Hey everyone. I have been getting rather frustrated with a small lighting project over the last few days. I have successfully used those single 5050 ws2812b modules in the past, and when trying to get a new brick of 100 going, I am getting shorts constantly to where the arduino won’t even power on. I consider myself a decent soldering technician, so I have checked my joints. Right now I’m starting to question the batch of leds I received. I have made several 6 module strips like this and about half have actually worked. I even went backwards unsoldering the first three and they worked. Then the second I added the fourth, the arduino wouldn’t start. Has anyone ever experienced and dodgy modules in the past?
There is one thing I see. I slightly walked a few pads over on the PCB using solder. There actually are very small holes in the silk screening that I suppose could bring hot solder down to a different layer of the PCB. In turn short everything…
With the simplicity of the WS series, I would hope there’s only 2 layers, and furthermore, that there’s no vias that would inadvertently short another layer. there should be a layer of dielectric between the silk screen and any copper too…
Have you checked the consistency of the connections of the individual LEDs?
Also, have you checked everything with a meter and what happens when you power/test the segments that you removed to make it work?
I played with these modules a while back and I kinda soldered them like you did. I actually got the exact opposite effect with them, they were not shorted but had strange ‘open circuit’ style problems.
Have a look here… https://plus.google.com/106626345342202981932/posts/TqWBtiHJHjX
I am not 100% sure but I concluded that those little PCBs were flaky and did not react well to any overheating due to soldering.
I also consider myself reasonably good at electronics soldering but still managed to get quite a few bad pixels soldering them that way.
Wow. Thanks JP. This is a clear case of purchased crap! Might as well flush them… That thread clearly states problems and I think I will need to rethink my rear warp nacell on my mini quad.
If you are having heat issues, I would use a long wire, solder on what you need… cut off the excess. keeping all the extra wire attached will act as a heat sink… worth a try. Also I don’t think you need to solder each side of the power traces since they should be common… just solder to one on each pixel.
I have a couple trial packs of these. figured they were only good for singular, dispersed usage anyway… seems like if only the designers would have created jumper traces for continuity, they would be great to use…
I do like that they snap right off in single pixels though.
Ditto to the posts suggesting heat sensitivity ( @JP_Roy @Synthetech @Jeremy_Spencer ). I’ve had similar experience with these. Still, love them when the circumstances are right and always get high quality ones (if there is such a thing).
I’ve not used the product, but I have a considerable amount of fine pitch and sensitive product soldering experience. I would say that the heat issue that many have brought up is likely a possible culprit, and having some form of heat sink on the sensitive component during soldering would be a good idea. Also, it appears that you are using a lot of solder at each pad. I would say that anything that protrudes above the lead you are soldering is too much, perhaps reducing the solder load on your iron would help. It also appears that you are using flux before soldering, and I commend you for that, but the solder bulbs indicate that the flux might not be working effectively (the flux should wick the solder beneath the wire or component lead and not leave a solder bulb, assuming that you don’t apply too much solder. The flux should also act to reduce the amount of time necessary to apply the solder, preventing overheating components), and also, from the image, it looks like you have not cleaned the flux off. In my early days of soldering I used a dropper bottle of flux and when I did not clean off the flux effectively, I experienced shorts due to the flux, so that could be an issue as well.
another poster suggested that you need not solder between power pads, and I would say that is correct. Skipping that extra connecting wire will reduce the time the components are heated. In keeping with heat reduction, also allow the PCB to cool between soldering connections. Trying to work quickly will raise the temperature felt by the components even if you solder each pad for an appropriate time since the PCB will retain heat from the previously soldered pad, and then increase it’s heat from there.
I’d hate to think that you have to throw out a batch of components without cause, which is why I posted. Good luck.
It does also depend on the quality of the underlying product. I use lots of different sized rings as halos and other lights in cars. The rings with the black PCBs tend to be the worst quality, the ones I’ve had specially made seem to be better as are the ones with the grey PCBs. I always restrict the maximum brightness to about 230/255 which helps a lot.
