Neopixel strips does not light up with power from PSU but do

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harald25
 
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Joined: Sat Feb 06, 2016 9:29 am

Neopixel strips does not light up with power from PSU but do

Post by harald25 »

Hi.
I've wired up 2x 5m Neopixel strips to a computer PSU.
The two strips are connected to two separate 5V and GND, and my Arduino UNO also has a separate 5V + GND.
(I believe all the GND connectors fuse together inside the PSU, so that they are in fact all connected to common ground)

When I switch on the PSU, nothing happens. Except the "on" LED on the Arduino lights up.
If I connect a USB to the Arduino, but keeping everything else the same (power from PSU to neopixels), they all light up!
I'm confused as to what I might be doing wrong. Why isn't anything working when I try to power the Arduino with my PSU?


PS: I'm quite new to electronics, so I would appreciate noob friendly answers ;)

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adafruit_support_bill
 
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Re: Neopixel strips does not light up with power from PSU bu

Post by adafruit_support_bill »

It is not a good idea to rely on the power supply ground for controlling pixel strands. There is a lot of current flowing through that ground wire so there is likely to be a voltage drop which will affect your signal reference.

The best way to do it is to run power to the strip, then run +5v and GND from the strip back to the Arduino. The Arduino current oad i very small, so the voltage drop will be insignificant.

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