Atari LED/IPAC Voltage Question...

[WCBoudreaux]

Ok guys... I have a question, I wanna run by you guys, before I start hooking stuff up, and fry things... HEHE

Ok, I have an IPAC2... I have some atari cones, and LED switches that I got from RAM controls, (that guy rocks!) for my Space Ace...

The IPAC2 header has +5v power... The switches, are +2v ea... Now that you know what I have... Here's my question...

Since I have 3 switches to hook up (ie 2v+2v+2v = 6v) and the IPAC2 supplies +5v... I wouldn't really need any resistors since I have +5v, when I'd actually need +6v to supply just enough to the LEDs right? I mean, I know they wouldn't be as bright, which isn't a major concern to me, I just don't wanna burn them up...

Am I right in assuming this? Or am I way off?

Thanks in advance!

[Justin Z]

You are way off, and will probably blow up all three of your switches if you wire them directly to +5v.

I have about 24 lighted buttons on my cab which all require +5v and I've connected them to two sources of +5v, through resistors (albeit ones built into the buttons).  They are all very bright.

I am sure someone that has a better understanding about how resistance, amperage and voltage all work together will reply shortly, but I wanted to make sure there was a message up telling you unequivocally NOT to do that!

[Level42]

The LEDs in the Atari vulcano buttons are not 2V. Where did you get that info ?

LEDs are not so much depended on voltage. It's the current going through it that's important. You have to limit the current by putting a resistor in series with the LED.

On Atari game PCB's, the resistor is ON the PCB. So that's why you don't "see" it in a real game, but it's definitely there.

You should wire the LEDs in parallel, each it's own constant +5V and a switched common that is turning it on or off (don't now had Ipac controls that.)

If I am not mistaken Andy shows the correct way to connect everything on the schematics on www.ultimarc.com.

[Steve]

I have mine connected the same way (via a ipac) I used resistors and power from the PC power supply (I thinkNope, this was for the scoreboard)  I'll check this today and post back (with photo's)

Let me know if you need anything else

[Steve]

Okay,

I hope this helps you out. All you need to do to get the atari buttons working with the ipac is the following.
Use the normal button outs on the ipac, and use the LED pins on the ipac to get them to light up, I used a old internal USB ribbon cable to connect to the ipac's pins.
Now, as for the resistors (220R) I managed to find the corect ones at my local Radio Shack, I got 100 of them for $2 :-)
Now, on the Diagram image I ran the +5 volts to all 3 buttons and then the CAPS, NUM and SCROLL to each button. On the Ipac image this is where you need to get the power and lighting for the buttons

If you need anything else (photo's and so on) let me know and I'll get them for you asap (I want to see the final product  ) oh and I still need some parts 

I did this for my Space Ace and I also did it for my Marble Madness with no issues at all 

[Level42]

Yep, that's the schematic I meant.

[ahofle]

What kind of LEDs are in those things?  I know the IPAC doesn't have the current to drive modern superbrights.  You may need a 'driver board' like this one:

http://www.gamecab.com/products.asp?cat=26

That's basically what I use to light up my player 1 and 2 buttons with the IPAC LED functionality.

[Steve]

What kind of LEDs are in those things?  I know the IPAC doesn't have the current to drive modern superbrights.  You may need a 'driver board' like this one:

http://www.gamecab.com/products.asp?cat=26

That's basically what I use to light up my player 1 and 2 buttons with the IPAC LED functionality.

These are the Atari red LED buttons used on Space Ace, and that's the diagram I used to drive them.

[Level42]

What kind of LEDs are in those things?  I know the IPAC doesn't have the current to drive modern superbrights.  You may need a 'driver board' like this one:

http://www.gamecab.com/products.asp?cat=26

That's basically what I use to light up my player 1 and 2 buttons with the IPAC LED functionality.

The Atari Vulcano's used normal LEDs. There were no hi-bright LED's in the late 70's/early 80's !
Also, do the hi-brights really use (that) more current ? I doubt it.

[ahofle]

Ahh good, then you will be fine.

The Atari Vulcano's used normal LEDs. There were no hi-bright LED's in the late 70's/early 80's !
Also, do the hi-brights really use (that) more current ? I doubt it.

The IPAC doesn't have enough current for superbrights:
http://forum.arcadecontrols.com/index.php?topic=14980.0

[Level42]

Ahh good, then you will be fine.

The Atari Vulcano's used normal LEDs. There were no hi-bright LED's in the late 70's/early 80's !
Also, do the hi-brights really use (that) more current ? I doubt it.

The IPAC doesn't have enough current for superbrights:
http://forum.arcadecontrols.com/index.php?topic=14980.0

AFAIK a ultra-bright LED does NOT use (much) more current than a regular LED. 20mA is "standard". There's also 10mA and some 25 mA.

Where did you see the current limits on the IPAC ? I checked the Ultimarc site and there's no indication about it there.

The only problem you get is when you start running multiple LEDs on one such connection. If you connect 10 LED's to one connection, than of course the current drain is 10x20mA=200mA. I can see that the IPAC would be limited in that way, but I really don't see the IPAC having a problem with one ultra-bright LED per connection.

[ahofle]

The Ipac just provides a signal voltage for the LEDs.  I don't know the exact current (I've heard 10mA but can't find it), but those can be lower than 1.5 mA.  I really don't think Oscar and Gamecab would have bothered building LED drivers for IPACs if they weren't necessary. 

EDIT: from Andy himself, 10mA:
http://arcadecontrols.com/wwwboard/messages/39244.html

[WCBoudreaux]

Thanks guys! I knew I could count on you guys!  Beer and hotwings at my place! hehe

Steve, Thanks for that diagram... I had seen that before, but was unable to find it again after IE 7 decided it didn't like my favorites... And decided to delete them all...

Any how... I'll hit the radio shack up tomorrow and grab those resistors... Hopefully I can get as good a deal!

I'm not really ready to start the project yet, I have a UMK3 I'm working on right now, but you can rest assured, I'll be posting some pics! Of both projects!

Let me know when you get ready for those parts! 

Again, thanks guys for all in input, and very in depth info... As I said, I knew I could count on you guys!

[Level42]

The Ipac just provides a signal voltage for the LEDs.  I don't know the exact current (I've heard 10mA but can't find it), but those can be lower than 1.5 mA.  I really don't think Oscar and Gamecab would have bothered building LED drivers for IPACs if they weren't necessary. 

EDIT: from Andy himself, 10mA:
http://arcadecontrols.com/wwwboard/messages/39244.html

OK, I was already hoping for some input from Andy, but this is clear enough. Very weird, because in this case, even normal (20mA) LED's would be a too big load for the Ipac....Looks like you would need to use low-current (2mA) versions....

And WCBoudreaux, IE7 ?  Can't believe people are still using it when you can get two great alternatives for FREE:

http://www.apple.com/safari

or

http://www.firefox.com