Questions with a LED strip

Hello there. I have a RGB LED strip (not of those that you can control each LED individually), but I need your suggestions and advices in these issues:

  • I'm gonna use an Arduino Nano for my project.
  • The strip uses 12 volts, so can I use that voltage to power up my Nano board?
  • I want to fade in and out the LEDs, so I need to know which pins give me a PWM output (and what number they have in the IDE).
  • Which would be the best MOSFET transistor for my kind of LED strip?
  • I'm not quite sure, but what if my LED strip has common cathode?
  • Does the MOSFET's gate need a pull-off resistor?

I hope you understood my questions and I will appreciate your attention.
And by the way, the RGB LED strip that I was talking about from the beginning, is one of those that the four pins are: Red, Green, Blue, V in or Ground.

Yes you can power the both with the same supply.

Those strips are not common cathod, you ground the R G or B lines to make it light.

PWM pins have a ~ next to them in the board. What pins these are depend on the board you have.

Get a logic level FET.

A FET does not need a pull down resistor but it is a good idea.
There are lots of examples on the net for this sort of circuit. Google is your friend.

AOI514 from digikey.com works well.
I have 32 on this board to drive LED strips with 74H595 to drive the gates, pulldown resistor to hold the gate low should the 595 outputs be disabled.

Lucario448:
I'm gonna use an Arduino Nano for my project.

Okay, fine :slight_smile:

Lucario448:
The strip uses 12 volts, so can I use that voltage to power up my Nano board?

Yep, just connect it to Vin

Lucario448:
I want to fade in and out the LEDs, so I need to know which pins give me a PWM output (and what number they have in the IDE).

Google is you friend :wink:

Lucario448:
Which would be the best MOSFET transistor for my kind of LED strip?[

The first logic level N-channel MOSFET you can find. Like IRLML2502, IRF7313 or IRL3705

Lucario448:
I'm not quite sure, but what if my LED strip has common cathode?

No, common anode, way easier to drive :slight_smile:

Lucario448:
Does the MOSFET's gate need a pull-off resistor?

Like said before, you don't need it per se but a pull down connected to the gate will keep the LED's off when the Arduino is in reset/starting. So it's a good idea :slight_smile:

OK thank you guys. Now I realized that I missed to ask you something: what value does the "pull-down" resistor must have in my case?

Thanks again :smiley:

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