Iron Man Arc reactor *Need Help*

Hey everybody, I'm trying to build an arc reactor for a display for our 'movie room'. I'm going to use the "Iron Man Arc Reactor" toy as the base for modifications to begin. I've got 5 white LEDs, 5-68ohm resistors and a tiny switch to start. Anybody have any ideas of how to configure it? Any pics?

This is gonna be my first really in depth build. I want it to be powered by a 9v and be on constant power w/ the flip of a switch.

-Thanks in advance guys/gals
I'll post pics as soon as progress really begins.

"in depth" and you're using the toy as the base? i would just make the whole thing out of scratch like in the countless youtube videos of people doing exactly what you're asking about :P as for the science of resisters to 9v, thats not my department

I recommend this site for helping you out with basic LED circuit building. I could explain all the rules of circuits, but the information is easy enough to find. This site is a tool to do the math for you.

Current limiting Resistor calculator for leds

The big question you need to answer still is what the current limit and voltage drop is for your specific LEDs. Look up those specs, then the rest is easy. You probably will have to get different resistors, generally you pick those based on ratings that fit the specific design of your circuit.

CaptainMorgan said:

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I recommend this site for helping you out with basic LED circuit building. I could explain all the rules of circuits, but the information is easy enough to find. This site is a tool to do the math for you.

Current limiting Resistor calculator for leds

The big question you need to answer still is what the current limit and voltage drop is for your specific LEDs. Look up those specs, then the rest is easy. You probably will have to get different resistors, generally you pick those based on ratings that fit the specific design of your circuit.

I picked up the 68ohm resistors based on what i was building so I shouldn't have to buy anything else really. Thanks for the heads up on the website though I couldn't find anything like it and searched for a few hours.

DizzyStrmtroopr said:

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"in depth" and you're using the toy as the base? i would just make the whole thing out of scratch like in the countless youtube videos of people doing exactly what you're asking about :P as for the science of resisters to 9v, thats not my department

Yes, "in depth" meaning I'm tearing something completely apart and trying this. Hence the phrase. I don't have the time or the tools to make it from scratch. I'd love to but just can't do it.

McFly88 said:

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I picked up the 68ohm resistors based on what i was building so I shouldn't have to buy anything else really. Thanks for the heads up on the website though I couldn't find anything like it and searched for a few hours.

Hmm, you should definitely post the specs for your LEDs. A 68ohm resistor for each LED would mean running around 85 milliamps through each LED. That is really high for a typical LED, so unless you have some higher powered ones that you bought I'd be surprised if it's right.

McFly88 said:

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I don't have the time or the tools to make it from scratch. I'd love to but just can't do it.

xrobots built one out of dollar store items.. its easier than you think and can be done in a day with all the materials, but i digress. cant wait to see the finished product!

I hope its not the 2012 Toy as the cover plate is depressed in which makes everything cramped in there.

Anyway, this is my Iron Man I toy version: http://chowfookcheong.com/IM%20II%20.../Arc%20001.htm

I sincerely hope you're not buying two...

DizzyStrmtroopr said:

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xrobots built one out of dollar store items.. its easier than you think and can be done in a day with all the materials, but i digress. cant wait to see the finished product!

That's not too bad to do it out of dollar store parts. I found a few here and there.

CaptainMorgan said:

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Hmm, you should definitely post the specs for your LEDs. A 68ohm resistor for each LED would mean running around 85 milliamps through each LED. That is really high for a typical LED, so unless you have some higher powered ones that you bought I'd be surprised if it's right.

I asked a buddy whom is great with electrical components with a 3.3V LED found at radio shack. 5 LEDs and 5 68ohm resistors are being powered by a 9 volt battery.

Mr.Engineer said:

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I hope its not the 2012 Toy as the cover plate is depressed in which makes everything cramped in there.

Anyway, this is my Iron Man I toy version: http://chowfookcheong.com/IM%20II%20.../Arc%20001.htm

I sincerely hope you're not buying two...

I actually used the "Avengers" Arc Reactor. It's not the one with the triangle piece in it. It has a single red circle right in the center on the clear plastic. I'll have pics up soon to show.

Here is a picture comparison. The Left is from the first iron man movie, which I have successfully modified. I bought the one on the right in March and I have to think on how to achieve the affect on the left. Both toys are the same from every angle except that the Avengers has more sound. What is not 'nice' about the Avengers version is that the blue plastic is now 'caved in' so making the white LED ring is going to need more thinking.

I think that is the reason why I stopped exploring this but I might get up to steam again after my Wiper electronics are out.

McFly88 said:

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I asked a buddy whom is great with electrical components with a 3.3V LED found at radio shack. 5 LEDs and 5 68ohm resistors are being powered by a 9 volt battery.

The voltage drop across the LED isn't that important here. It just means you couldn't have more than two in a series (3 would hit 9.9V), but if you're wiring them all in parallel like it sounds the voltage is only one part of the math.

LEDs are current limited devices. You need to find out the maximum current they can handle to determine LED values. A typical LED is around 20 milliamps. That would mean to wire it your way you need 5 330 ohm resistors.

OK. Let's see.....

The 5 White LEDs I buy here have a average forward voltage between 3.0~3.5 volts and their forward current is usually 25mA.

So, if you were to wire them in a parallel configuration and using 9 volts, the resistors you need would be 270 Ohms and 1/2watt versions. (I am assiming the LEDs used were 3.3 volts, 25mA). This is the parallel configuration where each LED has their own current limiting resistor.

For the 68 Ohms to work, using the 3.3 volts, 25mA, the voltage required would be 5 volts, again on the assumption that each White LED has their own current limiting resistor.

9 volts is very high, IMHO. Most of the power lost in the 9 volts would be in the form of heat dissipation through the resistors. Have you tried getting your friend to ustilise the toy's 3 volts batteries instead? This would also eliminate the problem of where to hide the 9 volt battery.

Mr.Engineer said:

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Here is a picture comparison.

Yeah i have the "Avengers" reactor on the Right. I'm still trying to figure out how to configure the lights within it, along with the 9v battery. HaHa

Stealth has a three part tutorial on how to build an arc reactor for cheap on YouTube under theherotutorials.

Mr.Engineer said:

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OK. Let's see.....

The 5 White LEDs I buy here have a average forward voltage between 3.0~3.5 volts and their forward current is usually 25mA.

So, if you were to wire them in a parallel configuration and using 9 volts, the resistors you need would be 270 Ohms and 1/2watt versions. (I am assiming the LEDs used were 3.3 volts, 25mA). This is the parallel configuration where each LED has their own current limiting resistor.

For the 68 Ohms to work, using the 3.3 volts, 25mA, the voltage required would be 5 volts, again on the assumption that each White LED has their own current limiting resistor.

9 volts is very high, IMHO. Most of the power lost in the 9 volts would be in the form of heat dissipation through the resistors. Have you tried getting your friend to ustilise the toy's 3 volts batteries instead? This would also eliminate the problem of where to hide the 9 volt battery.

If you're going to put all the LEDs in parallel then yes 9V is a waste. In general wiring LEDs in series up to the voltage available, and then the series circuits in parallel with each other is more efficient. It just takes a slightly better understanding of circuits.

In my arc reactor I use a 12V battery pack that I keep externally so that I can keep it powered for a full 12 hour plus day of Con, and run sets of 3 3.5V (4V max) LEDs in series. I also run 20 LEDs in mine as well to make it extremely bright.

I have a 110v to 9v transformer I parted from a pair of external computer speakers. You could convert the battery input to wall outlet powered if you get tired of changing out batteries, or want to plug the reactor into the wall to turn on via light switch.

DizzyStrmtroopr said:

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I have a 110v to 9v transformer I parted from a pair of external computer speakers. You could convert the battery input to wall outlet powered if you get tired of changing out batteries, or want to plug the reactor into the wall to turn on via light switch.

I have a bench power supply for testing car electronics that I've used to do the same thing for when I'm not wearing the ARC reactor.

DizzyStrmtroopr said:

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xrobots built one out of dollar store items.. its easier than you think and can be done in a day with all the materials, but i digress. cant wait to see the finished product!

I think you'll find as he lives just down the road from me that it would be £££ Pound store parts. I 3d printed mine from a cad file but used his light idea as it was cheap and easy

Paul