Programming clip for connecting to headers on various PCBs without soldering any pins in place. Great for testing out Arduino modules and for programming microcontroller modules such as STM32 blue/black pills. Potentially quite useful for educational applications, allowing students to connect cheap modules directly to Arduinos or logic analyzers without needing a soldering iron.
It can support pogo pins for 2.54mm, 2.0mm or 1.27mm pitch pin headers, with 1 to 8 pins per clip.
These clips are available from ebay/aliexpress made from laser cut acrylic, but are $20-$30 each, and you typically need to have one with the correct number of pins & pitch for whatever you're programming at the time, so you can easily need a dozen of these for compatibility with everything.
My design is easily printed in two parts, and requires a few M2 bolts (under $10 for a wide assortment of 250+ pieces), a common spring from a 3d printer's bed (linked below for under 10 cents each), and a bunch of appropriately sized pogo pins (linked below for around a dollar for 50). This makes the total cost per clip about $1 including filament, or $2 each including the PCBs.
The PCB includes two different sized boards, one with 5 pins and one with 8 pins. Both have all 3 pin pitches broken out, along with a standard 2.54mm header for connecting wires. The two modules on each PCB can be snapped apart to separate. Any cheap board house should have no problem producing them, I recommend Elecrow or JLCPCB.
For assembly, i recommend first soldering the pin header to one of the PCBs, then bolt both PCBs to the top printed piece. After this you can bolt the two printed pieces together (without inserting the spring) and insert the pogo pins from the bottom. This makes it easier to hold the pogo pins in place and keep them all at the same height, so you can solder the pogo pins into place. They should be soldered on both boards, but be careful to not get any solder on the spring loaded part. Finally you can add the main spring (you may need to separate the two printed pieces to insert the spring, then bolt it back together) and the clip is complete.
2x 12mm M2 bolts
1x 18mm M2 bolt
3x M2 hex nuts
1x 8mm OD, 20mm long spring
1-8x pogo pins (for 2.54mm, 2.0mm or 1.27mm headers)
Links for parts:
Appropriate Nut & Bolt Assortment (Cap Head): https://www.aliexpress.com/item/-/32774934954.html
P75-LM2 Pogo Pins (For 2.54mm headers): http://s.click.aliexpress.com/e/QFTFP1W
3D Printer Bed Spring: http://s.click.aliexpress.com/e/bI91cLDA
EasyEDA PCB Source: https://easyeda.com/Viper-7/pogo_adapter