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Solder Ninja Pen

A 45 W USB-powered soldering iron compatible with Weller RT Micro tips

Limited items in stock

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May 02, 2025

Project update 5 of 5

The Latest Design and Production News

by Nicolas Schurando

Hi everyone!
Here’s a quick overview of where things stand and what’s happened since the campaign reached its goal.

Shipping Delay

First off, I want to acknowledge that delivery will be delayed — probably by a month or two. There are a few reasons for this, all of which had a cascading effect on ordering parts and kicking off production.

Design Updates

But I’ve been using the time to make sure the design is as solid as it can be before pulling the trigger. Thanks to a helpful comment from the community, I discovered that under certain conditions — specifically when the tip is hot-unplugged — the voltage intended for the heater could momentarily short with the thermocouple signal and stress the analog front-end IC well beyond its limits. It wasn’t something that showed up in normal use, but definitely something that could impact long-term reliability. So I decided to go through (hopefully) one final PCB design iteration to add proper protection circuitry.

Certifications

One thing that’s been keeping me really busy is certification. To help navigate the regulatory maze, I got in touch with Clemens Mayer — a fellow maker who’s launching a consulting company to help small hardware projects get CE certified. His input has been incredibly valuable in identifying all the applicable standards and their various requirements in terms of documentation, testing, and labeling. If you’re interested, feel free to check out smander.com and their Discord server.

Sourcing

On the sourcing side, I ran into an obstacle with the original supplier of the plastic buttons (JLC3DP), as they weren’t able to provide the necessary RoHS and REACH documentation — which is essential for that part of CE compliance. I’ve since been reaching out to alternative suppliers who can provide proper certification. I’ve identified three promising options and am currently waiting on samples.

Firmware Improvements

Meanwhile, I’ve also been improving the firmware. Some USB Power Delivery sources were randomly resetting the iron. As some of you may know, USB PD is pretty strict when it comes to timing — messages need to be acknowledged in under 195 µs, which the FUSB302 takes care of, but replies handled by the firmware must come within 15 ms. To keep things simple and easy to maintain, I wanted to avoid pulling in any form of RTOS due to the learning curve and hidden complexities. But as features and debug code accumulated, the timing started to slip. So I refactored parts of the firmware to be more cooperative. That fixed one issue — but also exposed another: the firmware didn’t handle unexpected PD messages gracefully. I ended up improving the messaging stack to be more robust overall. It’s still not perfect, and I may revisit it again post-release, but it’s in a much better state now.

Cable Production

Production of the silicone USB Type-C cables is complete and they should arrive within a week. While I have the theoretical folded dimensions, I’ve been waiting to get a sample in hand before deciding whether to slightly adjust the packaging size.

Thank You!

Thanks so much for your continued patience and support. I know delays are never fun, but I really want to make sure you receive something reliable and thoughtfully engineered. As always, feel free to reach out if you have any questions — or just want to chat.

Regards,
Nicolas


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