Oshpark Projects

That's a steady learning curve you are having, Dale ;-) , and I appreciate it that we all get to follow it (board without minus-ring and ATiny upside down in one picture )

Heh. :O

I bet the MCU still works after you turn it around. And if you got smoke, then the diode is at least able to pass electricity, see how it does before giving up on it. If it works the same it really doesn't matter, as long as it fits. If it's hard to get lined up on the existing tiny little pads, you can scrape off some of the mask over the trace to extend it out a bit.

I've been hacking away at them for the past two days, I think 3 boards are now totally destroyed (the components are still OK though, just too much soldering and scraping and soldering again and again...). Good thing they are cheap. And also that they are the alpha versions before the tweaks and updates.

Yes, neither resistor alone will make it work right - at least not with the fast PWM firmwares, which has been the main drawback to these things from the start. The resistors fix that.

The BLF comedy hour is proud to present, Dale the advanced learning curve electrician/comedian! Woohoo!

Ok, hi everybody. I’m Dale and I’m a flashaholic. A stupid one. :slight_smile: But hey, I’m also a SUCCESSFUL one! :slight_smile: I pulled the ATiny from the new BLF FET 17mm DD board and reversed it. Worked out pretty well. I pulled a 200 Ohm resistor from my Zener kit and stood it up, held it in place with tweezers and soldered it under the previously prepared PWM leg of the FET. Simple enough, the Hakko work station makes all this pretty simple, even for a rank amateur like myself.

Now for the fun and games! I soldered the power leads to the test emitter and, with my DMM between, applied power. Smoke! Aiiiiieeee! (Hooked the incoming power leads to the emitter, outgoing to the cell) Oops!

Ok, situation corrected. wired up properly now it’s gonna work right? Uh, well, seems like the little hemostats are clamped on the positive pad and negative ring at the same time. Little sparks dance around the outer thin ground ring towards the positive pad and smoke curls up! Aaaaaiiiieeeee!

Ok, now, everythings clear, we’re good to go (man I’m glad I’m using a 18500 lap pull here and not a Sony C5)

4 levels from .05 to 4.40A with nice even positive switching. Whew! Finally!

Ok, yes, I’m embarassed. But hey, it could happen to anybody! And probably will happen to a few of YOU! So I wrote this to make sure y’all are dotting your i’s crossing your t’s and minding your p’s and q’s. :stuck_out_tongue:

(And I just found out that minding your p’s and q’s is in reference to tending your own Pint or Quart of Ale, so cheers!)

See, I told you those little things are practically unkillable.

I think the only form of torture you left out is connecting it to household 115VAC! lol :D

When I hooked it up to my big jumper cables and the car battery, it got difficult to see anything for all the smoke, but the emitter still didn’t shine. Oh well. :stuck_out_tongue:

See how much I learned? Know how long I’ll remember any of it? lol

Wish I had some sort of excuse, but Stupidity is about all I can blame it on. But hey, I got there in the end…that counts for something doesn’t it?

So, now y’all are probably gonna tell me that I should open up my M8 and C8 and 7G5 and L2P and fix them with the resistor between the PWM/FET, right? Scares me, they’re doing so well…do I HAVE to?

Nope, no need if they work with the firmware you have on 'em. For some reason the FET stuck on the 105C board doesn't have the issues with mode changing/acting goofy, that seems to be only on the new boards. Which is really confusing. It's not because of traces too small, I jumpered over all of them point-to-point last night and it made no difference whatsoever.

Could it be something about the different MCU - the SSH we're using here instead of the SSU that comes stock on the 105C? Maybe even something undocumented, or not listed in the main specs but hidden away somewhere in the datasheets?

I was playing with the test emitter, still using the lap pull 18500, and it was working perfectly. I held different levels with no problem, switched easily and repeatedly and did everything but run it on high for any great length of time. While my test emitter is mounted on copper in a fairly heavy aluminum pill, just didn’t see the need to run it prolonged at high level.

I did want to see if moon mode works. (Read, Oh Ohh!) So I soldered the #2 position to the mcu and tried it. Nada. Not even smoke or sparks. Simply nothing at all. I removed that jumper and still nada, nothing, zip, zilch. That was the ONLY thing messed with, and removed it still is non functioning.

My head hurts.

You' re a hero, Dale, going through all this and solder your way to victory, and so is your little driver board

Actually, I left Victory behind…I used to live on Victory St. No lie!

I went back to the test rig and looked closer at the board, the tiniest of slivers of solder was still between the 2 pad and the mcu, so I picked that off with tweezers and it now works again! The number 2 position, engaged, kills it dead. Open, it works fine in 4 modes. What’s up with that?

Looking back at the pics that Comfy posted, with a mouse-over showing where the traces are…that “star 2” position grounds the PWM leg. Why?

Where do I find information on what the “Star 2, 3, 4” are for?

The Star 2 is supposed to go to leg 5 of the MCU, not 6. Leg 6 controls PWM.


Borrowed this from Comfy earlier in the thread.

Might be so low that it “looks” dead but really isn’t

I have a cheapy XM-L that I flashed STAR V1.1 on a true 105C…in moon mode, it lights the LED, but just enough to make some light…you can look at the emitter and NOT hurt your eyes…any other setting and it glare blind yourself

Since the PWM of moon mode is like 3-5 of 255 the FET might not be able to open fast enough…thus no current flow

Correct, there's a mistake in the solder mask. Just scrape off another little spot above pin 5, there's a big ground plane above both pins.

Also, the old 105C 'napkin diagram' pic has the stars numbered from right to left, instead of left to right. I always count the dummy that goes nowhere as #1.

Hmmm, 28 posts since I last got on here.

Can someone summarize what I need/should/could change if possible? And on what boards?

- Matt


EDIT: I see now. Add provisions for two resistors on the FET gates on ALL FET based boards. If they fit....if they don't fit then what (thinking the Tiny15 just won't be possible)? I'll also fix of the P1/2 pads on the SRK FET driver. If anyone has been financially put out by some of these minor oversights please PM me and I'll replace your boards with new ones for free.

I'd like to see an in-line resistor pad (0805 SMD) for the FET gate, possible a pad for a pulldown resistor for the FET as well. Maybe two versions? I know that some would like the simplicity of using without any extra resistors or jumpers, but they seem to offer some benefit for some situations.

0805 resistor between GATE & GND (easy), 0805 resistor between PB1 & GATE (erm, not so easy, at least on the 17mm). I guess all of them using the TO-252 FET need those, the 46, 20, & 17mm.

17DD has the ground pad for pin 5/star 2 over pin 6 instead, just needs a tweak of the solder mask (might already have been done on the rev.2 boards, I haven't looked yet).

SRK FET board could really use a change to the switch input pads, something like this

I don't think the tiny little FET on the 15DD board needs the resistors, same as 7135s don't need them. I haven't pulled up the datasheet on that FET though.

Pfffft, stop that. We're participants, not customers. lol.

No, the FET will open at lower PWM values than when using 7135s. They usually don't work at 4 or less, the FET works all the way down to 1.