My electronics are ready to go. Everything except one board is of my design, and I am proud to report that as of today it is all working.
The parallel port board is the only thing I bought. It is a C10 breakout board from CNC4PC. You can find more information on the board here: http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=45.
On the lower left you can see my AE-PWR1 Dual DC Switching regulator converter board. I use this board to convert from 24V to 3.3V and 5V. As it turns out, the C10 requires 5V. But my stepper drivers use an MSP430 microcontroller, so they require 3.3V. The AE-PWR1 worked beautifully to get me the rails I needed. Could I have used conventional linear regulators such as the 7805? Sure! But I had the AE-PWR1 ready to go, so why not? Plus this is way more efficient and will get less hot than the linear counterpart.
At the center left you can see my new AE-PWRPlane. http://www.avayanelectronics.com/Products/AE-PWRPlane/ae-pwrplane.html. This little board allowed me to easily route the 24V from the power supply to the switching regulator and three stepper driver boards. Since it is a dual plane, it also allowed me to route the 3.3V from the switcher output into the three stepper drivers as well as the opto coupler board. I could have used the output terminals on the AE-PWR1. Either would have worked perfectly.
At the top you can see the three stepper drivers. These I have not released into the public yet as I need to validate the design a little bit more. However, they consist of two DRV8828 single H Bridge drivers from TI and an MSP430F1612 microcontroller. The firmware will allow up to 512 microsteps to be generated by using the on board dual DAC channels. This however, is too much resolution even for this project, so I am using way less than that.
The last board is the one I am least proud of as it is an ugly protutype but it works perfectly well and since I do not see myself building more of this, it will have to do. This is a conversion board I needed to place in between the C10 parallel board and the microcontrollers. It consists of a series of optocouplers which I use to convert from 5V to 3.3V. So in essence, they are level shifters. Yes, ideally I should use level shifters but the optocouplers offer the advantage of isolating the stepper drivers from the PC. So if something happens (and I hope it does not), then the PC should be safe.