Part 3 - Soldering it

Just the standard diodes pointing downwards and rows to the right. A few pictures as I progressed.

The number one trick i used was to bend a little loop on the diodes to get them to wrap around the pin. I used tweezers to help.

Also bending the diodes 90° before attaching them helps. Make sure diodes black marking is pointing downwards!

Used Cat 5e (ethernet) cable cut up to individual strands as extensions.

Make sure you get "solid core" ethernet cable vs "stranded" ethernet cable. Much easier to work with.

Rows complete.

Columns

Columns done.

Here's the pro micro i got from Ebay. It didn't mark 3.3v or 5v, and I didn't have a multimeter, so I just tested it by plugging it in and flashing it.

Soldering all the little wires straight to the pins. This was hard, and i used tweezers to weight down the cable.

Plugging in a micro usb also helped to weight it.

Routing columns to the pro-micro was difficult due to having to route them under to conserve space. Should have run them first and run the columns/rows later!

Finished all the wiring, plugged in to test. Had to re-solder quite a few joints because it was cold soldered/not enough solder.