USB-C-PD Soldering Pen Is a Compact STM32-Powered Solution for Weller Tips

Nothing beats a good soldering station with adjustable power and interchangeable tips, which can be found on nearly every workstation. They are an invaluable tool for everything from PCB electronics population to making stained glass windows, and everything in between. The only drawback soldering stations have is their portability, as they need a wall outlet for power.

That aspect alone has given rise to portable soldering irons that take advantage of USB Type-C ports that can draw power from laptops and mobile power supplies. They are also seemingly keeping the 3.5mm jack alive through the use of interchangeable tips. These types of soldering irons can fetch a hefty price, which is why electronics engineer Thomas Leputsch decided to design his own with the USB-C-PD Soldering Pen that uses Weller RT tips.

Leputsch explains, “The intention for this project was to build a cheaper and even more compact controlling unit for the — in my opinion — best soldering tips for small and medium-sized soldering joints.” The USB-C-PD Soldering Pen was designed using an STM32F042G6U6 MCU with Arm Cortex-M0 processor for controlling the temperature profiles, and an STUSB4500QTR for the USB power delivery controller. Leputsch implemented the USB PD 3.0 standard with 9V/3A for the power supply as well.

Powering the USB-C-PD Soldering Pen can be done using any USB-PD power supply — including mobile banks and even laptops that use USB Type-C power supplies. The soldering pen is outfitted with three LEDs that indicate different power profiles (low, medium, high), which can be selected using a pair of buttons located on the handle. The heat-up time is impressive, going from 25°C to 350°C in just six seconds, and it idles at 180°C in standby mode. Those interested in recreating his build, Leputsch has uploaded a detailed walkthrough on his project page.