Failure Analysis - Not thinking through connector locations

Failure happens from time to time when building projects or creating things.  I'm lucky that most of my mistakes are fixable after the fact or that the cost is negligible.

I have a 10 year old project I wanted to update.  It is a stack of three boards.

  1. The bottom board is an Arduino Ethernet
  2. The middle board is a spacer that raises the third board above the ethernet connector.  The middle board has been cut to avoid touching the Ethernet connector
  3. The top board a NeoPixel 8x5 LED array
I wanted to add a Nokia 5110 LCD to the board to show status and configuration.

This Arduino Ethernet board has some stuff going on.  The left side of the board looks like it is the side that we would expose through a bulkhead panel.  The right-hand side has a programmer connector. I made that a 90-degree right-angle connector so that I could plugin in a serial-to-USB adapter while a shield was stacked on top.

The thing is to remember that the left-hand side is going to be mounted so that it is reachable from outside the case.

I added a prototyping shield to the top of the Arduino Ethernet board.  I cut a notch in the prototyping board where the big Ethernet connector is so that the board could lay flat on top of the Arduino. I didn't want to lose any stacked connectors because we have a 3rd layer coming.  But it looks the upper left corner probably could have been neater.  The little fragment labeled "reset" was probably retained for a button but I doubt it works the way it was cut.

This was the first minor fail.

I added a header for an LCD display in the bottom left.  There is a NeoPixel panel going on top of this protoboard.  That means the pins can't stand upright.  I mounted them on the left, next to the edge. The thing works great. 

Then I realized that the LCD pins stick out too far past the other connectors.  They are in the wrong spot for a cable connection. 

They really aren't in the right spot to solder the LCD board directly to them.  I had intended to mount the LCD on a different edge and now we'd be locked into mounting the LCD at that location.  

Hacking it Up

We could remove the connector or leave the connector but remove the jumper wires and start over with a new connector.  I didn't want to do any of that because I was afraid of destroying a pin. Some days my soldering skills aren't great.  I could have cut the connector off and then pulled the pins 1 by 1.

The final decision was to
Bend the connector 180 degees  so it would be facing the other way.

You can see in the picture that the cable now runs the length of the protoboard.  This means the LCD can be used anywhere without impacting the physical design.


This could have gone badly. The connector pins could have broken.  The solder connections could have ripped the connector pins out of the board. I've had plenty rendered unusable after this type of fix.


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