Try to program the tiny841 without anything else on the board. The other parts could stop the USBasp from recognising the mcu (at least that’s what helped in my case with a tiny85).
I tried switching the voltage several times, no response.
PM sent 
I haven’t tried that yet. I do have vcc, miso and mosi connected directly to the mcu at the moment because those 3 pads ripped of the pcb from me moving the wires around to much. I will try direct connecting the other 3 and see if anything changes. Thanks for the suggestion :+1: .
moderator007, did you get programmer to work? I am going to begin programming soon when I get the pogoprog pcb. the mcu is so small, it must be very difficult to solder wire directly to it!
You just need the right tools for the job! Lol
Yea no skill involved or nothin… Slather up that QFN with some solder and stick a couple wires on there with the ol’ sausage fingers.
I finally got the 841 programmed using a usbasp programmer. Some idiot had 2 leads out of place on the usbasp header. 
Sometimes the simplest things can be over looked, I checked the pin outs a half dozen times I bet. 
You will need to add the config patch file to avrdude for the 841 before it will work, avrdude doesn’t have the 841 specifications in the original config file… When I finally figured out I had the usbasp pin out wrong, avrdude found the 841 and programmed with no problem.
Tested the driver with a power supply for function everything checks good. I’m going to try to get the GXB172 installed in a S2 tonight.
Thanks for the help and the suggestions guys, greatly appreciated.
This driver really isn’t that hard to build but it is challenging to say the least. I built a second one last night in about 4 hours with a few family breaks here and there.
This time I reflowed the entire coil side in one season and then did the entire battery side at one time all but the op amp. Loneoceans has a noted the op amp is sensitive to heat and may not work correctly if overheated. So I reflowed it last by itself as quickly as possible. To me the temp sensor is the hardest part, it’s so small you have to use magnification just to see the pin reference dot for correct placement.
Thank you Loneoceans for sharing this fun and incredable driver project. 
:+1:
I did get it to work.
Soldering wires directly to the small pcb pads is difficult but soldering directly to the tiny mcu pads is even more FUN (I’m Joking of coarse). :confounded:
If you have a usbasp, you shouldn’t have to build the entire pogoprog board.
Mr. Moderator007, big congratulations to you!! This is another amazing result and I am very inspired by you and schizobovine for finishing gxb172 to motivate me to build also.
To build another one in 4 hour is another amazing result! I think I already spend a lot of time on just the driver soldering, but you are correct I think soldering with needle tweezer, hot air, and magnification is very important for this project. The temp sensor I use no solder, just a lot of flux and it seem to solder properly after inductor solder on.
Mr. Moderator007, I borrow ATMEL ICE programmer from friend and I will use Atmel Studio to set fuses on 841 and to program the hex file. Hope it will be able to work very soon!
Orsm effort moderator007. Well done. 
Thanks for nice comments, I have seen your Orsm work MRsDNF.
I finally got around to getting this mounted in a S2 (works been crazy last few days).
This is a Orsm boost driver. I’m charging up some 30Q’s to test output with.
Already saw 2500 lumens on a partially charged 25R with the default setting.
Soldered the two bridges for the 5.5 amps output. Just waiting on the 30Q’s now.
You probably mentioned it but what led are you using?
Anyone willing to piece one together and sell it complete for the souls who simply do not have the skill required or programming knowledge and tools?
Is source code for firmware available?
That’s what I really need. I’d like to tweak it a little.
I’m using a xhp50.2 J4 5000k on a copper Nitro sinkpad (The BLF created first ever sinkpad).
I’m really not sure if I’m allowed to sell one. That be a question Loneoceans would have to answer, not sure of the licensing.
A giveaway I could do? I have 3 more boards and components ordered, when I get time to complete them, I could do a giveaway.
There are two more of Mountain Electronics boost drivers available:
By the way, I charged up 2 30Q’s and one 25R. I got 2800 lumens at start up and holds 2500 lumens for maybe a minute (didn’t time).
I tested the current draw with a 87V and it said around 13 amps but the meter gives me a error because the limit is 10 amps so I wouldn’t completely trust that.
This driver also works with a lighted tail cap, no modification needed.
The stock switch also seems to handle the current fine for now. Part of that comes from Loneoceans firmware that ramps up from the previous level instead of just a full on.
Its like a soft start feature to each mode. Time will tell how long the switch will last at this current.
A GAW is incredibly generous, but I’m sure EVERY member on BLF would want to win so I’d be quite low odds to get it hahaha If you sold it what would be the cost? I could pay for your labor/time and you do the board and components at no profit.
I was racing in NC in 2006, I stayed in Apex, NC. I enjoyed it there, the people really made me feel at home.
Great work moderator007 to get loneocean’s awesome design to work.
I feared that this would stay a one-man’s project but thanks to you and clientequator and schizobovine this design slowly is getting available to the BLF community. And thanks loneoceans for making your driver public.