Wemos "tripler" base - design flaw "gotcha"

I love Wemos products. I still do despite this discovery. I have been using their "doubler" bases for a while and they make life very easy. As my IOT project expanded towards completion, I needed to connect several sub-assemblies.

To my great joy, Wemos announced the "tripler" and I ordered three from an ebay seller. They are solid and well-made (as I'd expect from Wemos) and are just what I needed.

Well, almost...

I was 90% of the way through soldering header pins to the first when I realised problem no. 1:

The spacing between the 3 layouts is NOT breadboard-friendly! Between 1 and 3 it is, and there is a common GND/5v/3v rail between all three layouts, so it's not a major disaster, but certainly worthy of note. After a little de-soldering and I was soon back on track, till I met problem no 2.

Each of the "boxed" and silkscreened sets of pins are connected. The left-hand side tracks are clearly visible and each right-hand layout has the corresponding tracks in the underside of the board.

EXCEPT ONE PAIR ON ONE OF THEM!!!

The "inner" 5v pin on layout 1 is open-circuit. Every other 5v pin is connected to every other 5v pin, except this one, which is connected to...nothing. You will need to "jumper" it!

And yes, dear friends, that kept me scratching my head for quite a while before I found it. A simple continuity test with the meter confirmed that it wasn't just my failing eyesight...

"Experimentation always beats assumption". Don't bother searching for that quote, I just made it up.

Testbed part 1

Here is the testbed I built to cope with both ESP-01S and Wemos D1 Mini devices.

It has mains input which is fed to a relay board and then on to the actual appliance (usually a lamp) - this is used for final testing, which is all remote (via MQTT) as I don't like going near bare mains wires - and neither should you!

Most of the "bench" testing is done with 12v input from a PSU which is dropped to 5v by an L7805. That's fine for the Wemos D1, as it has an oboard 3.3v LDO, but when I'm testing ESP-01S, it doesn't, so there's a socket to take an external 3.3v LDO (an AMS1117) on a 3-pin breakout board.

The baseboard itself is from a company that doesn't seem to make them anymore, which is a shame as they are solid, rigid and very well-made.

Next comes the Wemos "tripler" base - a lovely piece of kit, but with a serious "gotcha" (see later post)

And then the separate sub-assemblies each of which I will detail in a separate post