We're getting close to releasing the final version of Dr. PD! We've been doing a ton of testing with our beta testers, fixing bugs, and working on the user interface to make it easier to get started when you first install it.

What we've learned from beta testing

Our beta testers have been a huge help. Not only have they helped us find bugs, but they have also shown us how Dr. PD performs in different applications.

Some of our testers work with USB-C hardware. They helped us uncover unusual corner cases where Dr. PD wasn't interpreting the USB-PD protocol correctly, and their feedback helped us fix those bugs. Of course, testing also worked in the other direction: Dr. PD helped them find bugs in their own hardware, particularly in more complex areas like Programmable Power Supply (PPS) and Extended Power Range (EPR).

That was especially encouraging. Beyond helping us improve Dr. PD, these tests showed that it's useful for the development and debugging work we built it for.

Other testers were primarily users of USB-PD equipment. They used Dr. PD to investigate faults in their power supplies and figure out which supply was right for a particular job. Battery-related applications were a good example: characterizing how a supply behaves can help determine whether it will properly support the intended application.

A big thank-you to everyone who has tested Dr. PD and shared feedback. You've helped us make it better.

Making it easier to get started

Alongside the testing and bug fixes, we've been putting quite a bit of work into the user interface. Besides building a really useful USB-PD protocol analyzer, one of our objectives was to build a device that would be as close to true plug-and-play as possible; Dr. PD doesn't require installing any client-side user software or drivers, and even tells you how to connect to it when you plug it into your computer.

More recently, we made a few more tweaks to make a new Dr. PD useful right out of the box. The default mode is now Observer rather than Disabled, and captures are on by default, so users can plug in a source and sink and start seeing USB-PD messages right away. Previously, testers were plugging their devices into a brand-new Dr. PD and wondering why nothing was being recorded.

This isn't the first time that beta testing has caused us to rethink some of our design assumptions. The first iteration of the hardware used a microUSB cable to connect Dr. PD to the host computer. We realized that this was a bit anachronistic, but we figured that using a different plug type would eliminate the risk that users would confuse the ports designed for the devices under test with the host port. The reaction from early testers was universally negative—it seems that everybody really dislikes microUSB—and so we swiftly changed over to USB-C ports for all the connections, which also had the side benefit of reducing the complexity of our BOM.

It goes to show that no decision survives first contact with the end user, no matter how deliberately it was reached!

Dr. PD in the wild

Once the firmware and software started stabilizing, we also sent out a few review units to various bloggers and experts. As a result, we've also started seeing some coverage from the community. IMSAI Guy made a video about Dr. PD a while back, and Dave Jones of EEVBlog reviewed it in a mailbag segment. I greatly admire both these channels, and seeing Dr. PD featured on their videos feels somewhat surreal.

Either way, it's exciting to see Dr. PD reaching more people as we get closer to release, and there are a few more review units out there, so we may see more coverage soon.

Follow along

The testing, bug fixes, and UI improvements are bringing us closer to the final product, and we're looking forward to sharing it with more of you.

If you'd like to explore the project, visit our GitHub page. Once again, all the schematics, firmware, frontend software, and libraries are entirely open source and can be freely accessed there.

We have also published extensive documentation for the project, including an interactive schematic and a full theory of operation that explains how the hardware works.

Of course, if you're interested in getting your very own Dr. PD, take a look at our Crowd Supply page.