Category Archives: CAD

A status update and playing with Home Assistant

It’s been eight months since I last wrote in this blog. To my regular readers, should I happen to have any, I’m really sorry about that. The main reason for the large gap is I had a full time job and therefore had a massively reduced amount of free time. I say had because it’s no longer the case for… Read more »

Keyboard finished and PCM sound output prototyping

The bring-up of the keyboard controller board was a protracted affair. The first problem was obtaining an RJ10 cable. When drawing up the schematics for the IO board and the keyboard controller board I had naively assumed that the RJ10 cable I had salvaged from an old telephone was wired straight through with pin 1 connected to pin 1 etc…. Read more »

First cuts from the MPCNC

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Working on the MPCNC has been a bit of a background project. It’s hard to believe I started printing the parts for it about four months ago. Here is a little about the MPCNC for some context. The project is the brainchild of “Ryan” at v1engineering.com. It  is a set of 3D printable part designs, given away freely, and other… Read more »

Keyboard debouncing and designing a case

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One critical issue arises when attaching mechanical switches, as found in computer keyboards, to digital electronics: switch bounce. When switches are opened and closed, the connection across the switch contacts does not cleanly transition from its previous state to its new state. Instead the switch contacts will (literally) bounce between the old state and new state before finally, after a… Read more »