You know what they say about boys and their toys. While my toys have gotten a little more advanced, I can't help but want to play with my LEGOs every now and then. I've wanted to create a LEGO electronics enclosure for some time and my latest frequency counter project seemed well suited for it.
Working with LEGOs presents some unique problems, namely the fact that they are thicker than normal electronics cases so things have to be mounted a little differently.
Nothing says "Turbo Geek" like encasing your MP3 player, cell phone, or Wii game console (probably my next project) in LEGOs. I'm also considering covering one of my work surfaces in LEGO plates so I can just "stick" test devices like this one to the tabletop. You could build LEGO cases for your whole entertainment center so you can stack devices and lock them together too. The possibilities are endless!
- Top and bottom flat plates. The plates should be at least two rows longer and two rows wider than the electronic component you want to encase (you might want to leave a little more wiggle room, though).
- Enough single width LEGOs to build the walls of your enclosure.
- Super Glue. The jell version is less messy and you'll be less likely to glue your fingers together while handling the LEGOs.
- Various buttons, sockets, indicators, etc needed for your electronics.
- Dremel Tool with high speed drill bit.
- Hand Reamer (See picture 2)
- Tap Set (See Picture 3)
Step 1: Preassembly
This first step in this build is to build the case. It's best to fully assemble the case they way you want it BEFORE applying any glue. In my experience the project almost never turns out the way you expected, so a little prototyping is in order.
As you can see in the first photo, the project I built the case for has an LCD display, so I basically built the case around the display and its circuit board. The gap above the display will be filled in by a block cemented to the top plate since I obviously wouldn't want to glue it to the top of the display.
The walls of the case are made of single width LEGOs built on a flat plate. The plate was larger than I needed so I cut it to size with a hot knife. I left a little more room on the left and right sides because I needed room on either end for switches and connectors, which you will see in later steps.
The other pictures in this series show the process of cutting the plate to size. LEGOs melt very easily. I can't warn you enough, or say this too many times - take your time and cut through the plate a little at a time. If you drag the blade too slowly you'll end up with a warped, twisted, smoking piece of plastic on your workbench. You'll know when you have cut most of the way through when you begin to see a cut line on the bottom of the plate as shown in the fourth picture. At this point you can bend the plate back and forth at the cut a couple of time and it will come apart cleanly. Smooth the cut edge with a piece of sand paper.
Once you are sure everything fits the way you want you can move on to gluing the case together.
Step 2: Gluing the Case Together
Rather than disassembling the case and rebuilding it, I opted to put the top on the box, pull the whole thing off the bottom plate, flip it over and reassemble it one piece at a time. I suppose you could work from the top down too, though I really wanted to avoid accidentally gluing the top on prematurely. I simply pulled the blocks off on at a time and places a dab of super glue on the top of the bottom plate and the nipples on each block before connecting the next block to it. A very small dot of glue on each is all you need.
Take your time and let each row dry for 15 minutes or so before starting the next row. It's easier to build if things aren't moving around on you and if you knock a block out of place it's likely to dry that way and you never get it lined up again.
Step 3: Mounting Push Button Switches
The first thing you will notice when you go to mount a push button switch (or any electronic component really) in a LEGO is that the treads on the component are almost exactly the same depth as the LEGO. So how do you get the nut on the back of the component? I'm sure there are many different options that include countersinking and all kinds of other weird maneuvers, but I opted to leave it off and thread the plastic to hold the components instead.
Begin by drilling pilot holes with a Dremel tool and high speed bit. The Dremel goes through the LEGO easily, where slower drills can crack or break the LEGO. If you don't have a high speed rotary tool then I recommend drilling the holes before assembling the enclosure, just in case the LEGO doesn't survive the process. The holes only need to be big enough to accept the end of the reamer tool, so the bit size doesn't really matter.
Next, ream the hole out until it is just slightly smaller than the component you need to mount. You don't want this hole to be larger than the component because then you won't be able to tighten it, given that you can't get the nut on the back as I said before. Don't panic if you do make the hole too big; super glue or hot glue can save the project in this case.
Choose a tap threader approximately the same size as the threads of your component. If you have a choice of a smaller or larger tap go with the smaller one. It's unlikely you will find exactly the right size tap or the right thread, but that's okay, we want the component to fit tightly and it will cut its own threads as you install it. Don't skip the step of tapping the hole because the component will just spin around at the hole opening if it doesn't have something to grab onto to pull itself into the hole.
Lastly, thread the component into the hole from the back side. I used a medical hemostats to turn the switches shown here. My hands are just too big for the job and the tight fit requires a little bit of torque to get the component threaded into the hole. If you really want to be sure the component never escapes from its mount you might want to put a dab of super glue on the threads too. I didn't, but my components ended up fitting really tightly.
On a side note: I noticed as I was mounting the switches that once they were about half way in the buttons were operable and level with the front of the case, which made them look like flush mount buttons. If you want this effect you can simple put washers on the back side as spacers and just not screw them all the way in.
Step 4: Backside Assembly
The backside assembly is pretty much the same as the front with a few notable differences:
- The hole you see in the first picture was intended for the power connector but it wouldn't fit where I put the hole because I drilled it too close to the side wall. Keep in mind that the last block is THE WALL and not available space on the inside. Luckily, I had a LED indicator light handy that did fit in that space and I can pretend I needed a power indicator. In hindsight the 12 volt LED will make a good fuse for the 12 volt device I built the case for. Burn the LED, save the electronics.
- The BNC RF connectors in this project need to be grounded. Obviously I couldn't put the grounding lugs on the inside because I couldn't secure them with the nut for the connector. No problem - just put the grounding ring on the outside and run a wire through the wall to the proper ground (not shown in these pictures because this instructable is about building the case, not so much wiring up the project).
Step 5: Completed Project
Of course I'm skipping a step here, that of actually wiring everything up. I figured most people on this forum know how to solder and watching me wire the device would be like watching grass grow. So the last step here is to put the top cover on the case. I've chosen not to glue my top cover down for a couple of reasons, mostly so I can work on the device if I need to and because I'd like to eventually find a single plate rather than the patchwork cover I have on it now. The choice is yours though.
Also, notice the white piece above the display that wasn't there in any of the other pictures. This piece is attached to the top cover and comes off when the cover is removed. This allows me to remove the device from the case fairly easily and I didn't have to figure out how to attach it otherwise. I haven't finished the hole around the display at this point, but I'll probably fill it with hot glue once everything else is to my satisfaction.
Mounting the component in the case will be fairly easy as well. I have two choices, either to drill holes in the bottom and mount it with screws, or more likely I will hot glue it into the case. I can always pry the component out of the hot glue if I need to remove it.
It will be interesting to see where others go with this type of case. Please post pictures or instructables of your LEGO enclosures. Personally I'm waiting to see the first LEGO flatscreen T.V.