Aluminium foil - carry voltage? Enough for this?

[Bones]

I have a strange requirement for my cab....

Call me crazy, but check out this picture. it should be reasonably self explanatory.

[Bones]

It here it is switched on. (Fan is spinning, the camera just didn't catch the rotation)

[Bones]

Now I know it works, it's working now. There is no heat in the aluminium foil, no buzzy sparky sounds either.

Is there any reason why this would fail as a permanent method of conducting power within a cab?

Obviously we are only talking 12v here...

[Bones]

And a quick explanation of what I am trying to achieve

[missioncontrol]

 

I think I understand. the fans are on the back panel and you have wires wining to the conections and when the back panels are on they make connection and run.

i guess it would work and with only 12 volts it should be fine. maybe you should run it for several hours just to make sure they dont heat up too much.

[SOAPboy]

So.. can you explain the part where just hooking the fan up to some kind of normal switch is an issue?

Maybe i missed that part..

I mean, its not hard to make a quick clip for the fan, like on a case side for a PC.. and wouldnt be so "unsafe"

[Xiaou2]

 Foil is not very sturdy, and being so thin, in time, may cause it to catch on fire.

 Use a cabinet switch is better  

 But for cheapness, maybe a coke can would at least be better than foil.
Or maybe better , use a couple of large steel washers.

[Bones]

I think I understand. the fans are on the back panel and you have wires wining to the conections and when the back panels are on they make connection and run.

Spot on!

So.. can you explain the part where just hooking the fan up to some kind of normal switch is an issue?

It is not a switch I am trying to create, it is a connection. (I always want the fans to be turned on.)

If the wires going to the fans are plugged into the power supply they have to be unplugged before the panel can be removed. This means unscrewing the panel and while holding it, trying to remove the connection plug. To attach the panel back to the cab the process has to be repeated.

With this system there is no wiring. It is kind of like an electric slot car with the little spring loaded contact points rubbing the track and powering it as it goes.

I just put the panel back onto the cabinet and the power is returned to this panel when the layers of foil make contact.

Or maybe better , use a couple of large steel washers.

Washers were actually my first prototype! Found them difficult to hold down flush once they were wrapped in wire (had to wrap them because I couldn't get solder to stick to them). Coke can would be too thick. I am trying to solve this problem within the raised height of a t-nut which is 2mm. I should also note that to make this thickness the foil needs to be folded about 20 times so it is not one slither of foil that is carrying the 12 volts, it is more like a thick "chunk" of foil.


My test rig has now been running for just over two hours and the foil is still cold with no hot spots, it looks like heat won't be an issue. I also tried setting fire to some foil with a lighter, couldn't get it to burn which is kind of reassuring.

[Bones]

I just altered my test rig and now both fans are connected. This should give me a better idea of how the foil will handle the extra power requirements. (Each fan draws 0.28 amps)

I will let it run overnight and examine it in the morning by unwrapping the foil and looking for any damage, hot spots or discoloration.

[Matt Berry]

It may seem safe at first but as the foil seperates from removal the power is very likely to start arcing between the layers. Once it starts doing that it doesn't take long for it to heat up and cause a fire.

To get the solder to adhere to a washer you have to get the washer hot enough to melt the solder. While this is safer then the foil idea, it still isn't the best idea. Any space could cause arcing and after that you could easily have a fire.

You'd be better of using a real disconnect such as a molex connector, bullet connectors or quick disconnects. You could also just make the wires longer so that you can set the panel off to the side and not worry about it.

[missioncontrol]

o.k. now on Bronco's they use two contact points simalar to the method you are trying to replicate for the rear window defroster to work (the back window rolls down like the side windows so you can open the tailgate.) unfortunaltely mine doesn't have rear window defrosters on it to get a better look at this method.  but you've basicaly got two peices of metal the touch each other upon contact creating the circuit. I know something is out there that is more suitable for your application. I just can't think of where else I've seen them. I'll keep my eyes open today while I'm out and see if I see something.

[quarterback]

Get These

[SOAPboy]

Get These

Was gonna suggest something liek that just now..

You could put the plug in the wood so when its all together, itll plug in, and when you pull it out itll unplug..

Sorry, foil like that isnt safe imo.

[Bones]

Get These

The area I want to mount the connections would not easily allow for these.

I will have a look around today and see if I can find something else. Maybe a couple of thin strips of copper may work...

[MYX]

This seems a little scary to me. Could you perhaps dremmil it down 1/8 of an inch and then get a piece of steel or copper plate and mount it with screws. I guess I don't understand why you wouldn't just put an interupt switch on the door. Door opens and the fans go off. 

[quarterback]

This seems a little scary to me. Could you perhaps dremmil it down 1/8 of an inch and then get a piece of steel or copper plate and mount it with screws. I guess I don't understand why you wouldn't just put an interupt switch on the door. Door opens and the fans go off. 

Because (if I understand correctly) the fans are going to be attached TO the door.  An interrupt switch would still require that wires would go from the door (where the fans are) to the interior of the cabinet (where the power is). 

He's looking for a solution that would allow the door to be removed and without any need to 'unwire' something.

[Bones]

Because (if I understand correctly) the fans are going to be attached TO the door.  An interrupt switch would still require that wires would go from the door (where the fans are) to the interior of the cabinet (where the power is). 

He's looking for a solution that would allow the door to be removed and without any need to 'unwire' something.

You got it.

And today I looked everywhere for a solution. Went to three electronic stores and could find anything, wasted three hours in the process....

*Edit...errr could not find anything. 

[quarterback]

And today I looked everywhere for a solution. Went to three electronic stores and could find anything, wasted three hours in the process....

I think your "strips of copper" is actually a pretty good idea.

[Bones]

I have just decided to extend the cables. It is not my preferred way but.... 

Thanks for the input though guys.

[missioncontrol]

I didn't see anything that would work while I was out and about either.

[Kremmit]

Somebody on here made some home-made jamb tacks a while back- made a whole control panel they could install and un-install just by putting it on and taking it off again.  I'll see if I can dig it up...

edit:  Got it-

http://forum.arcadecontrols.com/index.php?topic=27724.0

Since you just need two contacts, you could probably do something less involved.  Flashlights (is that a "torch" in Austral-English?) just push a spring up against the end of the batteries.. maybe a spring, and a penny. (A penny being the most cheap, worthless coin in the US currency system, insert your local equivalent)

[Bones]

edit:  Got it-
http://forum.arcadecontrols.com/index.php?topic=27724.0

Since you just need two contacts, you could probably do something less involved.  Flashlights (is that a "torch" in Austral-English?) just push a spring up against the end of the batteries.. maybe a spring, and a penny. (A penny being the most cheap, worthless coin in the US currency system, insert your local equivalent)

Yeah that is along the lines of something I tried today with a screw and a solder tag. It worked but I was getting point contact.

Well it's all wired now anyway, just went with the longer cords as Matt Berry suggested. I am definitely gunna keep my eyes open in the future for something suitable.....If I ever find it I will post it here.

[mccoy178]

What about something like this on either side:



I found it here:
http://www.stanleyhardware.com/default.asp?TYPE=CATEGORY&CATEGORY=HDW+CABINET+CATCHES+AND+LATCHES

[RayB]

They also make quick disconnects that are "male" and fit in to the usualy "female" ones.

[MaximRecoil]

What about something like this on either side:



I found it here:
http://www.stanleyhardware.com/default.asp?TYPE=CATEGORY&CATEGORY=HDW+CABINET+CATCHES+AND+LATCHES

I was thinking the same thing. The screws used to mount the two parts of that latch would double as screw terminals for the wires too. And in yet another case of doubling, those latches, if mounted near the middle of the back door on both sides, would also give additional support to the door in that area, a place where many original arcade machine's back doors tended to bow out with age, since they were supported from the top and bottom, but not in the middle.

[Necro]

You prob. already know this, but they sell 'dippable' latex stuff at the hardware store.  You could insulate these things (above) or whatever you use where the contact is unneeded with the rubber/latex dip by either painting it on or just carefully dipping the item.

Just for safety.

[quarterback]

You prob. already know this, but they sell 'dippable' latex stuff at the hardware store.  You could insulate these things (above) or whatever you use where the contact is unneeded with the rubber/latex dip by either painting it on or just carefully dipping the item.

Just for safety.

Good idea, Necro.  I was thinking "wrap in electrical tape", but your idea's a little more slick.

[Kremmit]

You prob. already know this, but they sell 'dippable' latex stuff at the hardware store.  You could insulate these things (above) or whatever you use where the contact is unneeded with the rubber/latex dip by either painting it on or just carefully dipping the item.

Just for safety.

"Dip-able Latex":

[Crowquill]

When I started reading this I was thinking pretty much the same thing as Kremmit. A spring and metal plate should work pretty well. It's similar to the springs and plates in a battery compartment.

I started trying to work it out before I got to the end of the posts, so I ended up making a diagram before getting to the part about just using the longer wire. Oh well...maybe it'll help somebody...

The fans would be daisychained together leading to a metal plate and spring on the other side wired to common.

[Bones]

Well that looks like it is definitely on the right track....

[Crowquill]

Probably more like this:

[Lilwolf]

Boy, the pictures of my tac switches I posted are SO old.   I never started selling them because I couldn't find a perminent source of springs needed (for something other then a few bucks each... making them not worth it at all). 

But I run 5v through one of my tac switches and it works well. 

What you will really want to watch out for is making sure that there is some give.  The springs -> metal should be perfect!  I would go that route if I where you. 

I also wounldn't go tinfoil because I see it working great for a few weeks... and breaking as soon as you want to stop thinking about it.

[Stingray]

Crowquill's diagram looks perfectly workable to me.

-S

[MinerAl]

Tear apart a pair of cheap flashlights to get those springs.  AAs for little ones, Cs or Ds for big ones.  Wait, now it sounds like I'm talking about something else...

[Havok]

Tear apart a pair of cheap flashlights to get those springs.

[Ed_McCarron]

Since it went that way, and you need something metallic and spring loaded...



Someone had to see that coming.