12v power source triggering nano reset?

Hello all! So I’m setting up my Nano to control a 12v LED strip through an N-channel mosfet in my RV camper. My intention is to use the camper’s existing 12v infrastructure to power both the LED strips and Nano simultaneously via the VIN pin (so I don’t have to buy dedicated power supplies). Basically this setup (but only a single-color LED strip):

However, My sketch will not run while the Nano is being powered by the camper’s pre-existing 12v wiresto the VIN pin (The Nano lights up, but won’t run Blink). I’m also finding continuity between the reset and ground pins while connected to the camper’s 12v wires.

The thing is, this is only true when the CAMPER’S 12v source is connected to the VIN pin, and NOT true when the camper wires are disconnected and I’m powering the Nano from something else, perhaps suggesting the board is resetting itself as a result of the camper’s 12v supply?

Thoughts?

Could you post a regular schematic of your project? Fritzing can do it.

I see an issue with your wiring... your gate pin needs pull down resistor. Not sure about your 12V power source issue though... that's different. Does it happen if you use a 9V source on VCC??? Is it possible your regulator is shot?

Automotive 12V supply is not suitable here - the strips want 12V at all times, not 13.8V sometimes
and less at others (I assume the 12V is standard lead acid with charging from alternator).

I would suggest a 12V to 12V DC-DC converter might be a way of giving stable and accurate
12V to the LEDs.

You may also have an issue of noise on the RV's supply, from other devices using it, or from engine
or alternator

I'm also finding continuity between the reset and ground pins while connected to the camper's 12v wires.

What? You cannot and should not be checking continuity when it’s connected to 12 volt power, you should only be making voltage measurements. If the reset pin is less than a volt relative to ground, give or take, the unit is being held in reset and is why blink does not run.

Further, I hope you’re using a proper meter for your measurements, not some bargain tester gadget that can damage a microprocessor.

You also shouldn't be feeding the nano 12v. The nano has an itty bitty shitty regulator on it that will overheat when supplied with 12v and you attempt to draw much of any current from it. Use an external regulator, or better yet, a DC-DC converter to generate 5v, and feed that to the 5v pin (you can do this on a nano or pro mini. You cannot do it on an Uno or other full-size board).

wolframore:
I see an issue with your wiring... your gate pin needs pull down resistor. Not sure about your 12V power source issue though... that's different. Does it happen if you use a 9V source on VCC??? Is it possible your regulator is shot?

I suppose it's possible, but I wouldn't know. Why are these things rated up to 20v or so if they can't handle it? I am able to get the setup working, my question is mostly why a power source would prevent the arduino from running the sketch.

MarkT:
Automotive 12V supply is not suitable here - the strips want 12V at all times, not 13.8V sometimes
and less at others (I assume the 12V is standard lead acid with charging from alternator).

It's currently plugged into the house, so I assume there's an inverter buried somewhere doing the conversion. Throwing a multimeter only shows a voltage variance of about +/- 0.1v. But I don't have enough experience to tell you whether that's a significant amount.

As I mentioned, I am able to get the LED's to do the thing like I want, but only when I DON'T connect the camper wiring to my arduino. That is, the lights work if I provide 5v to power the nano while pushing 12v through the MOSFET to control the strips.

My question is: Why can't this same 12v power supply also run the Arduino? I understand that it's best practice not to because of the heat buildup, but it occurs to me there's something going on the beneath the surface and I want to fully wrap my head around the mechanics of why the sketch won't run.

WattsThat:
If the reset pin is less than a volt relative to ground, give or take, the unit is being held in reset and is why blink does not run.

Further, I hope you’re using a proper meter for your measurements, not some bargain tester gadget that can damage a microprocessor.

I'm not quite sure I understand the reset pin. My understanding is that putting a voltage to it resets the arduino. In my tests, I found continuity exists between RST and GND if I use the existing camper 12v wires to VIN, but continuity does not exist between the same RST and GND pins when I supply the arduino with any other power source, including 12v from an alternate AC-DC adapter. So it seems the Arduino is perhaps resetting itself in response to some property of the camper's 12v wiring? But as I mentioned above, it's only bouncing .1v at a time...

Buck convert to bring rv voltage down to 5v for the nano. Then the rv voltage for the ledstrip and that works in my campervan.