Projects and Ideas Currently In the Works...

Just to put some direction to where this blog will be going in the near future, here are some of my current ideas and projects in the making:

- Oldschool Z80 microcomputer.

I took a course at St.Clair College about microprocessors and we had the pleasure of programming some old intel 8085 CPUs. I know it may sound lame to those that are fiddling with the most bleeding edge development boards and whatnot, but to manipulate silicon the way that the first digital electronics engineers did has tremendous value to me. My theory on learning complex things is that the best way to truly understand how something works is do figure it all out for yourself. Sure you can just read some guy's tutorial on how to do X, Y or Z but if you develop the method yourself the knowledge will be extremely concrete. Unfortunately this theory is dying now that I am in University and I see that there is just way too much information out there to develop on your own. Hence; the Z80 computer conundrum.

I decided to start building a 1970's computer in order to truly understand computer architecture. I read and re-read the Z80 CPU datasheet countless times slowly generating a block diagram of how the whole thing would work. Eventually I came up with a design that I was sort-of confident in, so I visited my old friend Digikey.ca, broke out the bread boards and started plugging away.

To my surprise, the design worked on the first go! Besides some almost inevitable quirks in the breadboards which I had to meticulously phase out, I was able to read the state of some dip switches, and copy their states to some D-Latch Output registers that were connected to LEDs. That may not sound like a computer to the uninitiated, but trust me, that simple test circuit displayed the fundamental workings of how you are able to read this right now.

Once I saw my design was functional I wanted to be rid of the god awful breadboards as soon as possible. I typically use EagleCAD to design my PCB's (printed circuit boards) but since I am getting a formal engineering education I decided I might as well learn the industry standard software. Long story short, I got my hands on a copy of Altium Designer and started developing the PCB. The design is complete now but here's the conundrum part:

Am I wasting my time? Today you can buy a $5.00 microcontroller that has everything this Z80 computer will have plus 30 other things and it operates at 10 times (at least) the processing speed . Perhaps my theory on learning the barebone fundamentals is slowing down what I could be learning instead. Due to this internal battle, I have put this project on hold. I will return to it at some point, as I already have all the components, designs and the means to manufacture the circuit in less than a couple hours.

Surrogate Project: 0.75KW 3-Phase Induction Motor Driver using Lead Acid Batteries and Inverter Circuits

My place of employment recently threw out a bunch of old computer parts and junk that was laying around. Included in this pile of gold were some UPS (uninterruptible power supply) units. These basically take the DC voltage from lead acid batteries and put them through inverter circuits to convert the DC to AC and step it up to mains voltage (110VAC in Canada). Being deeply involved with electromechanics practically all the time, I decided to marry the idea of the UPS inverter circuits and a 3phase motor I picked up at an auction a while back. Ultimately I would like to be able to strap my drive circuit and motor on a homemade gokart chassis and zip around using essentially a car battery as the power supply. This project is still in its very early stages, since I'm so busy with school and all, but I already have a very good idea on how it's all going to work. I found this fantastic project document from some students at the Worcester Polytechnic Institute which outlines how sine-wave inverters work in amazing detail. All I really have to do is figure out how to get 3 sine-wave outputs offset 120 degrees from each other with varying frequency. The circuit design shouldn't be too difficult, but I can sense that to get a practically-working-non-exploding model will be difficult. Safety equipment definitely required!

There are a few more things I have going on in the background but this post is getting lengthy enough as it is. Stay tuned in the near future for some more detail on my past projects and the current progression of the ones listed in this post.