Oshpark Projects

Cajampa asked me to draw up a switch PCB for the sole purpose of having the least resistance possible. This is the result.

  • 16.8mm OD
  • 10mm Spring pad
  • (15) 0.7mm vias per pad
  • Large 1.15mm via in the center for easy soldering of spring-bypass wire
  • 2mm holes on either side in case you still decide to do a total pcb-bypass
  • Outline on board is an Omten 1288

Hopefully this makes Cajampa as happy as the PCB appears to be :slight_smile:

Such high frequencies may not be a problem here, but for some circuits, interference is reduced by making more of the board copper, even where not needed for lower resistance. That is from the capacitance between the sides of the board. That also helps with heat flow. On the other, hand, narrow traces to the control unit might protect it with their resistance and possibly their inductance.

Thanks for the explanation Tom E, it is good to know.

Thanks, Yeh probably still working in it I have a version that uses 0603 parts and that’s fine

Yeah :slight_smile: thanks for doing this PD. Very nice to get pre done bypass holes also.

Feels great you having taken the higher amp capable switch board to the logical BLF end game. As we realized with Dale’s testing of the lighted version and his bypass of it, the gain is a possible little less than one % but if we don’t want lighted tailcaps in a build why not get a max amp one instead :slight_smile:

And love the grin design, it grins just as much as i will when i put it to good use knowing that perfectionist pleasure that the switch pcb is pushed as far as possible, in lowering resistance and minimizing that precious volt drop to the high Vf cree led we all like to use in our brightest builds :bigsmile:

Fritz t. Cat had an interesting point above here about lots of copper in the boards, i think it is likely that these higher amp switch boards should reduce switch failures by being better heatsinks for the switches also.

Updated post #1605 above with a note. Hope RMM can help clarify - think he might know some bout this.

I hope RBD updates the OP with these latest items.

Just a suggestion but the highest source current occurs at the fet so the most gnd vias should be there, next is the 7135 source, then the mcu, and lastly the voltage divider and OTC so the vias should be allocated accordingly. Most drivers seem to be designed with only led+ given high current capability forgetting that single sided drivers often need to get current to B- through the bottom of the pcb. Glad both you and Rich are paying attention to this.

I’ve caught up on adding links to the op. There are a number of projects out there on the forum that aren’t listed partly due to their prototype nature and also due to my reluctance to mine the forum for these things without their creators stated approval. If you’ve posted something and I’ve missed it or wish something to be added go ahead and list it here or feel free to wack me with a pm.

FYI for the OSHPark DIY folks

http://docs.oshpark.com/services/two-layer-hhdc/

2 Layer Half-Height Double-Copper

A special stackup intended for a variety of high-power and low weight circuit designs. This service features a 0.032” (0.8mm) thick PCB, and includes 2oz (2.8mil, 70um) copper. That’s half the thickness of our standard boards, and with twice the copper!

Thin board, thick copper…imagine the current J)

P.S. Pilotdog…been watching your shares on OSHPark…wowzer…you are off the chain on designing man…great job!

This is very good news!

Wow, that sounds great! Thanks for the advice!

P.S. +1

Thanks for the compliment!

Man this is sweet…… Same price as the original boards too! For drivers the thickness was fine, (but still an upgrade to the copper) but the half-thickness is fantastic for the tailcap boards. I’m ordering some right now!

Excellent! Oshpark just gets better and better! 0.8mm PCB, 2oz copper, same price! :party:

Even the reduced thickness for drivers could give some space where it’s crucial, I guess.

So when can we see a µC-LTC board from you PD :bigsmile: ? Please?

Nah, just kidding. What’s the LTC Board you’d go with right now? I’d like to give this a try too.

What do you mean, µC-LTC ?

A lighted tailcap controlled by a small MCU. Something like mashm did, but with one or two proper boards for it. Yeah, and while you’re at it, please add a smd-fuse as a short circuit protection like LegolasGT did. Yeah if we could have them all combined, would be neat, don’t you think so? But again, I was just joking around. I’ve yet to try out any kind of LTC, so which of your boards should I try?

I can draw a board in eagle, but I don’t know how to design a circuit. Mashm’s solution is awesome, but I would need some help to do that. I’m not really sure what the point of the fuses is though. Seems like it would add a whole lot of resistance.

Of my boards, it depends how many extra parts you want to buy. I suggest reading the LTC OP and last few pages of the thread to see the newest stuff

Yes, thought that too. But I liked the idea of an additional safety feature for high-drain-unprotected-cells-power-build applications. I think he came up with that in combination with his 3,7V->6V 3A-out boost driver, maybe it made more sense in an electronics-way with that driver.

Since there will be less glass to conduct heat, you should probably cover more area with copper when laying it out.
I just did a mod. where the driver had to sit under the pill, as sometimes done on SK-68s. A thinner board would have saved me some filing.