Who wants to be billionaire-genius-power generator Tony Stark? I do! Since the billionaire and genius parts are a bit out of reach, I figured I could at least make a cool Arc Reactor to wear and pretend.
And since I recently purchased a CNC kit from mydiycnc.com and have been learning to use it, I thought it would be a great tool to help me out.
My goals were to make a relatively thin, wearable reactor that could be backlight with LEDs. And of course to do it on the cheap, since I work for a non-profit and don't make that much money.
So what you need to complete this Instructable (but feel free to substitute with what you have available):
- Some plastic sheets - I picked up some scrap acrylic from a plastic fabrication place, they sell by the pound. If at all possible use cast acrylic vs extruded, since cast will cut without melting much better - I used two thicknesses - 8.5mm (clear) and 2mm (white).
- Plastic Glue - You could use super glue or something else, but a purpose made plastic glue will give you the best bond
- Spray paint - I used black, gold, aluminum
- Copper clad PCB board - to make the light panel for the reactor
- Surface mount LEDs (25) - I used SMD LEDs so I wouldn't have anything poking me in the check on the backside, but using standard LEDs or even LED ribbon that you can get online would be a fine alternative (and that already has resistors built in)
- 27 ohm resistors (5) - To limit current to the LEDs - the value you need make vary depending on the LEDs you use, you can use this handy dandy calculator to figure out what you need: http://led.linear1.org/led.wiz
-Masking tape - for painting the parts
- Magnet wire - I used some that has a clear varnish (so you can see the copper), but you could also use the inner core of some stripped wire
- Other wire - to run to the power supply
- Design plans - I will include the Sketchup files and CNC files (with the .ngc extension for EMC2) for your planning pleasure.
- CNC Machine - I know I know, not many people have these (or even may have access). And every time I saw an Instructable that said "just hop on your CNC/3D printer/laser cutter and do this" I was like 'Yeah right." But since I've gotten one, its what I'm of course going to use. That said, all the parts in this are totally makeable without the machine, using a rotary tool of some sort (likea dremel). A CNC just makes its go easier, quicker, and more accurately.
- Dremel - You'll need some sort of rotary tool to cut the plastic shapes out (if you're not CNCing) and to clean up and modify even if you are.
- Sandpaper - For painting prep (I used some 600 grit)
- Soldering Iron + Solder - For soldering the LED panel and the wire wraps
- Wire Cutter/Stripper
Step 1: Planning
I planned on cutting all the pieces out, then test fitting. After that, paint would be applied, then everything glued together for a final assembly.
For backlighting I wanted to make a PCB with an array of LEDs that would be behind a white plastic panel, so that light would diffuse. First I lit up a single LED to see how the light would diffuse through the white disk, and got about a 2 cm circle of nice light from about a 5mm space from the disk. So I used that 2cm circle in skectchup around a component of the LED (just a box of the correct width and length) to roughly lay down a layout for the LEDs.
From this I drew out the connections to be made (I decided on 5 rows of 5 LEDs based on this: http://led.linear1.org/led.wiz)
Then I drew lines in between all the sections of the PCB so the CNC could separate all the various sections - not the most effective way I know, but I was strapped for time and didn't have the time to figure out how to make a legit one from Eagle
I've attached the Sketchup file for anyone that's interested.
So now I've got all the CNC files I need, time to start fabricating!
Step 2: Fabrication
I used a plugin called SketchUCam for Sketchup to generate CNC cut files. I won't go into specifics here, but you setup parameters such as material thickness, bit size, etch and then can mark cuts on a flat shape of the various pieces. The included Sketchup file has all the cut patterns in it, so if you use a different method to generate CNC files or use different thicknesses of plastic you can use those to make your own.
Using EMC2 (LinuxCNC) and my CNC machine, I used a 1/8 single flute bit (the best for plastic) to cut out all the parts: The clear ring from the 8.5mm sheet, and everything else from the 2mm white acrylic.
After cutting the various pieces, I needed to clean up the 12 U sections that I had cut
I used a sanding drum and my dremel to thin out the slotted ring (I wanted the entire assembly to be as thin as possible) and create a lap joint on the 3 arm inner ring
I also sanded down the 3 soon to be gold rings to thin them out (the thinnest acrylic I had was the 2mm, or else I could have just made a thinner piece)
After shaping and sanding, I used 600 grit sandpaper to run over all the parts to rough them for painting. Then off to the basement to paint! I used gold for the inner 3 ring set, and black for the slotted ring and 3 arm piece. The U shaped I didn't paint until after partial assembly.
Step 3: Assembly
Then I added the first 4 U sections on, space about 1/3" or so from the supports to make a space where I could wrap wire.
I used some tape to hold them down tight to the clear ring while drying.
Next came the rest of the U sections, again holding them on with tape, and after that I cut 4 silvers of plastic by hand to cover the open backside of the supports (that's why I waited to paint, so the paint could cover the joint).
Once those are all glued in place, tape the clear sections off and paint it with the aluminum color. While that's drying, go ahead and assemble the slotted ring and inner 3 arm piece with glue.
With the aluminum painting done, undo all the tape, then begin the least fun part (when you have lots of cuts on your fingers from the dremel) - wire wrapping. I used a piece of electrical tape to wrap around the section and hold down the end of the wire, then began tightly wrapping wire until I had what I was looking for. I used an entire spool of magnet wire for the reactor, so make sure you have enough!
Once you have a section wrapped, sand off the varnish (if its magnet wire) and put a bead of solder down to hold it in place.
Repeat on the other 7 sections!
Lastly, I cut a piece of screen out in a circle to go behind the smallest gold ring, and then glued that down, followed by the other 2 gold rings.
Finished the top off with the slotted ring/3 arm assembly, and clamped and let that set for a bit.
The whole upper assembly is now done, so I glued it to the white circle I had cut for the backlight. (Sorry I forgot to take a pic of this)
Step 4: Electronics
With that done, I fired up the soldering iron and put a dab of solder down for each pad of the SMD LEDs - it helped to print out the sketchup page for reference (since the traces were such big areas)
Then I would make sure I had the LED in correct orientation, and lay it down on the solder pad, then heat one side, then the other. Then add a bit more solder on for good measure, and then test with a 9V battery to ensure everything works. I proceeded to do the rest of the LEDs (it took a while)
Next step was to add the resistors in, which using the calculator I linked earlier I need 5 27 ohm resistors, so I dug those out and soldered them on.
Then I added the power lines, just some regular stranded red and black wire, onto the positive and negative halves of the diskO
Lastly, I attached a scavenged power connector to the end of the power lines, that fit the power supply I already had made from a previous project - basically just 2 9Vs in series running through a potentiometer (heres a link to that project).
After I was done with the board I cut some scrap pieces of plastic to act as standoffs to space the LEDs from the white backlight panel, and glued them to the board then to the backlight. I finished it with some electrical tape around the edge to seal in light and protect any sharp edges.
This finishes the reactor itself, all that is left is to rig it up to wear!
Step 5: Wear It!
I used an old webbing belt that I had to be the main strap for the reactor, and figured I'd need some vertical support to keep it from slipping (since the belt would run under my arms). I eyeballed where to put the reactor so that I could still thread the buckle, and glued 2 lengths of paracord on either side of where the reactor would go.
Then I put the belt on under my arms and ran the paracord over my sholders, and had my wonderful wife mark off where they went in the middle so they were snug. Using those marks I cut the cord and glued it down to the backside of the belt.
That part done, I cut out some heavy duty Velcro to go on the back on the reactor, and on the front of the harness. This way I can remove the reactor for other uses, but still wear it easily.
Everything worked out well, so I put on a black tee, snipped a hole (make sure its a fair bit smaller that the reactor) in the shirt, and stretched it around the reactor. And presto! I'm Tony.