Preview: Open source soldering iron driver v1.5

Today we sent our updated soldering iron driver v1.5 PCB to be fabricated. This is a 100% through-hole reroute of Arhi’s latest gen 3 design. The ground plane is broken into power supply, analog, and digital sections to help reduce noise. PCBs will be available in the free PCB drawer soon if you’d like to test it.

Version 1 was based on the gen2 driver designed by Arhi in the forum. Since v1 many bugs were found and ironed out. Version 1.5 is based on, and totally compatible with, Arhi’s gen3 driver and firmware. Here’s a list of updates in v1.5:

  • An 1mA constant current now drives PTC type sensors, clearing out the noise.
  • The DC/DC converter features an output filter, contributing to a cleaner power supply and more accurate ADC measurements.
  • The board is a two layer design, and ground layers have been separated between the power, analog, and digital sections.
  • Some footprints have been changed to more easily available packages.
  • Pins were reassigned to make V1.5 compatible with Arhi’s firmware.
  • There are now 6 I/O pins. 3 are reserved for the rotary encoder or interface buttons. The other 3 are free for development. Two of those are Interrupt-on-Change pins, and one is connected to the PWM peripheral’s output.

Join the Conversation


  1. It would be fairly easy to add hot air to the mix but the problem is that there really are no many hot air spare hand pieces out there. Also, for hot air analog control is more then enough so if you have hot air station there’s really nothing a “Better driver” can do for you

    1. I’m shocked they have no or few removable hand pieces. They could be available but with high cost I imagine..

      How do they handle failure or damage? Are the heating elements sealed somehow maybe so they don’t fail due to dust, or bugs and such things?

      There are three available IO, if there is ADC on one of the interrupt pins this is enough for air, heat and (one) temp. The power draw becomes an issue if you want to have an iron preheated, unsure which uses more they are close I think. Some add-on board maybe.

      Analog is fine generally, with digital there can be no “Did you touch my knob, again!”.

      Maybe a digital ramp preheat, flow, and cool down, for “controlled repeat” as uses?
      Add a trigger on to a hand-piece, add indicators, control ware and you get..

      . push button “Wave magic wand” listen/watch/feel “Tap magic wand” listen/watch/feel “wave again” l/w/f *Poof* Fully flowed, pass to next guy for testing and repeat! This frees up the the mind to wander ,and only mind fingers and for flames, and also makes for nice marketing.

      Add a sonar module and it could vary air flow with sensed distance for even less guess work by the operators.

      1. “How do they handle failure or damage?”

        You can easily disassemble most hot air gun’s to replace heater but the hot air assembly does not come with a connector but the tube that holds air and wires goes directly inside the “box” and there’s connected directly to driving circuit and pump. The other issue with hot air is the pump itself as they are not that easy to get so it’s actually easier to get a working hot air tool then to make one

        The board itself as is ain’t really useful for running iron + hot air in the same time. It could be done with some easy tweaks but in that case I’d make a board that reads specific sensors, so for e.g. 2 RTD’s or 2 TC’s or 1 RTD and 1 TC, so you would have to know in advance what type of iron and hot air handle you want to use… also you need 2 triac’s or 2 fet’s depending on if you are driving them DC or AC ..

        The rest of the comment is about “building your own handle” … after testing a lot of hand pieces and disassembling most of them I have a pretty good idea how to make both iron and hot air toom myself. It’s just something that’s really not a “hobby” thing. If one want to enter the “soldering station making business” yes, but I had my business for many years and it’s not fun and games, the RND / interesting stuff is less then 1%, 99% is politics, taxes …

      2. …but there are *cheap* spare part for the soldering stations available…
        I’m using some Aoyue brand clones (identical to HAKKO etc) and their spare parts are relatively cheap – you can get the antire hot-air handle (with heater etc) under 30€ with taxes included! On the other side, the entire soldering stations are also cheap… so it’s maybe better to take a cheap station and do some ‘lift-ups’
        check for more details.

  2. Excuse my ignorance. Is there something peculiar about a soldering iron driver that lends itself to a through-hold design over a SMD design? I was trying to fix my Aoyue 937+ a while back and noticed it was all through-hole. I thought that was odd for a relatively recent design. Any thoughts?

    1. The idea to make this design trough hole is so that anyone with “any” soldering iron (even shitty 1$ irons) can solder the components and get him self a usable cheap soldering station.

      The reason why bunch of cheap drivers are trough hole is price, they mostly use single sided boards (way cheaper then 2 sided ones) and trough hole components.

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