Theragun Prime USB-C Adapter

Quick disclaimer: While I think this is a very straightforward and safe project, do this at your own risk. Wiring something up always has the risk to damage electronics/cause fires, etc etc.

Most (all?) of Therabody's massage guns now support USB-C charging, but I have an older Prime that still uses a barrel jack. USB-C for everything! 

The Theragun Prime takes in 15V at 1.5A (well, at least that's what their power brick is rated for). As long as your USB-C brick can output 15V, you can use a trigger board and wire it up to a DC jack and take one more step toward the shining future of USB-C.

In addition to the prints, you will need the following components. Please buy the same ones if you want these prints to fit :)

• 1x USB-C 15V trigger board (I used this one, which is sold as a 2 pack)
• 1x 4.8mm x 1.7mm barrel jack (I used this one)

I disassembled the barrel jack and trimmed down the long lead so that it would fit inside the housing. Please take a look at the attached PDF for a walkthrough of the steps! I'll jot em down below as well for ease of reference:

1. Disassemble the barrel jack. You can discard the plastic housing.
2. Trim down the long lead that is wired to the outer barrel. Drill a hole in the shortened tab if you want to make it easier to affix a wire for soldering.
3. Solder short wires between the trigger board and the jack. The Theragun expects center positive on the plug, so + goes to the center lead and - goes to the outer lead.
4. Install the electronics subassembly into one half of housing. It's very important that you get the trigger board nicely docked into the notches that hold it down. It is also important that you get the barrel jack installed correctly (refer to the images).
5. Install the other side of the housing. Again, make sure both the trigger board and the barrel jack are correctly installed.
6. Make sure that the leads of the barrel jack aren't touching. I added some hot glue to this area to stay safe.
7. Optional, you can clean up the ventilation holes in the shell with a 2.5mm drill if you want them to be really clean circles :)
8. Add some superglue to the inside of the shell.
9. Assemble the shell onto the housing!
10. Install the adapter assembly onto the Theragun. I was originally going to use VHB, but I decided to use hot glue instead. I found that it was easiest to clean off the glue squeeze-out while the adapter was clamped in place.
11. Done!

Thanks to this Reddit post which helped me determine that the barrel I needed was a 4.8mm x 1.7mm jack! I think that post is also where I got the link to the USB-C trigger board.

Note: one Reddit post suggests that this little adapter does the trick already, but I didn't love that it would kinda be sticking out weirdly. I have not tried this adapter myself.