2018-10-23 (Tu) ModuKey

Version 0.3 of the controller board tried to utilize both I2C ports available on the Teensy-LC. Version 0.4 will rely on the first port and ignore the second. I wired to the second port which was why I could not find anything when scanning because the scanners only look at the first port. An ohmmeter confirmed that I was connected to the wrong port.

Confirming that the wrong I2C port was connected

The data lines were replaced with longer wires and run to some of the spare holes where they were jumpered to the first I2C port. The wires would have been run under the board, but there were already LED wires running under there and crossing them would have necessitated raising the board.

Jumpered data lines

It was possible to scan three of the boards, 1, 2, and 3, but board 0 would not appear in the scan list unless the chip were held tight to the board with finger pressure. This is likely the result of a poor solder joint. A soldering iron and a hot-air reflow station were used to try to fix the solder joint, but they were not successful.

Tools to fix a bad solder joint

The second 1x4 board, identical to the problematic board, was given long lead wires to connect it to the controller to see if it was something to do with the PCB, rather than a bad solder joint. No conclusive results were gained from this experiment.

Second 1x4 soldered to troubleshoot connection issue

ModuKey on GitHub

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5

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