Ws 2811 and arduino Nano Power supply

Hi there,
I am trying to create a music responsive frame with 34 ws2811 led.
The problem i have encountered is that when i try to power an arduino nano and the 34 ws2811 leds from the same power supply the leds refuse to turn on, instead if i power the arduino and the strip from two diffferent power supplies and wire them with a common ground the strip works fine (all the examples from the neopixel library).

Is there any way to have the strip and the arduino powered from the same power supply?
Thank you

Are you powering the LEDs via the 5v pin on the arduino or a direct 5v from the PSU? The arduino has a limited current it can supply so if from the board that would be your problem.

If direct from the PSU is it rated for the current you're drawing?

I am powering directly from the PSU, I have tried different ones. All of which can provide enough amps for the strip, if i power the strip from the psu and the arduino from the computer with a common ground the LEDs turn on just fine. If i power the arduino by means of connecting the v+ of the PSU to the vin pin of the nano and to the v+ of the strip and the v- of the PSU to a ground pin of the nano and to the v- of the strip and the data pin connected to a digital pin of the nano the strip doesn't work.

It seems as if i can't have a common positive, do you think an optocoupler could work?

ASAPELLA:
It seems as if i can't have a common positive, do you think an optocoupler could work?

Sorry, that is nonsense!

The "Vin" pin is not usable for any serious project. Please remember that. :roll_eyes:

Connect your fully regulated 5 V power supply to the LED strips and the correct "5V" pin of the Nano.

"Stock" explanation follows:


The clear blunder is not comprehending what the "Vin" or "RAW" terminal is. The regulator on the Arduino UNO/ Nano/ Pro Mini/ Mega2560/ Leonardo/ Pro Micro has very little heatsink, so will not pass very much current (depending on the input voltage and thus, how much voltage it has to drop) before it overheats and (hopefully reversibly) shuts down. It is essentially a novelty provided in the very beginning of the Arduino project when "9V" power packs were common and this was a practical way to power a lone Arduino board for initial demonstration purposes. And even then it was limited because an unloaded 9 V transformer-rectifier-capacitor supply would generally provide over 12 V which the regulator could barely handle.

Nowadays, 5 V regulated switchmode packs are arguably the most readily available in the form of "Phone chargers" and switchmode "buck" regulators are cheap on eBay so these can be fed into the USB connector or 5 V pin to provide adequate power for most applications. Unfortunately, many tutorials or "instructables" are seriously outdated or misleading and have not been updated to reflect the contemporary situation.

Paul__B:
The “Vin” pin is not usable for any serious project. Please remember that. :roll_eyes:

Thank you Paul__B this was what I was doing wrong