Make an Iron Man Arc Reactor

Step 2 Start with the backplate

The first thing I did was draw up a general plan so I could figure out how everything would fit together. The outer diameter of the Arc Reactor is 4", so if you print the plan photo to that scale it will give you a good guide and help you get everything lined up correctly. All the measurements used in the drawings are in inches and they are really just to be used as a guide- I really just eyeballed everything as I was making it. By no means are they meant to be exact measurements. The most important thing is getting the proportions correct so everything will fit together during the final assembly.

The easiest way I found to cut out all the parts is to draw the patterns on paper and then glue the patterns to my sheet plastic or sheet metal using rubber cement and cut the patterns out with a jeweler's saw. Then file all the edges and smooth them with sandpaper.

So let's start by making the outer ring/backplate assembly. Begin by cutting a 4" diameter disc from PCB material. There are two copper traces cut (or etched) into this as well as a couple of solder pads on the center so you can solder down the LED's. There are 11 LED's- 10 for the clear ring and one for the center lens. The LED's I used are a surface mount type part# NTE 30027. Even though they are a surface mount component they are pretty easy to solder to the copper traces.The LED's sit directly under a clear acrylic ring and they are spaced 36 degrees apart- just make sure they are all facing the same direction! I simply connected the LED copper traces to the center solder pads and then drilled two small holes and soldered some wires from the back of the board to go to my 3v battery.

UPDATE!
Instead of having to make a circuit board and solder all the tiny LEDs you can just get some of these little guys and wire them in parallel-
http://www.sparkfun.com/commerce/product_info.php?products_id=8735

Just glue them down to a back plate and you're good to go!

The outer ring was cut from some thick plastic sheet- I used Delrin because it cuts well and is pretty durable. A good substitute would be 1/2" MDF sheet. I should have painted the ring silver but I ran out of time......maybe I'll make a machined aluminum ring in the future. There are 10 2.5mm allen head bolts evenly spaced at 36 degree intervals around the ring. I just drilled a pilot hole, then drilled a countersink for the bolt head so it would sit just below the surface of the ring. I actually threaded the holes for the bolts but you could probably just shove them in there with a bit of glue.

The outer ring is glued to the PCB backplate with a hot glue gun. Then run a bead of hot glue over the LED's and the copper traces. This will protect the LED's, help diffuse the light and keep the circuit from being shorted out when the remaining parts are installed.

Now you need a lens for the center. I made mine from acrylic sheet, but you could use just about any kind of lens or clear plastic part that would fit. The thing to remember is that if it is too tall then it will come into contact with other parts later on so watch the height. I used a scotchbrite pad on the lens to help diffuse the LED light.

Next an old heart rate monitor strap was glued and screwed to the backside of the backplate. The two screws went through the PCB and into the outer ring, helping to hold everything together.

Comments

[ski bum]

Hi Honus
I am having an extremely hard time cutting my PCB into a 4 inch circle. The PCB keeps on cracking and I can't even remotely get a clean cut. What do you recommend that I use to cut it?
Thank you.

[ski bum]

Ok cool thanks for the advice. I have been using a jig saw with a metal cutting blade on a scrolling feature. I'm assuming that it was to violent for the PCB to handle.

[Honus]

How are you cutting it? I would cut it with a scroll saw or jeweler's saw or coping saw.

[nboyert]

This is a fantastic tutorial! its my next project, and my first go at wiring a circuit board. So this is going to be an adventure for sure :)

I have a basic knowledge of circuits from my physics courses, and roughly get what to do. But part of the wiring layout you have in step two, the second picture confuses me.

The line you have coming down from the middle LED, when it reaches the copper trace it jumps over the inner ring, to make contact with the outer ring.

my question is, how is that achieved when making the cuts?

[Honus]

Glad you like it! The wiring is done on the back side of the board- you can see the wire jumper in the later photos. There are two wires right underneath the chest strap that connect the center LED to the outer LEDs.

[RobertHD]

Great job Honus. I was wondering if you can help me with the round clear ring. I cannot for the life of me find this part anywhere. Or figure out how to make it. I was thinking of getting two different size pieces of PVC piping, and use casting resin and make my own ring. What do you think man? Do you know of a place where i can find this ring?

[Honus]

It is highly unlikely that you will ring a ring somewhere to match the drawing. Your best bet is to either cut it from acrylic sheet using a saw (or laser cutter) or make a pattern from wood and then mold and cast it using clear urethane casting resin (like Alumilite.) You could also make the pattern using PVC pipe or whatever you can find.

[ckhodayeki]

Hey i was just starting on my project and gathering Materials.

the only problem i'm having is choosing some led's can you tell me which one to buy because you've stated three and i don't know which would be the best bet.

Thanks!

[Honus]

I've been using these and they're great-
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110422708960&ssPageName=STRK:MEWAX:IT

[grayseep189]

Whats a good Derlin substitute? Preferably something i can find thicker because Im using 5mm LEDs

[Honus]

You could use MDF or any kind of wood.

[grayseep189]

thanks, i got some wood and some white glossy spray paint im going to use

[grayseep189]

hinking i might buy a stepper motor at my local parts & surplus store then get some white acrylic spray paint and paint it white

[Jrwhar]

Quick question, do you have to use SMD LEDs or can you use regular 3 or 5mm, I'm new to this whole thing any help would be appreciated.

[grayseep189]

you can use 5mm/3mm LEDs this will just mean that you will have to make the backplate thicker because the LEDs wills stick out more.

[grayseep189]

(removed by author or community request)

[Jrwhar]

Thanks this is my first DIY project involving LED's and soldering so i just wanted to make sure. How would you go about making it thicker?

[grayseep189]

I dont think it has to be much thicker, you could achieve this by either getting getting a ticker piece of plastic used for the outer plastic ring or cut another ring and attach it underneath the current one.

[Jrwhar]

Wow sounds good thanks for the help. ^_^

[grayseep189]

no problem, this is also my first DIY so sense i need so much help, thought i might as well help those with questions that i know the answer too

[Honus]

You really need to use SMD LEDs as they are much lower profile. You could use 3mm LEDs but it'll make the reactor quite a bit thicker so you'll have to change some dimensions to make everything fit.

[grayseep189]

yeah i couldnt find SMDs anywhere so I bought some 5mm LEDs, making me also need a larger power supply of 9v

[Honus]

I've bought them on ebay from this supplier:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110422708960&ssPageName=STRK:MEWAX:IT

[bamf91891]

Hey Honus sorry to keep questioning but how exactly do you cut the PCB, I've read how to etch it but can't find how to cut it. Also I saw your update and the lilypads, but I don't quite understand how you would wire them up. As usual, you are the best guy on here for this stuff and thanks in advance!

[Honus]

Just cut the round shape using a jeweler's saw or coping saw. The traces are cut in the copper using a dremel tool. Etching it definitely gives a better finish. You would just wire the Lilypad LEDs in parallel.

[bamf91891]

Thanks a ton, I mean it! I think I'm going to go with the Lilypad LEDs since that would eliminate the need for the hassle of making a board. I'm trying to decide between a dumbed down version of the first arc reactor from IM2, or a more detailed triangular one, so we'll see how it goes but I plan to document them both. I'm also planning on making an instructable of the prototype arm, the skeletal, exposed version and will try to get that up as well if I can get both done in time. Thanks for all your help!

[Honus]

Glad to help- let me know if you have any other questions. The Lilypad LEDs definitely don't have the light output of the larger LEDs but they'll get the job done and it's much easier to do if you're not into making your own PCBs.

[bamf91891]

How much of a brightness loss am i looking at? Also I saw here http://www.instructables.com/id/BUILD-THE-SECOND-GENERATION-ARC-REACTOR/step5/MAKE-THE-CENTER-COMPONENT/ that this guy doesn't use resistors or a PCB on his center, would this be too dangerous? I'm not even sure how to go about just soldering them together like it looks like he did in the sixth pic.

[Honus]

It's maybe a 25% loss- it's tough to say. I got some of the Lilypad LEDs just to play with and I definitely noticed the difference. I made my first reactor without resistors as well but I wouldn't recommend it. Resistors are pretty sensitive to current and I doubt they would last a long time without having a current limiting resistor.

[Jason Amigo]

Great job on the arc reactor, I'm almost done with the prototype (just need to make the LED circuitry), and thanks to your blueprint, it looks almost exactly like the movie reactor (well not as cleanly made as yours) But now I want to make another one, and I want to improve on my previous build. I used cardboard sheet (around as think as a folder) instead of sheet metal for the spider frame and skeleton because I couldn't cut the sheet metal into those precise shapes. How'd you cut the metal cleanly? And also, I'm looking for a substitute for clear plastic, since I can't find any around here. For the first reactor, I just used a glue stick welded together into a circle as the clear ring, but of course it isn't as clear and perfectly circular. Any ideas on how to remedy these two problems? :D Thanks ;) Jason

[Jason Amigo]

I could try the coat hanger thing, but it's risky since I might mar the plastic in the heating process. But it's worth a shot. Thanks! ;)

[Honus]

The best way to cut the sheet metal is to use a nibbler. I used one like this: http://www.amazon.com/Klein-Tools-76011B-Nibbler-Cutt/dp/B0000CBJCT For clear plastic you could glue together several pieces of clear Plexiglas. You could make a mold and pour clear resin to make a ring. What about finding a clear plastic coat hangar and heating it up and shaping it into a ring?

[Jason Amigo]

Wow, Honus, you must put up with a lot to answer all our questions! :))

[Honus]

I figure if you post an instructable then you should be ready to answer all the questions! :)

[acelegna]

hi there.  Final question (I hope :P) It seems that there are 2 ways to make the traces: etch or cut.  You obviously chose cut but i was wondering (from your expierience) what's the difference or Pros and cons between the 2?  Thanx

[Honus]

It really makes no difference regarding function. Cutting it isn't as clean as etching but if you cut it then you don't have to deal with disposing of any nasty chemicals.

[acelegna]

First of all...increible job!!  I was wondering, through your setup (2 AA 1.5v batteries, 11 LEDs in paralel) how long does the power last?

[acelegna]

:O Wow!!.....so 3v is equal to 3000mA? (nooB) :P

[Honus]

No-  3000mAh is the battery capacity. All batteries are different so you have to look for the specs on each battery. Your batteries may have 1700mAh capacity- it just depends on the battery. I was using 3000mAh capacity batteries as an example.

20mA is the current draw of each individual LED so 11 LEDs will draw 220mA. Divide 3000mAh by 220mA and you get roughly 13hrs battery life. Voltage doesn't have anything to do with it.

Make sense?

[acelegna]

Yup...definately.  Thanx a lot.  im in Chile, south America and we don't have as much accesibility to the materials as you do so ill just have to improvise somehow :P  I'll send you a pic when its done