Various ramblings – Electronics, radio, old computers, cars & other junk…

Mill Build

Another one of those cool “toys” I thought I would never be able to afford but lusted after all the same. With the availability of cheap stepper motors, driver circuits and free software (LinuxCNC), CNC mills are starting to become quiet affordable for home use.

Of course there are limitations. Just like my lathe this mill is only a baby, limited in its capabilities as far as speed, power and accuracy, there is no fair comparision to “real” CNC mills. But for most tasks that I will be using it for it is more than good enough.

This mill was built from a kit, purchased from Zen Tool Works. They sell pretty much everything you need to get a small CNC mill up and running, are quick to respond to emails and have a very handy Wiki style help area and forum.

PIC Development & Sublime Text 2

While working on a small PIC project as an addition to a larger project (a JUMA RX1 DDS LSB/CW receiver) I had the displeasure of using Microchip’s IDE MPLAB. MPLAB looks like it was designed in the mid-90’s, and while it does let you piece together code and compile it into PIC compatible hex, it’s not the most user friendly program.

While I was battling with MPLAB a friend re-tweeted a link about a new theme for Sublime Text 2, I had a look at the link and the editor looked pretty good! After doing a bit of reading I found out that Sublime Text has the handy ability to call user defined build systems with a hotkey, and as I read on I thought I’d have a crack at getting it working with the XC8 compiler in an attempt to ditch MPLAB.

Linked below is a small project I put together, based very heavily on a set of guides located at Gooligum Electronics. The main requirements to use Sublime to replace MPLAB are a Build System script, and a project specific build file that is launched by the Sublime build system script. This build file specifies various settings (chip type, project name, build options etc…), and is used by the XC8 compiler. – The most basic of programs, one step above a “Hello World” example. A momentary push-button is used to toggle 2 indicator LED’s along with another output pin that will be connected to the PIC chip in a JUMA RX1 radio (to switch between and display which of the two VFO’s is in use). Alongside the source files are the Sublime project files, one for Mac and one for Windows.

XC8.sublime-build – This is a multi platform version of the XC8 build-system file I am using with Sublime Text. This file will need to be loaded into the correct folder depending on your platform…
Mac: /Library/Application Support/Sublime Text 2/Packages/User/
Windows: C:\Users\<username here>\AppData\Roaming\Sublime Text 2\Packages\User\


– The build-system above will need to be tweaked to point at your XC8 install, the project file will need to be pointed at the location of the project. Watch out for back-slashes on Windows, they need to be doubled up (escaped) to be treated as literal in the path.

– You can download the XC8 installer for various platforms here.

– This method can be used to run pretty much anything, you could substitute any build programs/scripts or even flash a microcontroller with this.

Scratch Built Depron F-22 Prop-in-Slot “Jet”

Many years ago I stumbled onto a few websites and YouTube videos showing off scratch-built foamies, and at first it seemed to be a great idea! But after a bit of digging around local parts stores and websites I quickly changed my mind, a very expensive hobby to start off in…

Fast-forward to mid-2012, and I once again stumbled onto some great videos detailing the construction of similar planes, along with some links to parts on an amazing website… HobbyKing!! The prices on all of the parts required to build these planes had come down considerably, it wasn’t long until I had submitted an order for the various parts required to build my very own F-22.

Below are a few of the pictures of the construction and finished F-22. I took the standard plans floating around on the Internet and made a few changes to the design, nothing major, mostly cosmetic changes to make it look a little more realistic. I also followed most of the parts recommendations from the FliteTest video on F-22 foamies here.

Etching boards – Round 1

My first attempts at etching these boards didn’t go so well. Using the toner transfer method has worked very well for me in the past, but it looks like my current printer doesn’t work as well as the one I used previously.

Below are a few pictures of the backplane boards I tried etching, the first photo based off a slightly older design with narrower traces. While the traces were etched fairly accurately, the surface of the traces has some fairly deep pitting where the toner coverage wasn’t thick enough. The worst of the pitting has eaten through to the fiberglass.

In some places the toner didn’t stick down very well, possibly because the board wasn’t clean enough or the toner hadn’t set properly. Ahh well, looks like more testing is needed.

While it is annoying to have wasted two boards worth of PCB material it is good to iron out these problems now. I have gone through all of the boards and increased trace width and also modified some packages to increase the size of pads and decrease drill size which should help with etching. Now I just need to improve the transfer process!

6502 computer project

While I was reading the Steve Jobs biography I was given for Christmas in 2011 I was feeling strangely nostalgic about the good ol’ days. This was strange mainly due to the fact I wasn’t yet born when the Steve’s (Wozniak and Jobs) were designing and building the Apple I & II…

Some time after that I read on Hack-a-Day about a 6502 based computer that Quinn Dunki was working on named Veronica, and instantly knew that I’d love to make something similar.

While not an exact copy of Quinn’s work, the design I have cobbled together does resemble hers quite a bit. My design is primarily based off of Grant Searle’s microUK101 design which itself is based off the UK101, a fairly early kit based machine. Both of those pages have huge amounts of information and are very well worth a read. I certainly read over them a fair few times to get my head around it all!

Just a few quick things, basically a warning to anybody reading this… I’m a “computer guy”, I earn a living working as a computer technician/network engineer. I have no formal training in the field of electronics (as I am very sure many of you will notice), most of this stuff is self taught. Accordingly, things on this page may be horribly wrong. If you do spot anything that is wrong, please let me know!

Building this computer is a way for me to learn more about electronics, mess with some hardware this is older than me for a laugh and have a bit of fun while doing it. If I stuff things up on the way to completion, hopefully I will have learnt something from those mistakes.

The 6502 computer project begins!

After reading over Quinn’s Veronica pages several times I started looking around for more information about various old CPU’s and systems I could base my own off. Very early on I decided on the 6502 as there were so many stable designs using it, and I figured this gave me the best chance of putting together a working computer.

After a fair bit of reading I decided on building Grant’s microUK101 design on a passive backplane borrowed from Quinn’s Veronica design.

After further research and many hours sitting in front of Eagle, the following PCB’s were created. Using the free version of Eagle was a bit of a challenge, the backplane just fits within the board size limitations.