Lavenderpad Project Diary 1

18 April 2022

So I'm making a completely DIY macropad.

The project is called

LavenderPad written in lavender VCR OSD MONO font

and here is the spec:

4x4 key pad, top row reserved for static functions
Theoretically infinite layers (that is, sets of macros)
Host PC agnostic
Four knobs to control the Windows digital volume mixer via the Deej protocol
Per-key addressable RGB backlighting for maximum possible legibility
2.2 inch TFT screen for at-a-glance information
Massively over-engineered
Cost me a lot of money

And here is the current prototype:

A mess of wires, components and breadboards. There's a keypad, four knobs, a screen, and a few controller boards

It is Not Usable!

I'm doing this write up principally because I am Bored waiting for my paycheck so I can order more supplies and parts from Adafruit.

The knobs, which are currently Dangling connect to the breakout board on the lower half of the breadboard, an Adafruit AW9523 GPIO Expander and LED Driver Breakout. It connects over I2C to the main board, the Adafruit Feather RP2040.

In non-nerd terms, when you turn one of those knobs, the signal has to go through a bunch of slow steps to get to the main board, resulting in lost movement and awful latency.

The next revision of the prototype aims to fix this issue by just making each of the knobs keep track of itself, and having the controller ask for their status whenever a change is made. No shame to the GPIO Expander, it does what it does great, it just doesn't do what I need.

There are also code revisions to be made but they don't really make sense if you haven't read the code, so I'm not gonna detail them. Basically just shuffling things around.

If you're interested, you can follow the project on GitHub in real time, and enjoy my commit notes. Or you can just wait for me to write up my progress here, again.