends to happen is that the copper in the wire hardens from the heat of soldering, and becomes brittle, so the wire ends up snapping off the joint. That said, I suspect it would be reliable enough to use.

The bigger problem is that if you stick LED strip side by side like that without heatsinking, it gets very hot, possibly enough to noticeably shorten its life. Yes, this affects commercial products too.

Cheap enough to treat as semi-disposable, though.
 
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I saw that video six months ago and was going to try it too. I can solder. But then I too thought of the longer term reliability and asked myself if I would trust using this on a job for a paying client and the answer was no. Then I weighed just doing it for fun to see if I could do it (I think I could) but it seemed like a lot of parts acqusition and time for just a hobby thing and I already have too many other hobbies. I ended up buying two of the Aputure Lightstorm LS 1S and have been pretty happy with them overall. They are not perfect, a little green (easy to CC out) but the output on them is amazing and I love the wireless feature, it's so handy. I still like the idea of these flexible panels and will probably try some of the lower cost ones to buy but I talked myself out of trying to fabricate my own.
 
Thanks for the detailed instructions, Phil! I might attempt it again in a few months, and will follow your tinning instructions word for word.

And I wish we could get paid to attempt DIY electronics projects! But sadly it ended up costing us around $500 in parts to give this a shot. Still, the website is new and we need content so gotta feed the beast!

Cheers,
Slavik

Phil Rhodes said:
Slavik, did someone pay you to post that? :smile:

The only be even slightly tricky part of that build is the soldering. The rest of it is cutting and sticking. I hate to be harsh, here, but if you really can't figure out how to cut some LED tape into lengths (any length will work, if you only cut where indicated) and stick it onto some fabric, I'm going to have to confiscate your tool-using ape card.

Soldering basics for anyone who cares:

Soldering led strip is harder than soldering, say, wires. It is not hard per se. The trick is to precoat the components (the wire end, the copper pad on the tape) separately, reducing the number of things you have to handle at once. This process is called tinning, at least in the UK.

Wet the soldering iron with a tiny dab of solder, less than a drop, for better conductivity. Bring the iron in contact with the work. Touch the solder onto the work. If it melts, the work is hot enough. Feed a very small amount of solder onto the work, until it is coated. The whole enterprise should take less than five seconds for small parts, though the LED tape is large (long) enough to sink away a fair bit of heat. The key is that the work must melt the solder, not the iron. If you just dump molten solder onto a cold bit of metal, it won't stick.

Once you've done this to both the wire and the pad, it becomes hugely easier to bring them together, apply heat with the iron, and feed in a tiny bit of solder to flow them together.

To avoid driving yourself blind, connect the positives using the pads at one set of cut points, and the negatives at another. It doesn't matter. All the positives and negatives are joined together.

For rigid panels, consider using a single piece of copper wire, like the inners of a network cable, laid flat against the panel. Put little squares of insulating tape over all the positive pads in a column, solder the piece of wire to each negative. Repeat for the opposite polarity, et voilà: quick and easy LED strip commoning. This would not work well for a for a flexible panel as the solid core wire would eventually fracture from bending, though you might be able to improvise something similar with stranded wire.

I think in any event, the likeliest failure point in that design (as so often) will be the wiring. Done well, the solder won't fall off. It's a very tough joint. What tends to happen is that the copper in the wire hardens from the heat of soldering, and becomes brittle, so the wire ends up snapping off the joint. That said, I suspect it would be reliable enough to use.

The bigger problem is that if you stick LED strip side by side like that without heatsinking, it gets very hot, possibly enough to noticeably shorten its life. Yes, this affects commercial products too.

Cheap enough to treat as semi-disposable, though.
Click to expand...
 
Phil Rhodes said:
So glad you took that in good humour!

I could shoot a soldering demo, perhaps. Might be of generally interest.
Click to expand...

Seriously? That would be spectacular. Would be specifically interesting for anyone soldering LED strips, since like you said, soldering the pads are slightly different than soldering wires together.
 
I recently purchases my first car - a classic from 1973. Even though the car was in superb condition it did need some things fixed here and there. Enter the Internet and its wast army of idiots who benefit from the dream of DIY generation's desire to, well, do it themselves. The Internet is drowning with morons showing how easy it is to fix/do stuff. The videos are often cut for time thus skipping over the enormous amount of time DIY stuff takes and gallantly glance over the amount of specialty tooling needed.

That said, i put part of the blame on us, the viewers, who consume this nonsense. Instead of using common sense we get so easily charmed by the ease of the work all those videos proclaim.
 
Willing to bet part of your soldering problem was the solder, was it decent stuff from an electronics store with activated rosin (flux)? Lead or lead-free?
 
Phil Rhodes wrote:

To avoid driving yourself blind, connect the positives using the pads at one set of cut points, and the negatives at another. It doesn't matter. All the positives and negatives are joined together.

I'm slow and perhaps dyslexic...I can't envision how this goes! Could you walk me through that part again?
 
At each cut point there are two copper pads (or more, on RGB strip etc). All the copper pads marked "+" are connected directly together. All the copper pads marked "-" are connected directly together. So, to power up a bunch of rows, you don't have to connect all the adjacent pluses and minuses. You can do the + and one end, and the - at the other, or use adjacent sets of pads for the + and -, or whatever takes your fancy.

As to solder types, well, the modern lead-free stuff is not as easy to use, but it's not that bad.

P
 
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Lead free is bad for beginners and those without the tools that can really get hot enough and have the correct plating on the tip to handle it. But I'm betting the rosin in the little roll of solder is the real problem, looks like the cheap junk that I find at Lowes and Homedepot... Better than nothing in an emergency, but not by much.

For a job like this, I might use a flux pen to add a good grade flux to each pad before attempting to solder. An added expense but might yield easier results.

This is an interesting DIY, but wish the CRI was higher. I may need to check into this a little deeper and see what I can find, would make good rigid panels too. I'd probably go with a single daylight color mix and just dim all of them at once, gel for indoor colors.
 
Phil Rhodes said:
At each cut point there are two copper pads (or more, on RGB strip etc). All the copper pads marked "+" are connected directly together. All the copper pads marked "-" are connected directly together. So, to power up a bunch of rows, you don't have to connect all the adjacent pluses and minuses. You can do the + and one end, and the - at the other, or use adjacent sets of pads for the + and -, or whatever takes your fancy.

As to solder types, well, the modern lead-free stuff is not as easy to use, but it's not that bad.


P
Click to expand...

I had assumed (probably my first error) that the only way to power a 3 ft strip for example was to use the plus and minus pads at one end...you are saying I can power the plus at one end and complete the circuit using just the minus at the other end. I did not know that. Thanks for bearing with me!
 
I built it. I never soldered before, took have a day lessons on Youtube and got it to work. I built a larger panel, about 60x45cm.
Although it does work, I used thicker wire, which is not that flexible, so I highly doubt all soldering dots will stay intact when using this thing on set. So I won't.

The color on it, when using the strips the guy recommends in his video, is not bad but also not good anyway, has a noticeable green/yellow spike.

Meanwhile there are flexible LED panels ready to buy that aren't that much more expensive but are definitely more rigid and offer more features.

Well, at least I finally soldered something in my life.
 
I guess I come from a different era, and a time when schools had money. One of the classes I took when I was in High School was Automotive Electric where we learned all about the electrical systems of cars and such, how to trouble shoot, and how to repair. As a class project I built a volt/ohm & dwell/tach meter. One of the first things they taught us was how to solder.
 
Working on cars and in a machine shop is too dangerous for most schools now... Might lose a digit in a machine.
 
A kind neighbor, who is an engineer with some soldering experience, has offered to take a stab at breathing life into this project. I'm looking forward to watching how an expert gets it done! Thanks for the help everybody.
 
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