Wiring Atari Volcano buttons - question

[EggZilla]

And one more from the goofball.

I have two questions about mounting the volcano buttons:

1. I see no fewer than six poles on the bottom. Can anyone tell me what's what? Two of the poles in the row of four are marked NO (normally open) and two are marked NC (normally closed). Does it matter which I use? And does that make the pair of two in the center the grounds? And if so, where to I run the power?

2. Speaking of power, I've heard these come in several voltages - looking at the text stamped on the side of the button, is it possible that this is a 2 volt button, rather than a 12-volt? If so, how on earth do I run 2 volts in? (If you don't mind, please be detailed here. Circuit design was the reason I changed majors in college.)

Thanks in advance for any help anyone can offer.

-Eric

[SirPoonga]

5v volt with resisters would get you 2v

[OSCAR]

And one more from the goofball.

I have two questions about mounting the volcano buttons:

1. I see no fewer than six poles on the bottom. Can anyone tell me what's what? Two of the poles in the row of four are marked NO (normally open) and two are marked NC (normally closed). Does it matter which I use? And does that make the pair of two in the center the grounds? And if so, where to I run the power?

You should have 5 lugs on the bottom of the switch.  The 3 parallel ones should be labeled NC, NO, and C.  Connect your button input wires to the NO and C lugs (closest together).  The other two lugs are for the LED.  If you connect your LED backwards, all that will happen is that it won't light up.

2. Speaking of power, I've heard these come in several voltages - looking at the text stamped on the side of the button, is it possible that this is a 2 volt button, rather than a 12-volt? If so, how on earth do I run 2 volts in? (If you don't mind, please be detailed here. Circuit design was the reason I changed majors in college.)

You are probably referring to the L2V stamped on the side.  This is part of the Cherry part number, not the voltage.  If I remember correctly, Atari (Cherry) spec on these was +5V with a 330R resistor.


##EDIT##

Ahh, now I see the pic...  I didn't see it the first time??

That is NOT the same Cherry switch I've seen on the Atari buttons before.  In fact, I've never seen that one before.  Disregard my previous comments...

That one almost looks like a double pole?  Use a multimeter to determine which lugs are the switch contacts.  If your multimeter has a diode/continuity setting, you should be able to use that to figure out which lugs are the anode and cathode on the LED.

[EggZilla]

I think I understand. If it helps any, here's a second shot, showing the tines more clearly.

Upon further inspection, it seems I misread the labelling (in my defense, the writing is very tiny). The four poles in a row are actually labelled NO, NC, NC, and C. So that helps a bit. And it seems one of the other two poles is labelled with a + sign, so that must be the 5v connection.

Thanks for your help guys. If anyone's interested, I can post my reactions to how these perform. I got them on eBay, listed as NOS.

Cheers, and thanks for your help!

Eric

[SirPoonga]

I think 5v is too much, butI am not sure.  I thought these LEDs were 3.3V.  Not sure on that.

[OSCAR]

Arcade power supplies, and PC ones for that matter, don't have a 3.3V tap.  The Tempest cp wiring schematic shows the LED's being powered by the +5V line with a series resistor, 330 ohm.

[Frostillicus]

Yeah I got 2 of those newer type buttons, they should be labelled on the little metal tabs and they take 5V.  Use a resistor.   I found they stick up a lot higher than the other older ones.  See that pic in the recent 1UP thread on volcano buttons...

[1UP]

I have a set of these but they're the unlit missile command ones.  Looks exactly the same except without the prongs for the LED (the holes are there, but no LED).  It has two NO and two NC leads, nothing labeled C, COM or GND.

I checked with my multimeter, and it turns out there is no common ground.  If you want a NO connection, you connect your postitive lead to one of the NO tabs, and your GND lead to the other NO tab (doesn't matter which is which).  Same with the NC connections.  Not sure why they did it this way, but that's how it works.  

[EggZilla]

1up is correct - there are two NC and two NO (the one I thought was "C" is labelled NO on its other side - go figure). Thanks a lot 1up, for helping me out with that. You'd think I was blind or something.

As far as the resistor goes, forgive a complete layman's question, but how exactly should I go about wiring the resistor? Can I just attach the wires to each end of a raw resistor, or do I need to mount it on a bit of breadboard and solder it in? Does anyone have a link to VERY rudimentary lessons in this?

Also, can I wire the power to both buttons in parallel, using a single resistor placed in front of the first button, or will I have to run separate 5v lines with resistors to each button?

Thanks again.

[OSCAR]

You can just solder one leg of the resistor directly to the +5V leg on the LED, and then solder the supply voltage wire to the other leg of the resistor.  Every LED still needs it's own resistor, and wire them up in parallel.

[JustMichael]

When soldering to LEDs or other semiconductors try to be quick.  Too much heat can kill them.

[1UP]

You can just solder one leg of the resistor directly to the +5V leg on the LED, and then solder the supply voltage wire to the other leg of the resistor.  Every LED still needs it's own resistor, and wire them up in parallel.

Wait a sec...  You can also wire them in parallel, using only one resistor for the bank of LEDs, as long as the LEDs are all the same type.  The total resistance needed is calculated by adding the current draw of each LED together, as if it were all one big LED.  Am I wrong?  (This is the way I did it on my cab anyway...)

[Carsten Carlos]

You can - though I won't suggest to do so. If the LED's are not from the same productionrun, there is a good chance that they might light up with different brightness then.