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Author Topic: Reproduction Atari Volcano Switch Voltage  (Read 1742 times)

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Drakkorcia

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Reproduction Atari Volcano Switch Voltage
« on: January 23, 2022, 03:55:00 pm »
I have a couple reproduction volcano button switches from Arcadeshop It has a 6.8K resistor and has 5A 250V printed on the switch. I originally used these with my zero delays and plugged them into the 5V power slot and they worked perfectly. But now I use a 12V molex LED chain for my LED buttons. I want to know if I plug this switch into my 12V chain, will it blow the LED? Seems like it should work if all the other button LED's do.

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #1 on: January 23, 2022, 11:46:16 pm »
5A 250V printed on the switch.
That is the rating for the switch, not for the LED.

They are in the same physical assembly, but are not electrically connected to each other.



It has a 6.8K resistor
That is a much higher value than expected for 5VDC or 12VDC power.

Only application I can picture that would use that large of a resistor is if you're using 120VAC to power the LED.   :lol

I want to know if I plug this switch into my 12V chain, will it blow the LED? Seems like it should work if all the other button LED's do.
12v will blow that LED unless you use the right size current limiting resistor.

What you don't see about the other button LEDs is that there is a current limiting resistor hidden in the LED holder.



Javeryh used these volcano switches in his build here.
So anyone have any idea how to wire the volcano buttons?  I got them from Arcade Shop. 

You'll find lots of useful  info in that thread.
- The one change is that instead of using 5v to power the LED, you plan to use 12v so you'll need a much larger current limiting resistor than the 220 ohm that he used.
- Javery's setup dropped 2v across the LED and 3v across the current limiting resistor -- 5v total.
- Your setup will need to drop 2v across the LED and 10v across the current limiting resistor -- 12v total.

Running these numbers through an LED calculator, returns a current limiting resistor value of 510 ohms, 1/4W.
- Power supply voltage = 12v
- LED voltage drop = 2v (found in Javery's thread)
- LED current rating = 20mA
- Number of LEDs = 1
https://ledcalculator.net/#p=12&v=2&c=20&n=1&o=w
- Note: You'll need a 5% (or better) tolerance resistor because 10% and 20% don't come in this value.
https://www3.nd.edu/~jott/Measurements/Sensors/Standard_Resistor_Values.pdf

If you reduce the LED current rating to 15mA, you get a 680 ohm, 1/4W resistor.
- This will be almost as bright, and should extend the life of the LED.
- The current limiting resistor will also have less wattage to dissipate (153mW vs. 204mW) so it will be cooler.

- Note: 680 ohm resistors are available in all tolerances.


Scott

Drakkorcia

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #2 on: January 24, 2022, 12:16:00 pm »
Scott,

Thank you for the detailed and thorough assistance. I just realized I have an i-pac 2 which has 5v pins on it. The only problem is I have never used header pins before so I have no idea what kind of connector I need to crimp on the + wire so I can attach it. I don't want to solder. I also assume for the ground you would just use either the P1 or P2 ground slots, right? I understand it has been recommended to put a resistor on the wire too but I hooked these buttons to 5v on my zero delay with no trouble at all. But if it is really necessary I'll give it a shot. Never installed a resistor before...
« Last Edit: January 24, 2022, 12:18:01 pm by Drakkorcia »

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #3 on: January 24, 2022, 03:50:27 pm »
The only problem is I have never used header pins before so I have no idea what kind of connector I need to crimp on the + wire so I can attach it.
They are commonly referred to as Dupont pins.

They can be a bit tricky to crimp properly, but you can avoid that by using pre-crimped wires or jumpers.



I don't want to solder.
Then Euro-style terminal strips are your friend.   ;D



I also assume for the ground you would just use either the P1 or P2 ground slots, right?
Correct.

That's how Javery did it for his build here.
- He asked the same type of questions that you're asking.  That's why I included the link to his thread earlier.   ;)
- If you're using 5v to power the LED, use a 220 ohm resistor.
- A 1/4 W or 1/8 W resistor is more than large enough -- 1/2 W as recommended in this image is a bit of overkill.



I understand it has been recommended to put a resistor on the wire too but I hooked these buttons to 5v on my zero delay with no trouble at all. But if it is really necessary I'll give it a shot. Never installed a resistor before...
I'm really surprised that the LEDs didn't fry when you hooked them to 5v on your ZD.
- Maybe there is some sort of current-limiting circuit in the ZD that protected the LEDs.   :dunno

You need to limit the current to around 15 to 20mA for most LEDs or they'll blow like a fuse -- that's why a current-limiting resistor is your friend.


Scott

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #4 on: January 24, 2022, 07:52:42 pm »
It would help if there was actually some documentation on these repro's. Maybe the LED on it can handle 5 volts? Maybe I just got lucky? In any case a resistor should be very cheap and could easily be soldered and shrink wrapped inline and there would be no doubt.

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #5 on: January 24, 2022, 08:57:15 pm »
Scott,

I found some dupont wires but they are too short to reach my i-pac and its headers so it will be better to use my 12v chain. Instead, I'm opting for a 1/4 resistor pack on Amazon with 60 levels of resistance. Would this be a good pack, and which ohm level would you use for that 12v? There is also a YouTube video of someone putting these into his A1UP by tapping into his 12v with a 220 ohm resistor without issue. If you give the okay, I'll get the pack.

https://www.amazon.com/gp/product/B08PF3HNMD/ref=ewc_pr_img_1?smid=A14FP9XIRL6C1F&psc=1


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Re: Reproduction Atari Volcano Switch Voltage
« Reply #6 on: January 24, 2022, 11:16:39 pm »
It would help if there was actually some documentation on these repro's. Maybe the LED on it can handle 5 volts?
Agreed, but we can (somewhat) reverse engineer the specs with this simple test.   :cheers:

Best way to tell for sure is to use your multimeter in series to test how many miliAmps are flowing through the circuit below  while the LED is forward biased/lit.
- Use one LED and one resistor as shown so there's no fancy serial/parallel circuit math and it's also a best practice to use a separate resistor for each LED and in this case it will keep you from exceeding the wattage and burning up a 1/4 W resistor like the ones you're getting.   :scared
- With a 2v LED and a 680 ohm resistor, you should get something close to 15 mA.
- With a 2v LED and a 510 ohm resistor, you should get something close to 20 mA.

12v ---- current limiting resistor ---- + LED - ---- red lead--multimeter--black lead ---- ground

If your readings are much lower (i.e. 2 or 3 mA), there's likely a current limiting resistor hidden inside the volcano button assembly.  Post the results of both tests and I'll try to (somewhat) reverse engineer it.

I'm opting for a 1/4 resistor pack on Amazon with 60 levels of resistance. Would this be a good pack, and which ohm level would you use for that 12v?
That would be a fine assortment.   :cheers:
- The 680 ohm should be extremely safe. (15mA)
- The 560 ohm should be very safe.
- The 510 ohm should be safe. (20mA)

There is also a YouTube video of someone putting these into his A1UP by tapping into his 12v with a 220 ohm resistor without issue.
I'll take my 40+ years of experience working and playing to component level with electronics over the word of some YouTube rando that managed to get the LEDs to last long enough to shoot a video.
- I don't want to pick on him, but it's clear that if he is knowledgable about electronics he isn't clearly conveying that info and isn't following best practices.  Caveat emptor.

The measurements from the inline amperage test mentioned above will provide valuable insight into what you're actually dealing with.

Unless there is a current limiting resistor hidden inside the volcano button or the LED specs are way outside the usual range for red LEDs, the video results do not make sense.

There's probably some unidentified variable in the equation because it's called Ohm's Law, not Ohm's Suggestion.   :lol


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Re: Reproduction Atari Volcano Switch Voltage
« Reply #7 on: January 24, 2022, 11:43:35 pm »
Thank you sir. The youtuber was just to point out someone put too small a resistor on and was probably lucky. I wanted to confirm with you. Obviously I trust you and your experience which is why I opted for the pack so there would be more powerful resisters to choose from. These repro's aren't like some 50cent lamp you can experiment with and be wrong; they cost $15.95 and are currently unavailable. So I want to get it right.

That's why I made this thread because I was getting ready to plug it into a 12V chain until I decided to ask someone who knows what they're doing. Good thing I did. On Amazon they like to sell resistors in 100pcs packs which would be a waste if I only need two so I figured buy an assortment so I can have different sizes down the road. Mostly, I wanted to make sure the 1/4 watt was correct; all that stuff is a bit over my head for now but I appreciate your help and will be able to learn from this thread. Thanks again.
« Last Edit: January 24, 2022, 11:48:04 pm by Drakkorcia »

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Re: Reproduction Atari Volcano Switch Voltage
« Reply #8 on: January 25, 2022, 01:49:22 am »
Glad to assist.   :cheers:

Once your resistors come in, we'll do the testing, get you safely up and running, and maybe learn/confirm some details about these LED switches.   ;D


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Re: Reproduction Atari Volcano Switch Voltage
« Reply #9 on: January 25, 2022, 05:28:42 am »
There was a Facebook thread recently on volcano buttons and I mentioned the need to use a resistor with them, but somebody else commented that they now have a resistor built-in. Not a great authority, but there you are.

One thing we do know is that you can add another resistor, or use a higher value resistor, without breaking anything. The LED will probably still light, but with slightly lower brightness. Worst that can happen is the LED won't light.




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Re: Reproduction Atari Volcano Switch Voltage
« Reply #10 on: January 25, 2022, 03:37:47 pm »
There was a Facebook thread recently on volcano buttons and I mentioned the need to use a resistor with them, but somebody else commented that they now have a resistor built-in. Not a great authority, but there you are.

One thing we do know is that you can add another resistor, or use a higher value resistor, without breaking anything. The LED will probably still light, but with slightly lower brightness. Worst that can happen is the LED won't light.
That is consistent with the YT video above and Drakkorcia's experience using a ZD encoder.

Once we can reverse engineer the value of the resistor in the new repros, it looks like the best advice going forward is to do the inline amperage test described above to confirm the presence and value of the resistor since we don't know when a resistor was added to the repros but we do know that it wasn't in the original part.

For example, if they used a 150 ohm resistor so the LEDs conduct 20mA @ 5v . . .
https://ledcalculator.net/#p=5&v=2&c=20&n=1&o=w
. . . then by adjusting the LED current rating in the calculator you can figure out what would happen if you add a 220 ohm resistor. (370 ohms total -- the calc rounds to the nearest value 360 ohms)  The calc returns that size resistor with about 8.4mA.
https://ledcalculator.net/#p=5&v=2&c=8.4&n=1&o=w


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Re: Reproduction Atari Volcano Switch Voltage
« Reply #11 on: January 25, 2022, 07:30:42 pm »
You can go for much higher resistor values, if you want. it won't hurt anything.

For example on GreenAntz there is a power LED, a normal 3mm, 20mA rated, 2v green LED, powered by <5v, and I use a 68K current limiting resistor for that. The LED still lights and is bright enough to be easily seen, even if supply drops to 4.5v, and it only consumes a tiny ~0.04mA current. This is significant as the entire GreenAntz unit only uses about 80-90mA in total, didn't want to blow that out with a 20mA LED.

Viewed in this context, a 6.8k resistor for a volcano button LED does not seem unreasonable.
« Last Edit: January 25, 2022, 07:39:23 pm by Zebidee »
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Re: Reproduction Atari Volcano Switch Voltage
« Reply #12 on: February 13, 2022, 08:56:48 am »
I installed the buttons in my main full size 2 player cabinet and it looked out of place so I opted for the white P1 and P2 start buttons instead. I originally used the repro's in my A1UP 12-in-1 which is Atari themed and looked really good. My A1UP's were all reverted to stock with the intention of selling them but the Deluxe is a discontinued Gen 1 so I'll keep that one and put the repro's back in with a 5v source and 220 ohm resistor.