On my journey of learning electronics I pretty quickly got interested in circuits related to audio, synthesizer-like circuits in particular. I wish to thank Ray Wilson and his “Weird Sound Generator” for introducing me to the world of synth-DIY.
A friend of mine has a Coron DS-7 drum synthesizer. I found it to be fascinating and I wanted to make something similar.
Pouring over diy-builds in different forums and reading datasheets and looking at various schematics I started gathering some ideas.
The result is a simple linear VCO. It generates a square and triangle wave at one frequency and a ramp at double that frequency. The ramp is achieved by inverting the triangle wave and switching between them using the square wave to control a multiplexing IC. Surprisingly, it works pretty well.
The only exotic (not really) part is the MAX1044 IC I use to generate a -9 voltage to bias the op-amps. Everything else is TL084 quad op-amps, a CD4053 for signal switching and simple, passive components.

Next, to double the square and triangle frequencies to match the ramp, and shape a sine wave.

With all of the materials and tools needed to start fabrication Frederick made his way from the mainland to take part in the construction. Cutting the lumber was made quick using a power miter saw with a 60 tooth finishing blade. Smooth and accurate cuts were made

When the lumber was all cut to size came the marking up of all the pieces for drilling. This was made relatively simple using the 1:1 scale templates available with the plans. At this time the combination square I purchased showed to be an invaluable and versatile tool. Everyone should have one of these in their toolbox.

After lots of careful measuring and scribing by Fred the drilling was made simple with the drill press. Without it the process would have taken at least twice as long and been half as accurate. At the end of the first day we had all of the critical drilling completed. Next morning we quickly drilled and countersunk holes for screwing the frame pieces together.

Considering my limited experience working with power tools the process was pretty pain free. The right tools, two sets of eyes and four hands made great progress on our project.

David Steele’s plans say you can get everything you need at a “Home Center” store. The decision to add certain upgrades from the start included  parts I couldn’t get at the local Home Depot/Home Hardware/Canadian Tire, such as the specialty Acme threaded rod.
With no McMaster-Carr or similar place in Canada I had to do some running around to find all my parts. It turns out that the local branch of Fastenal could get me almost everything I needed, at much lower cost than the regular retail outlets. I was even able to order my Acme threaded rod through them.
The branch arranged for the purchase and importation straight from a manufacturer in Ohio.
I am not sure what their markup was, but after comparing prices I think it was quite marginal and saved me the hassle of shipping it from the US. A week later I picked up a couple of boxes  at the branch and I was set in terms of hardware.
For the frame I decided to use red oak rather than pine studs. Unfortunately I do not have the facilities to finish rough lumber so I had to purchase sanded boards which are very expensive. The price varied from $1.50/ft for 1×2 all the way up to $15/ft for 2×6 lumber.
With a lot of money spent on parts and wood I don’t want to put my crappy Black and Decker hand drill to it so I went and bought a proper 10″ drill press. While looking at different models and prices I found the local Midland Tools to offer both better prices and service.

Learning electronics involves using a so called breadboard, and using a breadboard involves placing and replacing components to test different values. An easy way to do this with resistors is using a resistance decade box.
A resistance decade box is simply a unit with controls for the 1’s, 10’s, 100’s, 1K’s, 10K’s and 100K’s (…and so on) of ohms. This way you can easily dial in a specific value using the controls.

There are plenty of existing solutions for resistance decade boxes, but it has presented me with an excellent opportunity to tackle an important part of hobby electronics: schematic and board layout as well as enclosures.
A fellow noise and sparks enthusiast was very interested in it as well, and we decided to make a few prototypes together and see where it leads.

I started by downloading the  free “Light”edition of Eagle from Cadsoft. From there I started reading the excellent tutorial that SparkFun provides on their site. The whole series is a great learning experience. Make sure to grab their parts library as well. It has proven invaluable to me.

Between the input and the resistor series there is a 1K resistor, so the unit can be used as a voltage divider depending on which jack you use.
Six twelve position switches control the resistance for each “decade”. Position 1 bypasses all the resistance in the series, position 2-10 switches through an increasing series of resistors and finally positions 11 and 12 are “user” out- and inputs where you can plug in anything you want, adding some expandability to the design.

When I felt satisfied with my design, I made “Gerber” files and sent them to the guys at Seeed Studio. These guys offer very cheap PCB fabrication. You are limited in size and amount, but the price can’t be beat.
A couple of weeks later I received my boards back. Having finished soldering one board and checking all the connections I can confirm that it does indeed work as designed. It is a simple design but my first Eagle board, so there could have been a lot of room for mistakes.

Next step will be to make the enclosure for it.

For quite a while I have wanted a CNC machine but I have always thought they were out of reach due to cost. Then I discovered there is a huge DIY-community of people who build their own machines using everything from MDF and wood studs to extruded aluminum and steel channels.

Discussing this with a good friend (Hi Fred!) we decided to build a machine and share in the cost and experience.
Searching for plans to build from, I came upon the Solsylva machine by David Steele. It seemed like a great way to get started and learning what goes into building a machine like this. We decided to go for the 25×25 plans due to my limited space availability.

The plans were $35 shipped to Canada. David shipped the plans the next day after receiving payment through Paypal. About a week later I received a 100+ page spiral bound construction manual detailing every last step in great detail with clear and precise drawings and dimensions.

Since we will likely be modifying the plans a bit and building a cabinet around the machine for dust control I have decided to construct it first using Sketchup. This will give me some initial insight into the construction, as well as hopefully catch size issues. I decided on Sketchup rather than my usual modo because Fred is familiar with it and it has good dimensioning tools.

During this process I will also be making a price/shopping list to make sure everything is within a reasonable budget.