Mobile Control Panel with ipac ultimate, wiring questions

[hycday]

Hello everybody,

I am currently under the construction of my first arcade bartop cabinet.
I intend to have a control panel that can be removed in order to get a smaller/lighter bartop to be used as a jukebox/computer
My control panel will have 2 joysticks, 20 ultralux RGB buttons, and 4 regular buttons (no leds). I have an ipac ultimate i/o and it is powered via a molex 5v.
If I am correct, with 20mA per color and per button and per joystick (correct me if I am wrong), I would have a total of :

(20*3) * (10 *2) + 20 * (2 *2) + 20 * (1 *2)
10 rgb leds * 2 players + 2 buttons * 2 players + 1 joystick * 2 players
= 1320 mA

As you can imagine, the molex power source, and the 'removable' control panel might be incompatible.
Thus I would need a power source of 5v / 1.5A (or 2A to be sure).

To ease this up, let's imagine I intend to have a control panel to be used with a laptop.
I would plug the ipac with usb to the laptop, and I need to have a power source on the other hand (since I intend to use more thatn 500mA).

However, Andy notified me of the following :
"You could try a wall adaptor but I have heard reports of interference causing issues. You might need to run an extra ground cable from the negative of the power supply to the PC casing or other ground point."

Also, from ultimarc website, I read the following :

"The LED harness and the PCB take 5 volts from the PC motherboard. Ensure no exposed parts of either touch to ground. If this occurs the motherboard could be damaged. Most motherboards supply the 5 volts to the keyboard connector via a tiny wired-in fuse which looks like a resistor. If the 5 volts is shorted this fuse will need to be replaced which is not easy!
Mount the PCB on a wooden control panel or other insulator, or if this cannot be done, use stand-off pillars. When the LEDs are connected to the harness a small length of pin is left exposed. This can be bent over to secure the plug and should be insulated with tape as one pin on each LED is connected directly to 5 volts."

From what I understood, this needs to be done in order to avoid burning my laptop/computer or the ipac.

I was planning on simply buying something like this : http://www.ebay.fr/itm/Adaptateur-Secteur-Alimentation-Chargeur-AC-DC-220V-5V-1-5A-1500mA-7-5W-5-5mm-/321033935027
but the ground issue will still remain.

So I have two options :

First would be buying an extra cable with ground (the big ones, in France they are called type E/F, the right one on the below picture) and buying this adaptor and opening it (let's assume it is the one on the left of the picture, I couldnt find a picture of one opened...). I would wire any of the pin of the adaptor (AC side) to neutral cable, the other one to phase cable, and on the DC side of adaptor, I would identify the negative and wire it to the ground cable.
Would this be ok ? if yes, I still dont know of to "secure" this and not have cable everywhere...
This is a picture for better presentation :



Other option would be to buy this little thing : http://www.ebay.fr/itm/Adaptateur-secteur-bloc-alimentation-AC-220V-12V-5V-2A-MOLEX-IDE-Disque-Dur-HDD-/221272754346

I would simply use the original provided power cable "molex 5v to 5.5mm/2.1mm male barrel" (if any of you knows where I could buy one please share, as mine broke....) and plug it to this adaptor
and on the other side (AC) I would buy an IEC cable with the same head as the picture above (right part, with ground)

Only thing would be to be sure that when on 5V mode, the ground is still wired. Also, I read on sparkfun "Never buy this. Voltage drops from 5V to 3.5V under less than 1A load. Bought two of these, going to throw away both.", so if you know where I could find one that is good and efficient, please share !

That's all, I hope I was clear and that I did not say any silly stuff. I am really a noob in electronics but I want to learn that and do it properly so I am looking for any advices/help/comments/ideas !

Thanks a lot