The project involves a DIY high-frequency soldering station inspired by Metcal technology, featuring USB-C power delivery and battery support. The developer designed two versions: the main Hot Wand and the Hot Wand Lite, which integrates a circuit from Radio Thermal. The station operates at 13.56 MHz, similar to professional Metcal equipment, while the Lite version utilizes a 470 kHz frequency.
To ensure safety and compatibility, the developer implemented a USB-PD controller and an ideal diode controller to manage power flow between the USB-C source and the battery. The circuit is designed to handle input voltages up to 34 volts, accommodating high-capacity 8S batteries. To prevent current spikes and sparks when connecting batteries, the system uses a dual-MOSFET configuration that limits inrush current.
The power management system includes firmware-based power limiting to maintain compatibility with 65W USB-C power adapters. The developer also incorporated active cooling with 40mm fans and custom heatsinks for the MOSFETs. The final enclosure is 3D-printed from PETG, featuring a specialized air duct design to ensure efficient thermal management without direct contact between hot components and plastic.
The station includes a current transformer that functions as a phase detector to monitor the power factor. This allows the system to adjust output voltage based on the temperature-dependent reactive resistance of the soldering cartridges. All project files, firmware, and documentation, including thermal test results and circuit analysis, are available in the developer's GitHub repository.
