Soldering iron mod help required

Hi, I am pretty new to this community but have seen a little project that I would like to try.
I have a 60w temperature controller soldering iron(when I say temperature controlled I mean the potentiometer is on the iron handle itself)
The project I am currently following is to convert my iron into a Hako907 style iron with the use of Arduino Nano board and LCD.

My issue is as follows.. I don’t want to really spend out too much money so would like to modify my current soldering iron.
I wish to bypass the potentiometer on the iron since the temperature control will be on the enclosure instead.
(The device I’m building has the ability to show working temperature and preset temperature)
Sorry for long message but how can I bypass the potentiometer on the iron so it does not interfere with the Nano controlled device.
Many thanks

how can I bypass the potentiometer on the iron

Well it depends on the iron - but why not just turn it up to full?

The project I am currently following is to convert my iron into a Hako907 style iron

link please, I dont know what that is.

How are you intending to measure the temperature of the iron ?

Hi John,
I actually never thought about turning it up to full and locking it off with glue, I guess to stop it from adjusting (by accident) when holding the iron.

Here is the link and it is a simple to build mod... I was just stuck with the potentiometer on the iron.

Have you got a Hakko 907 or similar handle such as the one used in the project that you linked to ?

No I don’t have a Hakko 907 iron but I do have a replica and I know it works because another message board thread but on a different site has almost exactly the same iron handle as I have and has no problem with it. His one however is slightly different to mine in respect that it does not have adjustable temperature control (which is why I was reaching out for advice on what to do with the POT)

In your original post you said

the potentiometer is on the iron handle itself

but the Hakko 907 style handles do not have the pot on the handle

In order for your project to work you need to be able to read the temperature sensor in the iron and to control its temperature by using PWM on its power lines. How many wires come out of the handle and what are they connected to in the handle ?

Hi Bob,
I think I see the issue now. I will invest in a Hakko iron instead.
Thanks again though for your help

You can buy "Hakko" 907 handles quite cheaply and build your own control system if that is what you mean

Good luck with your project

Hi I have located the Hakko irons but struggling to track down someone who can produce the one off PCB board and plastic enclosure.
Do you have any suggestions?


I get PCB's from PCBWay or JLCPCB which can be quite cheap

I just have bought a complete Hakko clone kit (without case, nor 24V Power supply) for less than 12€.
What could you expect cheaper?

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