Difficulties with controlling LED Strip

Greetings everyone.

This is my first project with arduino.
The idea behind is to control more LED strips by the use of a Logic mosfet, 30N06L in my case.

I am running into a small difficulty, at the moment there are 2:

1 - When powering the arduino from a 3s lipo battery the TX and RX LEDs light up and the arduino won`t work properly (this is not a big problem as I might use a converter and simply supply 5V, as it would be much healthier for the nano board)

2 - When connecting the MOSFET, in the off state the LED strip doesn`t switch totally off but dims slightly. I tried 10k resistor between gate and source, the 220ohm resistor between digital output pin and gate, nothing helped. Did I somehow manage to accidentally fry the mosfet?

In the attached schematic assume top rail is +12v, bottom rail +5v.

I have read other topics opened on the same problem, but their solutions, unfortunately, did not help me

In the attached schematic assume top rail is +12v

If I do that, I have to also assume that you are an idiot for having connected the Arduino's ground to that rail.

Do you really want me to do that?

Post a COMPLETE schematic.

In the attached schematic assume top rail is +12v, bottom rail +5v.

I don’t think that board will run on -7V.

A couple of things that may help:-

  1. The Nano can be powered from 12V as it has a built in 5V regulator. Simply connect the +12V to the Nano Vin pin and 0V to the Nano GND pin.

  2. Your Fritzing drawing does not show any current limiting resistor for the LED. Once you turn on the 30N06L (Which has an on resistance of approximately 0.035-0.045 ohms) you are effectively applying the full 12V directly across the LED. You really need to limit the current through the LED.

I suspect part of your problem comes from having no common ground connection between your battery supply and the +12V supply. This will be rectified by changing to a single +12V supply as suggested in 1) above.