Same alimentation for Arduino and LEDs?

Hey! My project consists in an Arduino which controls a LED strip alimented with 12V so I put the 12V alimentation on the + on my breadboard.

I also have a Bluetooth receiver and a SoftwareSerial to link it to the Arduino.

The problem is that now I use an other alimentation, a 12V one for the Arduino. (So, I use two alimentations, one for the Arduino and one for the LEDs).

So I'd like to link the VIN on the breadboard so both the Arduino and the strip use the alimentation.

I tried, but when I do that the Bluetooth Serial begins to bug, receive weird characters except the first one which is almost always correct... And when I use two alims, all works like a charm.

Is my Arduino undervolted? If so, any solutions to use one alim for both or should I use two?

Why power an Arduino from 12V?
You’re just burning power and overheating the linear regulator.

(A hand-drawn schematic is far better than a description)

Just read on a website "Vin port allows between 7V and 12V". But if isn't ideal, what if I put a resistor and send 5V in the 5V port?

If it isn't a good way it could seem ridiculous, that's because I'm a newbie.

Thanks for your help

Use twelve volts if you must, but if you’ve got five, use five.

Connect the grounds together, but not the supplies.

But doing that I still need two power supplies no ?

It is possible that the single power supply cannot provide enough current for the full system. LED strips can use a lot current depending on their type and size.

If it can provide plenty of current what I would normally do is use a single 12V supply and a 5V DC-DC converter to supply the 5V to the Arduino.


But, shouldn't we provide 12V to the Arduino on the Vin port, and not 5V?

That’s correct, you shouldn’t power the Arduino from 12V.
It’ll get hot.

But, shouldn't we provide 12V to the Arduino on the Vin port, and not 5V?

No. If at all possible you should provide 5V for the Arduino to the 5V pin not Vin.