Ever since I first saw the tutorial on making 'pogobeds' at SparkFun, I've wanted to build one. (https://www.sparkfun.com/tutorials/138 for those who wish to read up on it)
The biggest problem have always been that I wasn't building multiples of anything - and if I were, the projects was not my own. It wasn't until recently I started making PCBs and producing them at seedStudio. Well, I guess there's a first for everything so the OpenJoust might as well become the first of my projects to have its own programming stand with pogopins.
Apparantly pogopins are quite different. You can get them chisseled, star-shaped and coneshaped. I'd like to think that a lot of other end-options are available but I will leave them. First I got some really pointy ones, which quickly turned out to be the wrong ones. I want some pins with a head on top of them - cone shaped. Oh, and I want them to be big enough to fit the holes in the PCB.
What you then do is to take two blank PCBs (well I needed blank ones because I only needed the programming and power headers to come through. Add a few extra pins for stability and Bob's your uncle.
You can easily see the small cone-shapes on top of the pogo pins. The idea is now to solder the top PCB in the right place (horisontally on all pins). The tricky part is to get both PCBs to align and be straight. if they're not then the bed will also be out of shape and the pins might not align with the device you're programming.
This is where I learned an important lesson:
ALWAYS INCLUDE ALL ICSP PINS!!!!
I thought I could get to the reset pin of the ICSP through the 'FTDI' interface. only problem is that the reset pin is connected through a 100nF series capacitor! when the programmer tries to reset the device the capacitor slows down everything and nothing works. ARGH!
Right now I can live with the task of shorting the pads for the capacitor while programming the bootloader but for buture revisions of the board I'll remember to place either a full header or at least all pins at some location on the board! Phew, I though for a moment that nothing worked. You got me all worried!