I thought about using some industrial strength Velcro to keep everything secure, without that squishy-wobbly feeling that you can get from regular Velcro. Because this Velcro is so strong, I cut it into strips and made sure that the breadboards and Arduino mounts would never have complete contact between the Velcro. This would make it so the pieces could still be moved when needed.
Step 1: Arduino-plex 1.0
I needed a way to shift work to something new, without completely destroying the previous project. I also built this board when I only had 2 Arduinos, and now I will be ordering a 5th board shortly. Clearly, I needed to build a new board.
Step 2: Plexiglass Base
Some of the masking was pealed up around the corners so I repaired it with some blue painter's tape before I started marking and cutting. This piece had a large curve to the top, so I decided to square up the end and get some of the smaller pieces I need from this piece of scrap. I took some of the breadboards and an Arduino and marked my next cut.
I had to lightly sand the cut edges and then I ran a blowtorch down each edge. Once you get the feel for it, you can get a nice, glossy surface by running the flame along the edge. However, If you keep the heat in one place too long, you will bubble the surface.
Step 3: Arduino Mounting
I cut the scrap pieces down for a few mounting bases for my new Arduino boards. I also cut some mounting pads that I could tap threads into and screw some standoffs down into them. For each base, I cut 3 equal sized pads and 1 longer block that I could use to support the USB corner because the screw hole is too close to the female headers. Just like before I ran a blowtorch down the edges to get a nice smooth edge.
I tried a couple different standoffs that I found on Sparkfun and Jameco. The selection has been getting better lately, but originally Sparkfun only had a few aluminum standoffs. These will snap off in the holes you drill and will ruin the piece. Instead, I used these steel standoffs because they are much stronger. You need to make sure you drill the holes wide enough for the threads of the standoff and tap the holes with threads. If the threads are too tight, the screw will bind up in the hole and the head will snap off.
Step 4: Acrylic + Acetone
To line everything up, I screwed the standoffs to the back of the Arduino boards and turned them until I found a nice level spot between the 3 legs. I slid the 4th, taller, unsecured support under the board and made sure there was no wobbling. Then I just squirted a little Acetone next to each leg, and the void is filled by the liquid Acetone, which dissolves the surface of the Acrylic and bonds the 2 pieces together.
Step 5: Breadboard Prep
To prepare the breadboards, I had to slice through the backing tape where the main bus bars connect to the project space. I wanted these to be detachable, to allow for different configurations. The little dovetailed tabs that connect them need a little clearance as well, so I cut the tape back a few more millimeters. I used a utility knife and a framing square to slice straight, even lines through the adhesive backing.
Step 6: Breadboard Mounting
There is a trick to this knife and the package shows how to do it on the diagram. Most of the time, you hold a utility knife at a pretty high angle. With this knife, you want the blade to ride on the plastic like an ice skate blade. Then end of the blade will do the rest as it rides along the plastic cutting it's groove.
I cut most of these pieces a little oversize, so that they will end up the right size after the heat shrinks the edges. The knife and the snapped edges make for a very sharp piece of plastic so I ran a blowtorch over the edges again. I had to take more care with how I held the acrylic because after it got hot it kept trying to warp. Once the edges were melted and cooled, I could see the pieces had shrunk in width just a little, but had grown in thickness just around the edge. This gives the pieces a little more rigidity.
Step 7: Velcro
First I cut off a few pieces of Velcro that were the length of the Acrylic board. For each piece of the loop side that I cut, I cut a matching piece of the hook side so I could stick them together and cut strips at the same time. This Velcro comes 5cm in width, but I wanted it to be about 3/4" wide, so I laid it out and cut it into strips with my straight edge and a utility knife. I then took just the loop sides (the fuzzy side) and laid them out on the Acrylic base to determine the spacing. I peeled off the backing and carefully stuck each strip to make black, horizontal stripes on the surface of the blue plastic.
Because I cut the Velcro in strips, I could run into a problem where the Velcro strips either don't come into contact at all with the piece I am trying to stick down, or come into full contact and make it very hard to remove the piece. My solution was to stick the Velcro hook sides to the breadboards and Arduino mounts on a diagonal. This way, I can rotate any of these pieces in 90° increments and still make contact with about half of the loop side of the Velcro.
To do this I measured the width of the strips, roughly 3/4", and measured down one side 3/4". I lined up my straight edge with the corner and my mark and cut a 45° angle that I then lines up with one edge of the part receiving Velcro.
I chose to put the hook side of the Velcro facing down on the bottom of the various pieces. This way they will stick to a couch or other piece of fabric, rather than sliding off and falling to the floor.
Step 8: Finished Product
In the future I hope someone starts making breadboards that either come with Velcro already on them, or have just a plain plastic backing rather than exposed bus bars. It would make this a lot easier.
This Velcro worked so well, I decided to use it to hold my Arduino board in my tank chassis. This is great because I can take the Arduino stand from the tank chassis and stick it to the work surface. In the future I would like to have a bunch of these boards, all different sizes, that I could quickly put projects together on.
Step 9: Epilog Laser
If I had a laser to cut the individual pieces of acrylic, I would have gotten much cleaner cuts that wouldn't need sanding and heating with a blowtorch.
If you like my project, please give it a vote in the Epilog Laser Contest by clicking the little medal in the top right corner of this page. Thanks!