Have thought about building a sotwelder like yours so many times, because it seems to work well.
This arduino one looks like a fun project and totally doable. The costs are okay and if I fuck up I can live with it 
I already ordered the reichelt parts. They also have battery terminals for like 2,5ā¬ 
Do you still have a pack? I would need one sent to Germany.
Iām soldering some of the components to the PCB this weekend. I will post some pics.
How much you spent on mosfets and other little parts?
I might join in, if you dont run out of pcbās that soonā¦ Although, I have my own 5v arduino nano, so I would only need the pcb and perhaps footswitch, if the switch I found in a microwave does not fit nicely.
Although I am still a bit unsure of the spot welder ideaā¦ especially, because of the technique I found, where a small fuse wire is soldered directly onto to the cell, thus avoiding to excessively heat the cell or the cable to make a connection to the cellā¦
Will see with timeā¦ although my calculation was that diy spot welderās cost is close to 50 eur. Depends is it battery or transformer driven of course, but still.
Finished most of the soldering on the Arduino side. Need to get some aluminium sheet so I can start on MOSFETS.
Whatās wrong with it? I read somewhere (or on instructables?) that new pieces have a clip-type legs not only thick pass-through to secure it to the panels. Those legs are for removing twisting stress from connector legsā¦ Just squeeze those flat clips a bit or apply some sandpaper on themā¦
R, J.
The pins are rectangular now, not pin. I looked at the traces on the board and there are no traces to the side pins so I just carved out the pcb a bit. I think that is ok. Otherwise I have another PCB.
Yes, enlarging the holes would also help ā just make sure you have enough surface to solder it to the PCB. Those pins / clips are only to physically secure the potmeter to the panel and remove the twisting force from the normal pins.
R, J.
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Pictures of what? There is a video on how to make the spot welder. It isnāt too hard.
I will send a pic when I get home.
See the big side pins? They donāt fit in the circle on the pcb. Either sand the pins thinner or use an xacto knife to carve the circle out a bit bigger so the pins fit in. If you still need a pic, I will happily get one for you.
nah, everything is alright 
i just did not find the time to assemble mine yetā¦ Thank you very much!
No problem. If you need any other help just ask me. I will finish the PCB soon but wonāt be able to finish the rest until Christmas. Please show me some pics when it is done. Good luck!
Check out the diffs in size of the clip-legs - thick does not fit through the hole:
You have bought the parts from the bom of reichelt?
@kovjanos - thanks for making these available to everyone. Iām going to PM you to grab one or two. Iāll get the parts list from Mouser vs reichelt.de.
Sounds like a fun project - do you have yours complete and working well? Any issues or tips we need to know that have changed from the video?
Thanks!
I bought them from Reichelt. Cost quite a bit for shipping from Germany to Australia but at least I knew I had the right parts.