Caution
DUOWEISI makes at least two different tags with a nrf52832 chip.
They are not interchangeable; the programming pad locations are different!
This programmer is for the variant that features the LS2DH accelerometer!
The programmer is split into 3 parts:
The retention-sled is optional; it is used to hold the tag in place for extended programming sessions.
I have arranged all the parts in a single file for ease of printing.
I have also included the CAD model of the actual tag that I used to design the programmer for reference. It's not a perfect model but it's close enough to be useful.
Material choice and settings are not super critical.
You will want to use support material for the base part (green in the image above) but the other two parts should be fine without.
I used PLA with a .6mm nozzle and 0.2mm layer height.
Depending on how tuned your printer is, you may need to use a "reaming" device to clean up the holes for the pogo pins. Any metal rod with a 1.0mm diameter should do nicely.
Tip
Typically, the cheap "sim ejector" tools have a ~1.0mm diameter shaft.
Note
I made a few small improvements to the step files after assembling the programmer pictured here. The initial version works fine but the newer version is a bit better.
Just know that the photos are of a slightly older version of the design and the screenshots are of the latest version.
There's not much to it, really.
Remove the support material and clean up the holes with a reaming tool if needed.
Solder wires onto the pogo pins and insert them into the holes in the base part.
These are the pogo pins I used.
The jig is designed for these pins; the tips of the pins are touching the black surface that the base part is resting on and will just barely make contact with the cap when it is attached to the base.
Important
If the link above ever dies, the pins are listed as P50-J1/P50-B1/P75-B1/P75-E2/P100-E2 Pogo Pins.
Specifically, they have an OD of 0.68mm and a non-compressed length of 16.0mm.
Fill the base with hot glue and attach the bottom-cap part and let it cool and you should have a working programmer jig.
Keep it upside down while the glue cools to so the pogo pins are secured in the correct position.
Important
The Datasheet that I was given did not match the actual layout of the programming pads on the tag so I had to do some trial and error to figure out the correct layout.
| Pin # | Purpose |
|---|---|
| 1 | SWDIO |
| 2 | SWCLK |
| 3 | GND |
| 4 | VCC |
Where Pin # is indicated by the number of detents on the pogo pin holder:
