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

Can someone give me a brief of what happened in there? I never checked this thread to be honest and from the last few posts I read, I gather this project is currently ‘in waiting’? Thanks

Just discussion about the driver. People are still making improvements, but it’s ready to use.

+1. Part of the reason this driver seems like its in limbo is because the creator wight is taking a break from the hobby for a while. However there are some working versions of the driver listed, mine just above being one of them. Fully assembled drivers and parts kits can also be purchased from Mountain Electronics.

Thanks man!

I prefer the +1 7135 drivers at this point. Got pretty good, multiple versions of firmware supporting them. I like 5 modes on these, with moon and low PWM'ing off the 7135, medium is the full 7135, and hi PWM's off the FET, then turbo is full on the FET. You do get the tint shift going from med to hi, but I like having the 1st 3 modes with a nice tint and running very efficiently.

I have buyed v24 of the driver layout at Oshpark. Now its time to order the comonents. I’am very new in flashlights so I will make sure that I order the right parts.

C1 – 4.7uF [GRM21BR61E475KA12L]
R1 – 22k 0805
R2 – 4.7k 0805
D1 – SOD-323 & SOD-723, assorted
OTC – 1uf [C2012X7R1E105K125AB]
MCU – ATTINY13A-SSU
FET – PSMN3R0-30YLD

Are the size of the resistors proof? Is D1 a Schottky-Diode? I’am not sure?

Next Question: For Zener-Mod I have to place C1 at zener-spot and place the zener diode on top. Thats clear to me. But what about C1? I have to leave C1 empty? I have to change some resistors or other components for zener-mod, too?

Thank you!

Post #36 has the digikey cart list, repeated here: http://www.digikey.com/classic/Ordering/AddPart.aspx?WT.z_cid=Shared_Cart, though might be cheaper ordering the same parts on Mouser. Use these exact parts or exact equivalents, then there's no doubt.

Use the 10 uF cap, not the 4.7uF - 10 is what we all typically use, but wight said the 4.7uF worked for him.

Not sure bout the zener setup.

Thanks for the cart Tom! I found the correct link in #36. I will order 10uF!

Maybe there is someone who can help with zener mod.



If the version of the board you ordered is one of the early desings then yes. The old boards had a defect in the layout so in order to make them work the 10uf cap has to be placed on the zener diode pad with the zerner diode over the top. Make sure you get the diode placed on it in the correct direction. The end with the little stripe on it goes toward the inside of the board.

The other components that need to be changed for the zener mod are R1 and D1.

R1 will be replaced with a 36K ohm resistor and D1 will be replaced with a 200 ohm resistor. Notice that all resistors accept the D1 are in K ohm, and the D1 is just 200 ohm.

I hope this helps.

BTW, anyone know why it uses a 22k resistor instead of the 1912 we had been using before?

I’ve tried both, and I found that 1912 makes the OTC work quite a bit better. The 22k resistor puts the useful OTC values at the far edge of the attiny’s measurement range and makes the OTC timings particularly temperature-sensitive.

wight states in the OP: "My 22k R1 replaces the 19.1k R1 due to the change in how the divider hooks up to B+. 22k is not guaranteed to be perfect, but it’s close enough for me and for now".

It was supposed to compensate for the design change in order to keep the LVP values the same (130 and 120), but I usually use lower values anyway. wight's and C_K's board all had the design change - changed from the original Nanjg, and the original BLF DD driver (https://budgetlightforum.com/t/-/27210). On the Nanjg and original BLF DD, the Batt+ came after the diode, while on the new designs, it's direct from Batt+. The diode has a voltage drop across it, so maybe the theory was it would be more reliable without the diode? This goes back a while. I thought at the time, there was a good reason for the change.

No idea it effected OTC though -- if the 19.1K is better on this exact board design for OTC, I'm thinking it can be used, just that we would have to come up with different values to use for LVP, as long as it stays in range of course.

Ahhh - wight or C_K would know this stuff cold (both MIA), RMM would also probably know. There are a few others around knowledgeable on issues like this.

The only purpose for the 4.7K and 19.1/22K resistors is LVP, so these can be changed to anything as long as LVP can be made to work.

Sorry, made lots of edits on this post...

Thank you!

What firmware you guys prefer for this driver?

If you don't mind buying preflashed micros DrJones guppy2drv sold by RMM is a pretty good choice. Lot of options, and it uses the off time memory.

Thanks!

I need to get some 1912 resistors to swap out on my current drivers so I can test it, but from what I’ve seen so far the 22K resistor is a downgrade. Both allow LVP to fall into the useful measuring range, but 22K seems to mess up the OTC.

With a 1912 resistor, useful OTC values (0.5s and 1.5s, room temperature) are about 200 and 100, and after being left in a freezer the medium press takes 2s instead of 1s.

With a 22K resistor, useful OTC values (~0.75s and 1.5s, room temperature) are about 250 and 190, and after being left in a freezer the medium press takes 10s instead of 1s. In both cases, the value stays at 255 for a while before dropping at all, so shorter lengths of time cannot be measured.

I tried using the memory decay trick to measure shorter times, but it doesn’t work when the OTC is enabled. If the OTC has power, it will keep the attiny powered up enough to keep memory from decaying, so the shortest amount of time I could measure was like 4s with that approach.

interesting. I have been using 22k because that’s what wight recommended. R1 was the only thing changed between your tests?

Where do I need to look for problems with a couple of my drivers. They don’t have modes, just single mode.

I want flash them on my own.

STAR (or derivative) is what I’ve used

So the only way to get Guppydrv or Moppydrv is buying preflashed chips from RMM? There’s no way of flashing it yourself?

Thank you! I will give it a try. Does every Nanjq compatible firmware (for example NLITE) work with this driver?

Yes I think so. Because it isn’t open source.