How best to get 5v power for push button lamp?

[misbehavens]

I'm working on my first control panel (which is powered by a laptop and a I-PAC VE). I bought a NovaGemCDR™ Coin Drop Replacement Pushbutton (http://groovygamegear.com/webstore/index.php?main_page=product_info&cPath=73&products_id=295) and would like to wire up the button's lamp.

As far as I know, the I-PAC VE does not have a 5v output for me to wire up to, so what is the best way for me to pull the 5 volts of power I need?

[DaOld Man]

Does the laptop have usb ports? You can get 5 VDC from one of those (but someone else might have a better idea, Im not familiar with the I-Pac VE.)

[Unstupid]

I'd pull it directly from your computer or arcade power supply.

[lanman31337]

The USB does 500 ma max I do believe.  I'd get it right from the power supply.

[alfonzotan]

The IPAC VE should have a 5V tap in the jumper block just like any other IPAC.  Grab a voltmeter and check the pins, here's the diagram from Ultimarc.

http://www.ultimarc.com/header.gif

I had no trouble tapping the 5V from my IPAC4 to run a few LEDs on my panel (with resistors, natch).  

[Smeghead]

I just used a



to power all my lights, lighted buttons, trackball

[Thenasty]

if you ever to need more than one v5dc or need 12vdc, here is a good one to get (you will have plenty for future connections of v5dc & 12vdc)

http://forum.arcadecontrols.com/index.php?topic=101280.0

[misbehavens]

Again, this is a laptop powered control panel. I will have an extra USB port available. This would be easiest if the port provides the correct power. The power requirements listed on the website say 100ma @ 5v DC Per button. I only have one button. Someone mentioned that USB ports do 500ma max. Does that mean USB would suffice for this scenario? If not, does that mean I need to run power to my control panel?

I'm assuming I can take an old USB cord, cut it open and tap into the black and red wires and use that to power my button. Am I assuming wrong? What else would I need to do to make this work?

Also, the tapping into 5v header on the I-PAC sounds like a good option too, as long as it is appropriate and will not damage the board by doing something it was never intended to support.

Thoughts?

[spkywlnt73]

I just used a



to power all my lights, lighted buttons, trackball

That's a pretty cool idea! How did you do it? Did you have to cut the end off of it?

[Smeghead]

yeah cut the end off and you have your + and  - wire

I actually used a 12v as I have quite alot of lights connected to it, coin doors, buttons, trackball and some LEDs
Plugged into the smartswitch it all turns off when the pc is turned off

Did the same for my pincab, one for the lights and another for all the fans lol

[DaOld Man]

Again, this is a laptop powered control panel. I will have an extra USB port available. This would be easiest if the port provides the correct power. The power requirements listed on the website say 100ma @ 5v DC Per button. I only have one button. Someone mentioned that USB ports do 500ma max. Does that mean USB would suffice for this scenario? If not, does that mean I need to run power to my control panel?

I'm assuming I can take an old USB cord, cut it open and tap into the black and red wires and use that to power my button. Am I assuming wrong? What else would I need to do to make this work?

Also, the tapping into 5v header on the I-PAC sounds like a good option too, as long as it is appropriate and will not damage the board by doing something it was never intended to support.

Thoughts?

The usb should power that ONE LED. It must be a pretty bright LED to draw 100MA.
The wall wart that smeghead suggested would probably be safer for the PC, if you have room for it.
Once again, I have no experience on the I-Pac, so not sure if it will supply 100 MA or not.

[misbehavens]

Here's what Wikipedia had to say about USB power:

"A unit load is defined as 100 mA in USB 2.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0. There are two types of devices: low-power and high-power. A low-power device draws at most 1 unit load, with minimum operating voltage of 4.4 V in USB 2.0. A high-power device draws the maximum number of unit loads. Every device functions initially as low-power but the device may request high-power and will get it if the power is available on the providing bus."

It sounds like the USB port will only provide 100mA by default anyway, so I think for the purposes of this button, hacking an old USB cord will suffice for now. However, if I ever plan to add more lights in the future, I now have some ideas of how to do it.

Thanks everyone!

[DaOld Man]

If anything weird happens, such as random PC reboots, I would discontinue use, but I honestly think it will be ok.

[AndyWarne]

Here's what Wikipedia had to say about USB power:

"A unit load is defined as 100 mA in USB 2.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0. There are two types of devices: low-power and high-power. A low-power device draws at most 1 unit load, with minimum operating voltage of 4.4 V in USB 2.0. A high-power device draws the maximum number of unit loads. Every device functions initially as low-power but the device may request high-power and will get it if the power is available on the providing bus."


Thanks everyone!

Thats actually incorrect. The 5 volts on USB ports is not controlled by the PC and the device has no ability to request the PC to supply more current. The 5 volts is connected directly to the PC power supply. 500mA would easily be available.
The way it actually works is USB devices tell the host how much power they use and the host keeps record of this and will display a warning if there is more than 500mA requested, but the host does not actually control the power available.

[Smeghead]

I just wouldnt even bother, with everything else plugged in its so easy to exceed the USB power available

[misbehavens]

Hi Andy,

Sorry if the USB info was incorrect, I was only quoting Wikipedia (which is not always accurate). I would assume you are quite knowledgable on the subject of USB power as well as the I-PAC VE. Can you confirm or deny that the I-PAC has a jumper suitable for powering this lighted button or if I should get 5v from the other USB port? I don't know much about electricity and current, so my fear is that I will draw too much power and damage either the IPAC or computer.

I'm looking for the quickest, cheapest, easiest solution since I only have this one lighted button to worry about. The 12v "wall wart" doesn't make sense to me because I only need 5v and at 100mA. Seems like so much power would damage my lighted button, but maybe I am misunderstanding the physics behind all of this.

[AndyWarne]

Hi Andy,

Sorry if the USB info was incorrect, I was only quoting Wikipedia (which is not always accurate). I would assume you are quite knowledgable on the subject of USB power as well as the I-PAC VE. Can you confirm or deny that the I-PAC has a jumper suitable for powering this lighted button or if I should get 5v from the other USB port? I don't know much about electricity and current, so my fear is that I will draw too much power and damage either the IPAC or computer.

I'm looking for the quickest, cheapest, easiest solution since I only have this one lighted button to worry about. The 12v "wall wart" doesn't make sense to me because I only need 5v and at 100mA. Seems like so much power would damage my lighted button, but maybe I am misunderstanding the physics behind all of this.

No need to apologise, it was Wiki which is incorrect! Yes you could easily power that from the header on the I-PAC.

Andy

[Heretik]

For anyone who may search this topic in the future:

You can grab any new/spare ATX power supply and find the main supply plug (for the motherboard header), it usually has 20-24+ pins on one header. First thing you'll want to do is jumper the GREEN to BLACK. This will signal the power supply that it is, indeed connected to a load. Then find any of the supplied 4-pin molex connectors:

RED = 5V
YELLOW = 12V
BLACK = Ground