Wheeliebot: Two-wheeled Robot: A Man Needs to Build

It's true - I think just about every man needs to actually build something every so often. For me, this need was fulfilled today, with the construction of my prototyping assembly.

Today's priority was to 'create a prototyping board'. By this i didn't mean a bit of breadboard, I meant a surface on which to stick multiple breadboards, terminal blocks, and anything else needed - possibly even circuits on stripboard or PCB.

Here, you can see the robot with no prototyping surface - pretty full and not very usable, I think you'd agree:

Wheeliebot Without Prototyping Board

To start with, I needed to consider the Mini-ITX board 'front panel' - with the parallel interface board removed (as I don't need it), I'd need a new unit to control it. My first idea was to create a set of LEDs and buttons on a small bit of stripboard, and wire it to a right-angled header to plug directly into the PC board. However, I found no right-angled headers to I abandoned this idea.

I spoke to one of the lab staff about the need for some sort of solid surface. My first notion was PCB offcuts - these weren't big enough though, and I wanted to use scrap because I love the planet. I'm not actually that bothered, but I never like having to pay for materials that are just going to be used for prototyping. After looking in the workshop at various bits of scrap, we came across a bit of perspex (or some other non-branded PMMA / acrylic). This turned out to be only slightly larger than required, so I wouldn't need to cut it.

After the age and a half I spent scribing the robot's chassis before drilling the PC board mounting holes, I decided to use a drilling template. Using this image, I created an image in inkscape and printed it. After verifying that our department's printers produce nearly perfectly scaled images, I taped it to the perspex and drilled it with a pillar drill. It lined up perfectly with the mounting posts on the PC board. Though I'd originally thought the acrylic looked a bit battered, I was very pleased with the near-pristine result after peeling the manky protective film from both sides!

To allow control of the PC board, I cut the relevant part from the parallel interface board. Cutting PCBs with a hacksaw takes far too long - I advise carborundum wheels - they go much quicker and easier, though they generate far more airborne dust.

After mounting the panel section, I wired the PC board supply lead into the main terminals of the robot, and checked that the system still booted. The final task was to stick some power terminals, breadboard, and wire up a 7805 regulator ready for the following week.

In other news, I ordered 2 AVRs (ATmega1284P), a motor control IC (L298), and a pack of 20 Schottky diodes - so I'll have some more things to play with next week!

Here are a few more images, showing the prototyping board, Mini-ITX 'front panel', airflow path over the PC board, and the power terminal block.