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

Flashlight Modding and DIY Parts
576

Yes, for connection see this picture http://drjones.nerdcamp.net/lumodrv-connect.jpg

577

Solder it to the OTC pads

578

If I recall correctly, this driver has an unused pin, pin 3 (a.k.a. PB4). At least, that’s the unused pin on wight’s FET+1 driver. I think he used the same pin layout here, except for not using the second PWM channel.

So, if you configure your firmware to put the switch on PB4, and solder the switch wires to pin 3 and ground, it should work without sacrificing the OTC.

In the OP, it shows pin 3 next to the “W” in “WELLS”.

Or, of course, if you don’t care about the OTC, use those pads instead. OTC isn’t normally used with e-switches, and this will make it a lot easier to flash the driver again later.

579

Ok, thank you! Can I use the Standard firmware when I use the OTC pad? OTC goes to Pin2? I have to solder the switch to both ends of the otc place?

Maybe reprogramming to pin3 is also a good idea, I will think about it. Thank you very much!

580

Not sure if stock uses that pin the way you want, but changing a pin is usually as easy as changing one line of #define near the top of the file.

581

Ok I found it, but sodering to the pins of the attiny makes flashing on the board complicated. So using the otc pad is for me the way to go I think.

But I am not sure with the otc pads, are they connected to pin2 (#define SWITCH_PIN PB3)?

582

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

Is it necessary to leave c1 in place when i place a 10uF Cap on the zener place with a zener stacked on top?

Why is it better to replace R1 with 36K, the picture show a 22k resistor?

Thanks!

583

Which board revision are you building? You shouldn’t need two 10uF caps but I haven’t tried just one on wight’s board. I use RMM’s boards (from his MTN store) and you only place one 10uF.

The 36k resistor isn’t required if you already have a 22k. It just gives you more options with the ADC calculation for the LVP (low voltage protection). With the 22k and 2S (~8.4V) you end up being in the upper range of the ADC (limit of 255) with 6V LVP. If you wanted to have something higher for your LVP like 6.4V you would need the 36k resistor. You can see the calculations on RMM’s Google sheet that he so nicely shared with us before:

If you look, the 36k brings the ADC values more into the middle rather than the upper limit.

584

Ahh I understand. Then 36k seems to be very usefull! And the calculations, too :wink: Thanks!

I use this Layout (should be the same like in the picture here: 17mm & 20/26/27mm single-sided DD/FET driver release: A17DD-SO8 / A20DD-SO8 / etc):
OSH Park ~

I’am not sure now, if one cap 10uF is enough….

585

One 10uF should work. On the board you linked to, place the 10uF on the zener pads then stack the zener on top of the capacitor.

586

Thanks Richard! I will give it a try :wink:

587

The Zener direction is the same like printed on the layout? Cathode points to R2?

588

Yes, same as printed.

589

Works like a charm! Thanks

590

https://oshpark.com/shared_projects/OODIn7Cf

Can somebody confirm this as a working zener-layout? (no workaround)

591

Does anyone happen to know what could be causing one of these drivers to change modes on its own?

I made 50 of these last batch and they all work fine normally. I had even used one of them with an eswitch in the past and it was fine. However recently I tried using JohnnyCs dual switch firmware with them and this is what I get.
https://youtu.be/vw5rxIBh7_M

It will just sit there and skip upward in modes at random on its own. I tried multiple drivers and even assembled a brand new one and the result is exactly the same. I tried both 6 and 12v configs too with no luck.

I tried using the default firmware from JC and TomEs eswitch one and they both skipped. I had used toms before too and did not have this issue so the only thing I can think is that I was shipped a bad batch of components. Problem is I have no idea which part could cause this :(


Any one got an idea?

592

Hhmm. I watched the video 3X, not sure wut could be goin on. It seems very periodic and relatively slow, I think... What kind of setup to you have there? Think I saw 4 cells in series, so 16V going into the driver? Wow... With an e-switch, I assume you are using an LDO?

The pace seems like LVP is kicking in, but it's going up not down... But if it's acting like a click is happening, I suspect something unreliable bout the switch input, but you are grounding it manually. Dunno, I'm no expert there in electronics. Maybe the voltage the MCUU is getting? If so, maybe the LDO that supposed to regulate that voltage? Again, I'm not sure exactly how an LDO works, but it's supposed to deliver the correct voltage to the MCU. Maybe you can check that voltage level on the MCU VCC pin #8?

593

Is this still the preferred parts list for a 1S V044 board?

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=48a3801cb6

Thanks Matt

594

I've almost always only seen that happen when the driver is glitching due to a dirty VCC signal. How is your circuit set up?

595


By dirty VCC you mean like a trace that is too close to something else? By circuit setup you just mean a picture of the underlying traces right? If so I will try to do that tomorrow.


I also have one other pressing question if you don't mind.


I have tried to use firmware that has a strobe function with these drivers, and on both the 1 and 2 cell board the strobe and SOS sequences are very very slow. I have tried 2 different firmware's which I know to be good with 7135 boards and the result is the same.

Any idea why that might be?