Status 8/3/2020: DONE AT LAST!

I finally received the remaining headers I needed! Just in time too - as I have another Mega2560-based industrial control project that I need to debug.

Here's the finished board:

Note that I have all the little jumpers installed (except GND, not necessary). In this configuration (as shown), all the Arduino-CPU pins (example, a Mega2560) are connected through to whatever shield board is plugged in underneath (example, an ethernet board).

When you need to isolate a particular signal, just take out a jumper!

You COULD also install the jumpers on the bottom of the board, if you prefer to use the top-side for connecting scope/LA probe wires.

Here's the bottom side (where a shield(s) would attach):

You can see on the bottom side that all the headers have tails sufficiently long enough to accept a jumper-plug if you so desire.

Here's a typical stackup of a Mega2560 and a common Arduino-Ethernet board:

And a side view, for completeness:

Status 7/27/2020: Waiting...

Still waiting on some crucial headers to arrive from Mouser. I knew they were made-to-order items... but it's been quite a while now. I recently placed a sample-order at Samtec directly. At some point I really need to find a less expensive alternative supplier for these headers! Any suggestions?

Status 7/4/2020: Partial build...

Most of the Samtec headers arrived (courtesy Mouser). A few are still on back-order (probably built-to-order). However, I have enough parts to make a partial assembly and check the fit... So far, looks great!

Top side (Arduino CPU plugs in on this side):

Bottom side (Arduino shield(s) plug in on this side):

Here's an Arduino Mega-2560 attached:

You can see the 2x10 header there... that's where you install a little jumper across pin-pairs - thus connecting the CPU pins to the SHIELD pins. When you need to diagnose a problem and disconnect a signal - just remove the jumper!

And the bottom side, all I had handy was an Ethernet shield, but you get the idea:

Another view of the whole assembly:

Status 6/28/2020: Ordered parts from Digikey!

So pricey these $amtec headers! I've got to find a less expensive solution (but mechanically identical). For now, I just want to build a couple of boards to prove that everything fits together nicely when stacking together with a Mega-2560 and an appropriate Mega-sized shield board. One of my new industrial-control boards is arriving in a few days - and having this interposer board would really help with debugging (which is why I designed it!).

Status 6/26/2020: Blank PCB fabs arrived!

See below. All I need now are a handful of headers!

Status 6/8/2020: Blank PCB fabs are on order!