The current generation of USB-powered soldering irons have a lot going for them, chief among them being portability and automatic start and stop. But an iron that turns off in the middle of soldering a joint is a problem, one that this capacitive-touch replacement control module aims to fix.
The iron in question is an SJ1 from Awgem, which [DoganM95] picked up on Ali Express. It seems well-built, with a sturdy aluminum handle, a nice OLED display, and fast heat-up and cool-down. The problem is that the iron is triggered by motion, so if you leave it still for more than a second or two, such as when you’re soldering a big joint, it turns itself off. To fix that,[DoganM95] designed a piggyback board for the OEM controller with a TTP223 capacitive touch sensor. The board is carefully shaped to allow clearance for the existing PCB components and the heater cartridge terminals, and has castellated connections so it can connect to pads on the main board. You have to remove one MOSFET from the main board, but that’s about it for modifications. A nickel strip makes contact with the inside of the iron’s shell, turning it into the sensor plate for the TTP223.
[DoganM95] says that the BA6 variant of the chip is the one you want, as others have a 10-second timeout, which would defeat the purpose of the mod. It’s a very nice bit of design work, and we especially like how the mod board nests so nicely onto the OEM controller. It reminds us a little of those Quansheng handy-talkie all-band mods.
so i guess i missed the import of this innovation but it sounds like now you can get soldering irons with the c210 super light tips for like $50? and the only downside is they have usb-c and some mildly frustrating grounding hack? and they heat up in 3 seconds??? it sounds like the sequre s60 has a configurable up to 60 second time out on motion.
it took me years to realize that i am absolutely destroying my tips somehow and now they have an iron that turns off when you set it down and comes back on in just a few seconds. i’d feel stupid spending more money on this problem given how little soldering i do but this is a game changer that i had somehow not noticed. an on-demand iron! my dad showed me one of these that his employer bought, and it seemed so whacky to me and now it’s just another cheap thing neat!
Once I got my Metcal soldering iron, it was a game changer. Since temprature overshoot is nearly non-existent, lifted pads became a thing of the past. The tips last far longer as well. One time I left it on overnight. No damage to the tip beyond a layer of oxidation that could be scraped off.
If you do a lot of soldering, an iron with a directly heated tip is worth it. Or in the case of Metcal, RF heated.
Most of these trendy portable soldering irons seem to have at least one major flaw.
Hopefully there is one out there that just works, and doesn’t require modifications to be useful.
Funny, my 20+ year old Weller uses heater current to determine whether the iron is in use or should turn off. That would seem like an entirely trivial thing to add to a “smart” iron.
Why would you need to go through the nonsense of “touch” sensing when you already have a perfectly good sensor to tell when you are touching something (the heater control loop)?
Modern soldering irons turn off entirely when not being used, since they can get up to temp in 1-2 seconds (the time it takes to pick up the iron). Typically they turn off when set into the stand but for the portable usb ones they can’t do that since there isn’t a stand.