Starting the next generation Fitbit Cheat-O-Matic, but changing the name, switching to proper high-end bearings, and make a sturdier base and cam follower mechanism. Should be slick if everything fits nicely and plays nicely.
For a luau-themed software launch party at meltmedia, we wanted to be able to play Cornhole. I don't know that Cornhole is a regular game played at traditional luaus, but at meltmedia luaus it is. As I am the Chief Tinkerer (see proof on Instagram) at meltmedia, I volunteered to build the game parts for the festivities. If you're not familiar with Cornhole, it's a very simple game: Toss little corn-feed-filled cloth bags at a 6" hole in 24" x 48" board that's about 30' away from you. For all the official rules, go to (I'm not kidding, here) the Official Cornhole Rules page at the American Cornhole Association website. It's hard not to giggle.
If you have even the most basic of woodworking skills and tools, you can do this.
At the meltmedia office we're making a video podcast once a week. Our design team made a cool backdrop for the little studio area we use. It's a big-ass inkjet direct-print on a full 8' by 4' sheet of foam core. As you can guess, it was a bit floppy and needed some kind of support behind it. It also needed to be lightweight because we wanted to be able to hang it on the whiteboard behind us so we could easily remove it and replace it when we needed the whiteboard. I looked around the garage and all I had that was long enough was an 8' 2x4. So, the entire frame is made from that single pine 2x4. I ripped three 1" strips from it. to get the top, bottom and sides. The sides are just a long piece cut in half.
Well, we've moved into a new and larger space at the office and we sit at these massive wood and steel desks as teams. Our team decided we needed more "flare" at our desk, so, of course, a big-ass warp core was the first thing that popped into our heads. How hard could that be?
The rings of the warp core will be clear-ish fiberglass. The original master, over which we'll make a fiberglass mold for all eight rings, is made of a giant laminated wood block we need to turn on a big lathe.
Turns out, I was wrong about Elmer's Wood Glue: It most certainly does stick heartily to plastic tables. My wife wasn't too thrilled about the weird globs of dried glue on the table, right before a big pool party, so I spent a solid half-hour with a wood chisel scraping off those nasty little glue-scabs. Ick and neat at the same time.
Aside from the general shared engineering tasks, I am in charge of lighting this bad bay. I looked into electroluminescent strips, but it's too expensive and, frankly, not bright enough for our tastes. So, LEDs will be the lighting source of choice on this one. As you can see from the photo above, these inexpensive little 5mm LEDs are plenty bright enough.
The only complaint I have is that they're very directional. At first I thought that I'd just sand them to diffuse the light. But, after some tinkering, I'm going with a sneaky little angled approach: Point the LEDs in a ring at an angle out from the center of the ring so that its light hits the backside of the fiberglass ring in a sorta elongated oval thing. The light from each of the 30 LEDs in a ring will then overlap and make a nice-looking light ring from inside each warp core ring. But, here is my test rig for the LEDs:
The idea with the LED monster above was to see which worked better for diffusing the LED beams better: Point the LED straight out (left LED), or bend it back toward the reflective foil (right LED) which is convex and should spread the light better. Of course, light dies off over distance and the more we bounce it around, the less of an impact it makes. Below is what the LEDs are projecting without blinding the iPhone camera:
So, looking at that photo, you see the reflected LED gets a little black spot on the sun today (Sting) in its beam. The other is brighter, but more concentrated. So, we'll see how my idea of pointing the LEDs at the inside of the fiberglass rings at an angle to lengthen the shape of their beams.
I started out by building the microcontroller and MOSFET circuit, complete with firmware that pulses and fades the LEDs. The speed that the rings pulsate into the middle is set by a potentiometer, at the moment. I think I may add the ability for it to try to pulse to the beat of music. Who knows?
Here is the circuit for the LEDs in action:
The microcontroller is my old favorite, the Atmel AVR. This one is an ATmega328P in the PDIP package. The rings of LEDs (in this video, the lines of LEDs) are powered by 12 volts DC and are controlled by N-channel MOSFETs. Each ring will have a total of 30 LEDs. Each ring will have 10 groups of 3 LEDs plus one resistor all run in parallel on the 12-volt rail. Pretty standard stuff.
Because of the size of the middle section, the matter-antimatter combustion chamber is quite large in our model, we decided to try making a big round thing of foam and then carving that down to the outside shape of the chamber. We'll then (theoretically) cover it in fiberglass and refine the resulting shell after that.
That's it for this update. I'll get more up here as we progress. Thanks as always for following my blog!
EDITOR'S NOTE: I've attached PDF files of the pentagon PCB and the motherboard PCB. If I had time to label them and make them pretty, I would, but this was never designed for mass production or consumption. Use at your own risk and frustration.
For those with a short attention span, I give you a photo of the completed project (my biggest to date):
If you're interested in the story of this things, continue reading...
This idea came about randomly as a gift idea for my wife. I've built useless machines, clocks, etc. for other people (and myself), but hadn't built anything for my wife. I'm not sure what she's going to do with this thing, but it's the thought that counts.
Initially, this was just going to be a small little desktop thing with a few RGB LEDs on a circuit board with some kinda diffuser. Nothing fancy. Then, while walking through Home Depot, I found a frosted glass globe replacement thing for a wall sconce or lamp or something. It looked cool, wasn't too large, and screamed to have a bunch of LEDs stuffed inside it. I was at Home Depot for something else, of course, but I bought the globe, anyway.
Next, I had to figure out how to illuminate the inside of this thing and make it do more than just cycle through colors. The first thing I did was devise a plane for the "bulb." I decided to go with a dodecagon, which I believe means a 12-sided object. Actually, I had no idea what one of these things was called. I just figured that I needed pentagons to make something more globe-like than a cube. I wanted light to emanate outward from this bulb thing like a light bulb, but with as few sides as possible. The sides were no doubt going to be PCBs, so the less complex, the better. Not that this wasn't one of the most complex circuit boards I've ever built in my short time as a hobbyist circuit builder. Here is the paper prototype:
I'm a visual guy, so I wanted to see this thing in real life and also make sure that it would fit into the opening of the frosted glass globe thing I bought. It did fit. I could handle pentagon-shaped circuit boards. The plan seemed doable.
The next step was to plan out and print the pentagon LED panels for the bulb. As always, I use Adobe Illustrator to design the traces on my PCBs. I don't know if I've mentioned this in other posts, but I tend to lay the components for a project on the flatbed scanner and scan them in, then place them in Illustrator so that I have exact placements for through-holes and spacing on my homemade PCBs. So far, that idea has worked out swimmingly. The planning of a PCB in Illustrator looks like these next photos:
After I get the positions of the LED packages on the PCB, I need to connect them together and to ground, which on these panels were the edges, since they'd all be tied together at their corners. In hind sight, I would have gone the route of a common anode, not a common cathode. It would have been easier to control the individual colors with a simple N-channel MOSFET, as we'll see in a little bit.
Like I did on the LED Reading Lamp project (so far, anway), I just worked out the best routes for the traces that would allow the three different colors to be connected in series. Since the red LEDs dropped less voltage than the greens and blues, all six red LEDs were able to be connected in series with a single 1 ohm resistor. The green and blue LEDs dropped enough voltage that I needed to break them up into sections of three LEDs, which meant a total of five series circuits on each panel. My sketch to figure this out looked like this:
When the circuits were all tied together and the microcontroller and all other parts were together, the ammeter showed a maximum draw of only 270 mA. If it were for the 12 volts that drive the panels, I probably could have run this off a USB port. Oh, well. Back to our story... Here is the final trace design, including the location of the limiting resistors on the back side of the PCBs:
The blue resistor outlines show me where I need to place resistors on the back side of the panels. There are also two jumper wires for spanning out the second green and blue series circuits. I did that because I'm lazy and want to simply solder a 5-pin header through the back of the board. I can't fully explain why, at this juncture. It might have been late and I was tired. Who knows?
Finally, I duplicated the pentagon PCB design five more times and laid them all out so that I could print them together and use a band saw to cut them apart. The gap between the edges is enough for a band saw blade with a hair to spare for sanding and clean-up.
As always, I used the toner transfer method to print and etch the boards.
If you count the holes and the pads, I had a lot of soldering to do. A completed panel took me about 15 minutes, if my work area was prepped and the soldering iron was ready.
I don't know how ingenious this was, but after the Iron Man arc reactor thing, I needed a more efficient method of soldering SMD parts. My hands aren't steady enough to not flip the little parts off the board when the tip of the iron approaches. I stumbled onto poster gum at the grocery store and a light bulb went on. A super-tiny little ball of sticky poster hanging gum holds the part in-place perfectly and is non-conducting, so it becomes a permanent part of the board, but who cares? The solder looks 2.4 million times better than if I put a weight on the part or I just carefully attempt to get one leg soldered as an anchor.
Here is what the back side of a panel looks like:
On the back, there is a 5-pin header, a single 1-ohm resistor for the red LEDs, and four 120-ohm resistors for each of the sets of green and blue LED circuits. The original thought behind the header pins was that I'd have lots and lots of time to make really nifty plug-in wires for the various panels and they's all converge on the motherboard of this thing for easy modular construction. That was dumb and painful. So I went the cheap and fast route and soldered wires all over the underside of the complete bulb and had just three wires come out for each color, plus a ground wire. Way easier, although soldering all those little wires was a royal pain.
One of these panels by itself was stupidly bright, so imagine what six were going to do:
With all of the pentagon LED panels built, I had to "stitch" them together by their edges to bring all of their ground lines together. Here is a sort of sequence of the bulb being built:
I used bare copper wire to stitch the corners of the panels together. The extra wire was snipped off, of course.
With all the panels stitched together, I had to connect together the color pins from each of them so that I'd have only one wire for each color coming out of the bottom. But, before I did that, I had to see this thing lit up on the breadboard. So, I created, "Squiddy" the LED bulb:
Lit up, Squiddy looked like this (which was toned down so that the iPhone 4's camera wouldn't freak out):
The bulb is powered with 12 volts, but controlled by pulse-width modulation via the Atmel ATmega168 microcontroller. A potentiometer controls the dimming of the LEDs. The other knob on the breadboard is a rotary encoder. This allows the user to change the mode of the lamp from a plain white for reading to an auto-cycling rainbow of colors to a user-selectable color. The built-in pushbutton changes the mode. The rotary encoder's knob changes the speed of the auto-cycling colors or the user-selected color.
Here is a shot I took with my Canon 20D so that a photo could actually pick up the red, green and blue LEDs in the LED packages on the panels (which turned out to be a really cool artsy photo, to boot):
After all that, it seemed like this wasn't that large of an undertaking. Then I realized I hadn't even designed the motherboard OR the case. So, back to Illustrator to design the ROUND motherboard.
As always and as mentioned above, I scan the parts in and put them in the Illustrator document to be sure I get perfect alignment for everything. Yes, the datasheets have great specs for size and positions of pins and such, but I like seeing the parts next to each other on the screen in front of me. I usually put backside items in faint blue so I know where to put the through-holes to the front. This contraption is designed to run off a wall wart power supply, so it can MAYBE go a low as 12 volts (although my testing shows it prefers more) and as high as about 18 or so. 15 volts seems to be the magic number for many of the orphaned wall warts I have in my box-o-wall-warts. The diameter of the the board is about 5 mm shy of the opening of the frosted glass globe. The four screw holes were meant for stand-offs, but I wound up hot gluing a couple of little boards to the bottom of the PCB like table legs because I was antsy to finish it. Nobody see, nobody knows [click click].
Toner transfer method means laser printing a reverse image of the traces onto shiny blue model decal-like paper and then heating that face down onto super-clean copper PCBs and then soaking in water until the paper lifts off to leave the toner on the copper:
It look AWESOME at this point, because I've started to run the paper and the copper board through the laminator FOUR times. I'm still getting a little pitting in the final etch, but the traces are generally plenty good for my projects. I'm considering trying the photoresist method to see if I can get higher quality edges on my traces.
Etched and drilled, this baby's ready for parts.
An LM7812 12-volt voltage regulator, an LM7805 5-volt voltage regulator, a couple of capacitors, an ATmega168, and an inductor, so far. With the rest of the parts and a few wires to suspend the bulb above the main board, the final main assembly looks like this:
Again, I felt good having completed this much work on the lamp. That good feeling didn't last long when I realized I had no concept for a case or buttons or anything else. Think, think, think... Ding! Into the garage!
Some poplar, a little router action, a pinch of band saw, and BAM! Rough case:
The top piece of wood has a hole with a routed edge that will "grip" the flange on the glass globe. At the back of the lower piece of wood, I've notched out a place for the power plug and the power switch. The knobs were cut off a poplar dowel I had, for what I have no idea. Put together, the rough body of the case looked like this:
The stained/finished gripper groove looks like this:
A test run of the fitting of all the parts and the case:
The knobs were just sitting on the front of the case. The main circuit assembly was kinda hovering in the opening. I had already hot glued the switch and power port into their respective slots. For added stability and wear protection, the power port was super glued, as well.
As for the final shape of the case, I used the band saw to round the corners. The rest was belt sander city. I sanded the ever living crap out of that thing to get all the sides and edges as smooth as possible. I use this 3X 320 grit stuff that really puts a fine finish on the wood prior to staining. The stain is the same stuff I used on the UME Mark II machines (Useless Machine Ever). It's a combination of stain and varnish that makes it really easy to put a nice color and shine on a finished wood product.
The interior of the case was routed out to allow the wires to go from the switches and knobs to the circuits:
The rotary encoder and the potentiometer were hot glued to beat the band. I'm medium-confident that they will not leave their posts.
I cut out a little ring of felt to cushion the glass globe in its hole in the case. I don't know if it was necessary or if it will provide any protection, since we're dealing with a wooden case. Not like it's glass on steel or something. Eh, whatever. Looks swanky.
Next step: Wire up the controls to the main circuitry. I used strips from an IDE cable to keep it neat inside.
As I mentioned before, the main circuit board is standing on wood stilts held in place by hot glue. It's ugly, yes, but it's inside and it's plenty sturdy:
Here is a video of it functioning, albeit a little flaky, but good enough for government work:
I finally finished my own UME Mark II for my own desk for me! Woohoo! My flavor of useless machines ever has a "presidential" look, as some have put it.
This latest model is the first version of the UME Mk II that incorporates a small PCB (printed circuit board) underneath the lid that is attached directly to the pins of the On/Off switch and the two LEDs. It has all the discrete components required to drive the modified servo. It saves time in soldering and it tidies up the wiring under the hood of this magnificent machine.
The wiring that is there comes from the servo, the "parking" switch, and the battery. The next machine I make will have slightly better placement of the board relative to the arm. The clearance was a little tight for my taste, but it still turned out great. This first version of the integrated PCB required some hand-tweaking. I had to cut a couple traces, solder a couple of jumper wires, and notch a little corner out of the board to allow clearance for the parking switch.
The parking switch is the little microswitch inside the box that the arm trips when it retracts back into the box. Its purpose is to cut power on the back swing of the arm. When you flip the On/Off switch to On on the top of the machine, you give power to the circuit and the arm releases the parking switch. When the arm moves the On/Off switch to Off, it actually reverses its own direction. It then heads back into the box until it presses the parking switch, which cuts off power again.
The "3.2" version number is truthful: I revised that silly drawing about 3.2 times. The one above is the latest that incorporates the cuts in the traces I had to make on my machine's PCB. It also takes into account the trimming I did in one corner of the board. In the diagram, I just trimmed the entire edge so that it was still rectangular and easier to cut out.
Everywhere you see black is where there would be copper left on the PCB when etching is completed. The green lines and labels are there for reference but are not printed on the final PCB. The white lettering in the black gets etched out of the copper on the PCB. The little circles at the ends of the traces and a few other places in the black areas are drilled with little bits under my drill press. The final PCB turns out nicely, for a home-brew board, I think.
A car stereo, some extra car stereo speakers, some hardwood, and a ATX power supply for a computer and SHAZAM! You get a garage stereo that can play your iPod, XM radio, CDs, and AM/FM radio. This project was easy and only a little tedious to make. It was fun and it sounds awesome. Plus, the little speakers I had in my garage cabinet are not the greatest, but they're not bad. With a 500 or 600 watt power supply, I can beef it up someday if I get the energy.
I usually put my burning cigars across the top of a ceramic mug on my workbench when I'm in the garage. The great thing about ceramic is that it's pretty much fireproof. What fun is that? The real problem, though, is that the cigars got short enough toward the end of smoking that they wouldn't fit across the mouth of the mug. So, I built an adjustable holder that IS flammable:
Super easy to build. A couple of pieces that sit veritcal, one that is permanently attached at the end of the base. The other has two magnets in the bottom that are attracted to the sets of magnets stuck into the base. As the cigar gets shorter, you simply slide the movable vertical thingie closer to the fixed one.
Magnets are left over from the casino dice Rubik's cubes I made (see posts coming soon).
I had no plans. I just ran some extra pieces of pine through the band saw and drilled some holes for magnets and used Super Glue Gel to hold them in. Nothing to it. Hopefully, the cigar never burns down to the point where the hot end touches the wood on the holder. :)