2018-09-04 (Tu) Emergency Rotary Keyboard EmerKeyB

Designing a PCB for this project seemed like a logical step. The SS Micro was a convenient size but the cost was high compared to a Pro Micro when pin counts were considered. The Pro Micro was also more widely available. Ideally, the PCB could fit both simultaneously without the need for any code modification. This would make it easier for anyone who wants to copy the project.

Each board's pins were drawn on graph paper in the same proportions as they were on the boards. Comparing the pin locations this way made it easier to determine if there was a way to make a single board capable of interfacing with microcontroller board.

Comparison of each microcontroller's board layout

It would have possible to keep using digital pins 14, 15, and 16 but the board would have been much 10mm longer. Instead, the input pins were switched to use analog pins. A0, A1, and A2 were selected because they were all near the power pins on both microcontroller boards. The code was changed to reflect this and tested successfully.

Code update and proof by typing the analog pin names

With confirmation that the analog pins could be used, a short circuit board was designed to accommodate all the pins and an encoder. Since the microcontroller boards were different widths, there were three columns of pins. The far left column only gets power when used witht the SS Micro board, the center column connects to power and the analog pins of the Pro Micro board, lastly, the far right column connects to the analog pins of the SS Micro board.

There should be no interference from the Power/Ground pins necessary for the SS Micro when this connects to a Pro Micro.

Lower right cluster is pin arrangement of PCB

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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2017-12-16 (Sa)