Neopixel 60 ring won't work with separate power

[Icyyy]

I'm having trouble hooking up my Neopixel 60 Ring to an external power source. They work fine when drawing power and data from the arduino, but when I connect Vcc and ground from the ring to a 5V DC 3A switching power supply via a 2.1mm DC jack, adding a 4.700 uF capacitor, they simply won't light up. I measured the voltage over the DC jack, and it's roughly 5V (5.34V). What could be wrong?

[adafruit_support_mike]

Do you have the ring's GND line connected to the Arduino's GND? You need that for proper signal referencing on the data signals.

[Icyyy]

I see, no I did not. But it doesn't seem to solve it. Do I just connect Vcc from the ring to "+" on the 2.1 mm DC jack and leave the "-" empty?

[chadbone]

You need to hook the positive of the supply to the positive of the ring and the - of the supply to the - or gnd of the ring and also to the gnd of the arduino. So the neg of the supply goes to two places. That should fix it.

[Icyyy]

Thanks, but that doesn't seem to fix it either.

[adafruit_support_mike]

Post a photo of your hardware and connections and we'll see what we can find.

[Icyyy]

Photo 2014-04-16 13 00 13.jpg (911.94 KiB) Viewed 266 times

Red is 5V connected from + on the DC jack to 5V at the ring, the black cable is data from pin 6 on arduino (with spectrum shield on top) to data in on the ring, the other black cable is ground from ring to - on the DC jack, and then the - is connected to ground on the arduino via a black cable. The arduino is fed with a 12V 1.5A power supply and the DC jack with a 5V 3A power supply.