Stephen's Weblog

I’m making a concerted effort again to post more often, we’ll see how it goes this time…

First a few quick notes about a few other things I’m working on that will probably see posts in coming weeks:

• I’m nearly done building a Kossel Mini 3D printer. Related, not too long ago I worked with a friend of mine on a simple board to monitor force-sensitive resistors for bed leveling calibration, see his writeup here.
• Caught the bug to build a 2-wheeled balancing robot; I’ve seen too many of these again lately… Only this time I have an electronics platform that can be easily repurposed for this project.

So, exciting times! The Logic Analyzer boards came back from OSHPark all pretty in purple as usual. It’s been a while since I did any serious PCB assembly but I still seem to be pretty good at it :)

This weekend, among other things I’ll be getting started on blinking some LEDs and making sure these boards work the way they should. More on this (and the other reflowed project pictured) later!

Armed with a blinking LED program, I set to work attempting to flesh out the rest of the software for the CNC board. I built and tested a nested vectored interrupt handler, and started trying to port my USB stack from another chip that has very similar USB hardware. As time went on though, the outlook became a bit bleak; A number of things did not appear to be working as intended on this chip, and the manufacturer’s example code included bizzare comments and workarounds for some pretty impactful bugs that weren’t otherwise documented. Not confident that I would be able to make this chip work the way that I wanted, and being less than thrilled with the ease of assembly and some of the design of the CNC Rev1 board, I decided to make a new CNC board.

My design goals would be:

• Ensure the design will work, by using chips I’m familiar with & already have code working on.
• Reduce complexity by only having one motor driving voltage, but still allow that voltage to be changed.
• Reduce the part count per motor, by consolidating components into fewer packages and taking a different design path driving the motors.

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Ah, it’s been a while.

Since I opted to stop posting on a fixed schedule, that seems to have eliminated any hope of regular updates – oh well.

So, I have been largely tied up in a (Very big) project that’s still secret, I’m not saying much about it. But there have been a few bits of progress in other areas – Most notably, I finally got a CNC controller board populated!

Isn’t it lovely?  I certainly think so, after all the work that went into getting this far :)

Sadly, I won’t really get much further at the moment (need to get back to an all-consuming secret project), but this has marked a pretty big milestone in a few of my projects (the reflow controller also works pretty nicely!)

I’ll be sure to take some time and write up these when I make some more progress (or just get sick of working on the more important stuff again)

Progress! At long last!

Over the past month I have been designing a CNC controller for various small projects I’ve been kicking around (oh things like 3d printing, building a pick&place, and some other random thoughts)

Being the hopelessly stubborn sort that I am, I decided to build it from scratch. The design work for something like this is something I enjoy immensely, and while I don’t always get everything right the first time (There are a few inefficiencies, but nothing terrible), it’s been a lot of fun and a good learning experience.

Here’s an image of the final board design, and past the break is a very long thread of text and images showing the steps getting to this point:

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One big thing I’ve been working on lately is bitbox! Bitbox started as just a clever idea, but it was just so interesting that I had to make it :) Bitbox is essentially a tiny music player that will play 8-bit music – sorta like a boombox, but a bit smaller ;)

I still have some software work ahead of me, but here’s the (nearly) final circuit board:

(I say nearly final because I did go on to make some tweaks after taking this image)

Read on for a train of WIP images and more information… (more…)