Category Archives: Electronics

Sean and I just finished building a Raspberry Pi-based handheld emulator system, than can play any classic video games up through the SNES/Genesis era. It came out pretty good, but it took three times to get case printed correctly. The stock case STL files from Adafruit were just not big enough - I had to scale things up in height to get all the components to fit. Eventually I'm hoping to mill (on the CNC machine) a replacement case from some exotic wood, and made some wooden buttons as well. That would look pretty sweet.

I saw a cool idea for a clock on a Kickstarter, and decided to build my own. The idea is that the clock shows the Fibonacci sequence (as high as 5, at least), and you tell the time based on which cells are lit up which colors. The sequence - starting with the smallest cells and increasing from there - goes 1, 1, 2, 3, 5. You figure out the hours by adding up the values of any cells colored green. You figure out the minutes by adding up the values of any cells colored blue and multiplying by 5 (giving the clock a 5-minute resolution). If a cell is colored red, it should be counted in the sums for both hours and minutes. I really like it - it's got a very art deco feel to it.

Two weeks ago Sean begged me to teach him to solder. I had been saying that I would teach him soon, as I felt he was finally old enough. He's been really excited about getting some littlebits for Xmas - and littlebits publishes all their schematics online, so that you can built your own bits to add to any kits you buy from them. That seemed like a really good first project for him, because it only required a few parts but would actually be useful once it was complete - instead of the normal "throwaway" first soldering project most people start with. It came out really good! He's got a very steady hand, surprisingly.

Sean has been really excited about VR all year, and a while ago he tried putting together his own VR headset using his tablet, some 3x magnification reading glasses, foamboard, elastic waistband, and hot glue. He's played around with both VR apps from the Google Play store, and he's tried tethering it to the PC to use as an external display - don't ask me how, as he's figured all of this out on his own! Dang! It works pretty well, so far. He's still got to figure out a good head tracking solution - the tablet's built-in accelerometer only works so-so. And the other problem is the lenses - the focal distance on the reading glasses is just too long to get both eye's images to resolve down to one 3D image. He's got some new lenses coming in the mail tomorrow though, so hopefully you'll soon see v2 here!

Years ago I painted one wall of Sean's room with whiteboard paint. One thing we do every December is count down the days until Christmas on his whiteboard in a unique way. In previous years we've drawn a tree and filled in one ornament per night, or filled in a string of lights in a different color each night - stuff like that. This year we drew a bunch of blank snowman bodies, and finished one per night until Christmas Eve.

This weekend I finished wiring up the CNC machine and was able to get a first test going. The limit switches aren't hooked up yet - I was getting some noise on those lines (they are unshielded, pretty long, and run right near the stepper motor cables), and was getting a lot of "false positive" limit alarms. So I've got to be extra careful until they are fixed - but I couldn't resist trying to make something. Right now I'm really working in 2D - I'm just using the same software workflow I use for the laser engraver. But next weekend I hope to start messing around with some other CAD/CAM software to try something more substantial!

I built a pair of Minecraft block night lights - one for Sean, and one for my nephew Ryan. It's modeled on an ore block, an the colored sections that would determine what type of ore it is are cut out and filled with frosted plexiglass. A set of remote-controlled under-cabinet lights are mounted inside, and all of the different colors can simulate all the types of Minecraft ore. As a nightlight it's a little too bright for sleeping, but the remote has a brightness setting that lets you throttle it down. I got the idea from this site.

I didn't get as far this weekend as I had hoped too - I've got most things wired up, but I still need to make patch cables for the motors and limit switches. The Arduino is programmed and I tested the spindle on/off control by plugging a fan into the relay-controlled outlet. So probably only a couple more hours of work before I can test that each of the axes moves. After that it's just a little axis tuning, and getting my software workflow figured out.

I really intended to post a lot more intermediate steps from the build - but I got caught up in the build itself, and forgot to document it. So in these pics the physical build of the machine is all done - but it still needs the electronics wired up, and will probably need some tuning of the axes. Along the way I also decided to build a whole new stand, which will have an integrated toolbox and shelves and such for holding stock - the stand is structurally complete, but I still need to wrap the sides in some nice birch plywood and trim everything out with hardwood to hide that cheap framing lumber. I had to order a few loose ends tonight before I can start wiring everything - so hopefully it will all come before next weekend so I can get started on the wiring!

Last weekend I added the X-axis rails to the machine, which turned out to not be too bad. Next up is the gantry - which I've already started but don't have pictures of yet.