17mm & 20/26/27mm single-sided DD/FET driver release: A17DD-SO8 / A20DD-SO8 / etc

Generally when I’ve ripped pads off in the past (yeah, many times) it’s been because of misbehavior on my part. Ripping LED+/- pads off isn’t something I’ve done much of though. Generally I’ve damaged component pads due to lots of heat and pressure. Before I learned to add solder when removing components I frequently applied pressure to components while attempting to remove them. Between the extended heat dump from my efforts and the pressure it was common to damage a pad. I’ve also damaged SOIC pads after air-wiring directly to them and then manhandling the assembled PCB.

I don’t see it as a problem that needs to be solved, although I’ve been adding big vias when I had space and they didn’t seem to interfere badly with other things. Maybe I should re-evaluate? If it doesn’t have any downside I can see the advantage of a hole for wiring the LED directly to BAT+ or BAT- depending on the type of driver. These PCBs are small and if drilling is to be done it’s better/easier/nicer to let the fab do it IMO. People don’t have to use it, but for those who want to it’s already done… OTOH aesthetically I do not think that the large vias are beautiful and they do take up space that could be devoted to large SMD pads or other misc stuff.

I used to try to use 20 ga teflon insulated wire that is very stiff. Trying to stuff the driver in a tight space where the wiring has to be manipulated would pull the pad off the driver.

Now that I use 22ga Silicone insulated wire that never happens.

Oh, er, yeah. I’ve removed other pads by accident while un-soldering things. Probably for the exact same reasons. But those were generally pads I wasn’t planning on ever using again.

Through-holes are definitely sturdier, and preferred when possible. Attaching 3x22g wires (twisted and soldered together) to the LED+ and LED- contacts in my SRK wouldn’t have been very feasible without the through-holes on the BLF-SRK driver.

I asked Matt to put them on the Tiny10 for the sake of versatility and with so many doing spring mods having a single wire go from the top of the driver spring straight to led+ makes some sense(spring carries only mcu current) but yes, since I’ve switched to more flexible wire my pads are in less danger. 0:) Being able to solder the connection from a less crowded side can be nice too.

This is where I learned what via’s are for (or one of the things), were it not for the via’s, there would be no way to hook up power and emitter leads on this 10mm PICcolo. Heck of a first place to learn, huh?

I usually build one driver at a time, as I build the light. Once in a while a couple at once. This time I got some A17DD-S08 boards in that had 6 still together, in 3 “pages” along with a few loose boards. So I thought I’d try doing 12 at once and taking pics along the way, show y’all the video library my camera builds.

Now, my shoulder has been giving me fits for weeks. I’m on meds and kinda loopy. But if I can pull this off, even take pics, then I reckon almost anyone can build one of these single sided boards. No iron soldering involved here at all. And if I’d wanted to really make it easy I’d have put a dab of solder paste at the LED leads so when I go to put wires on these they’d be super easy. I left that out on purpose so the pads would show better. The MCU’s are all flashed, ready to go. So as I get a light to build it’ll be much quicker and easier to do. If it’s an e-switch design I can re-flash the MCU before I start, but the tedious work is all done. :slight_smile:

Love these single sided boards! :bigsmile:

You should team up with Rich.

That is some beautiful work Dale, i had planned to use a syringe to apply paste for the reflow but that stencil is just too convenient, how do i order one? and where? is it https://www.oshstencils.com/ because they seem to expect me to upload the design, do i just download the design of the ospark page and upload it to them?

If found this also CREE MTG/XRE/XML/XPG solder paste stencil from texaspyro
https://oshpark.com/shared_projects/dw8NYoED
this will really make things easier :slight_smile:

Which paste do you use?

If the plan is to just protect against solder pad rip-offs, wouldn’t a small via (in the middle of a solder pad) work just as well, because it will act as a rivet of sorts? But, pushing wires into the big vias and soldering there is certainly convenient.

I was also going to buy the stencil but had to have some sort of file to buy one, great work dale similar to what i did but using my vice and hot air station

I have not been able to get the stencil business to cooperate for me.

Do you mean that you don’t find it more convenient or that you haven’t been able to order one?

I only have a stencil for LEDs (TP’s stencil) and I always have a lot of trouble getting the paste to deposit properly. (Either not evenly, not at all, etc.) I don’t use a PCB jig, but I do use extra PCBs to level the stencil. Ordering the stencil is easy, just download the zip of Gerbers from the appropriate OSH Park listing and upload it to OSH Stencils. While the amount of solder paste deposited on any one pad is significantly less important with drivers than with LEDs, I still can’t imagine myself getting results like DBCstm showed.

Also the syringe is pretty easy to use and is flexible. I make a lot of layout changes, both minor and major. That would require a lot of stencils.

As I recall, you can upload the entire zip file and when ordering it will use the proper layers.

https://www.dropbox.com/s/njyq3ncg5zha6fw/17mm_A17DD-SO8_v024.zip?dl=0

And yes, texaspyros stencil for the emitters is immensely helpful, I use them a lot…need to get some new one’s as a matter of fact.

I had ordered 2 of these for the A17DD-S08 and that was good, because it allowed me to cut a left and a right to do the 6 board page. :slight_smile:

Edit: Sorry, I use Kester EP256 in a syringe. I find it has the best flow and is easier to appy. The Mechanic’s in the tub is thick and sticky, very difficult to use with a stencil.

Like your video, DBCstm! I never realized how easy surface mount could be.

For those of you sourcing parts from Digikey… did you know if you prepay your order with a check they will ship for free? I haven’t ordered from them in a while, but this is what the front of my old catalog from 2007 says, “When a check or money order accompanies your order, Digi-Key pays all shipping and insurance (our choice for method of shipping) to all addresses in the USA and Canada, unless such charges exceed 10% on orders of $200 or less, or 5% on orders greater than $200. Digi-Key will notify you prior to shipment if these conditions exist.”

I took advantage of this several times when I was selling a circuit board that I had designed. I never had them not ship due to the 10% or 5% exclusion.

Maybe somebody with a newer catalog can see if the policy is still in place? It was in the fine print under the heading “Ordering Information.”

I thought about taking full on video, but doing it all by myself it was easier to set up the camera and let the Video Library get short video clips at each picture and already have it all tied together. If I had a willing accomplice they could shoot video and do close-ups and such and I could tie all the clips together with Sony’s Vegas Movie Studio.

The actual pictures from the re-flow stage show more clearly the solder liquifying in stages when looked at full size. I didn’t get closer for macro style stuff because I didn’t want my camera part of the re-flow action. :wink:

Still ended up a pretty large video file, and even included the one fuzzy shot that didn’t focus due to the close-up lens. lol

Thanks wight, i understand now when you are developing these drivers using stencils is of less use with all the different revisions.

Dale now you got lots of drivers to last you a while but next time, could you film the process of applying the paste on the stencils and pressing it on the pcb, and the amount paste to apply to the led stencil would be interesting also, before wight just now mentioned it i didn’t know there was some optimum amount for that.

Edit,
I just saw your mention of Kester EP256 i almost missed it, ok you can use paste in a syringe for the stencil work also, i had only heard of the tub before, i guess Kester EP256 it is then everybody is talking so highly of it.

The thickness of the stencil is supposed to determine how much paste is deposited. When you wipe the paste over the stencil excess is taken away with your card/squeejee.

Ok i get it, Nice thats why every of those paste jobs Dale did looked so pristine, i thought it was some special move required :slight_smile:

In trying to do so many at a time I wasn’t completely successful in holding the stencil flat down on the board, a few of those had thicker deposits of solder paste than necessary… one so much so that a resistor floated over and joined it’s neighbor! Other than that though it went pretty well, I’d never attempted that before and think it’s cool to see it happen. :slight_smile:

That was really my point in sharing this, I’m not especially talented…if I can do this most anyone can! Give it a try! The pads are even large enough to do it with a soldering iron, it just doesn’t come out quite as neat. :wink: