USB-C-PD Soldering Pen for Weller RT Tips

Small and powerfull controlling unit powerd from USB-C-PD

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This is my project to build a controller unit for the Weller RT-tips.
The intention for this project was to built a cheaper and even more compact
controlling unit for the - in my opinion - best soldering tips for small and medium sized soldering joints.

By the time this project wasn't cheaper than buying a finishend Weller station, but I still have lots of fun working on this Project and have a controlling unit which exactly fulfill my needs.

Enjoy looking around on my project page and feel free to like and leave comment!
Ideas for improvements are welcome :)

I have used the PD 3.0 with 9V/3A for supply. It can be powered from an USB-PD power supply (even suitable laptop USB-C power supplies) or with an PD-Power bank for soldering on the go.
The heat up time from 25°C to 350°C is around 6s. Auto-standby temperature is around 180°C, by picking up from the rest around 3s are needed to reheat.
The user-interface consist tree LED's and two buttons. The LED's indicate which temperature profile is active (Low, Mid or High) as well as the operating modes (user-standby, auto-standby, auto-off, warm-up and overheat). 

Its simple! - If any LED blinks, the Soldering Pen is not ready or at the desired temperature range. Steady light than means that the pen is ready.

I have chosen the simple 3-LED-Display because there is no need to set or know the temperature in 1°C steps. There are three basic groups of soldering types:

- Very sensitive components(e.g. temperature sensors)

- Regular sensitive components and Wires (e.g. Resistors, Capacitors, most types of IC's)

- Not sensitive parts (e.g. large copper areas)

Based on this knowledge I implemented the three profiles.

One button controls the user-standby mode the other changes the temperature profiles.
The pen fits perfectly in the original Weller safety rest WDH 51.

Here are the video demonstrations:

  • 1 × STM32F042G6U6 MCU
  • 1 × DMC1016UPD-13 Dual Mosfet
  • 1 × LM3480IM3-3.3/NOPB 3V3 regulator
  • 1 × F721A108MMCAQ2 1000µF Cap
  • 1 × STUSB4500QTR USB Controller

View all 6 components

View all 7 project logs

Enjoy this project?




[this comment has been deleted]

thomas.lepi wrote 05/02/2019 at 07:59 point

Hi, thanks for your offer! By the time you can support me by liking my Project due to ongoing Hackaday Price 2019.

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Tom Kelley wrote 04/22/2019 at 04:07 point

How are you powering the tip? Square wave, sine wave switched at crossing, something more exotic?  I want to try something like this, and I want to design it myself, but I want to make sure to do it right. Seems like you're doing this right. Good project, BTW. :)

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thomas.lepi wrote 04/22/2019 at 09:11 point

Hi Tom, I‘m glad that you like it :-) 

I used a PWM, but it’s important that you not read the thermocouple voltage while the heater is on. Watch your tip carefully when testing because it takes seconds to  damage them irreparable ;-) 



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Tom Kelley wrote 04/22/2019 at 14:41 point

You're the man, man. 

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de∫hipu wrote 04/15/2019 at 16:40 point

I'm so waiting for this! I already use weller tips anyways, and it would be nice to have a portable iron I can use with my laptop charger.

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whmeitzler wrote 03/01/2019 at 20:18 point

The cable that came with my old Nexus 6P is very likely silicone, though I haven't iron-tested it.

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thomas.lepi wrote 03/01/2019 at 21:28 point

Thanks for your hint but unfortunately i cant find information on this cable.

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Killergeek wrote 02/27/2019 at 18:35 point

there are USB C connectors that have power, USB 2.0, SBU and the CC lines only. makes it smaller and easyer to solder. if you dont use any of the USB 3.X stuff that is a better option.
sparkfun has them
you can google for them with "16 pin USB c connector"

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thomas.lepi wrote 02/27/2019 at 19:09 point

Thanks for the information. I don’t know them yet. If they are easy available I will implement them in the next version if the PCB because it saves me the reflow soldering step :-)



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Larry wrote 02/27/2019 at 18:28 point

Nice work!  From digikey, but TPE cable insulation and max temp 85degC.

Another idea is use metal braided cable, but not so flexible probably. And could not find c-to-c in my quick search.

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thomas.lepi wrote 02/27/2019 at 19:02 point

Hi Larry, 

Thanks for the links! The metal one looks quite stiff. But the outher could be an option for usage with Power Bank because ists just 1m long. 



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thomas.lepi wrote 02/12/2019 at 18:40 point

Hi Mike, I can't reply your comment.
A basic serial communication for data output and maybe with GUI configuration of temperatures, auto-standby time, vibration sensitivity etc..

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Mike Szczys wrote 02/11/2019 at 23:23 point

I feel like there must be cellphone MFG cables that are USB-C and silicone insulated but don't know for sure (my Pixel cable is not).

Would love more information on this. Is it a pain to work with those connectors? How about negotiating with the power supply.

Demo video and case looks great! You could put a rectangle of tinted acrylic over the flat area of the pen with beveled edges and holes for the buttons and you'd have a killer finish!

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thomas.lepi wrote 02/12/2019 at 06:43 point

Thanks for your comment! 

For soldering the USB-C connector an oven is needed due to the inaccessible pads in second row. I’ve used a stand-alone controller for negotiating the supply - it was a bit tricky to configure but finally it worked good. 

More information is coming! 

New 3D Print Design and hopefully a working USB 2.0 communication via the USB C Port. 

Its planed to cover the full flat side with a sticker but in this version I’ve just used the middle part to hold the diffuser in place. Maybe I can implement a tiny sticker on top of the buttons. 



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Mike Szczys wrote 02/12/2019 at 15:34 point

Oh, interesting. What kind of functionality do you have in mind for the USB 2.0 connection?

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