VIN powered by regulator???

Hi,
With an Arduino Nano I'd like to switch and power a motor with 5V wich draws 200mAh. So I use a transistor (1k Ohm resistor at base) and connected the collector to VIN. I thought VIN was directly connected to 5V of the USB input, but the regulator of the Arduino gets extreamly hot when the Motor runs.
Did I miss something?

Vin connects to the input of a regulator which produces 5v on its output .
From your description I can’t see how that worked anyway but ....

You can’t run a motor load using a nano as the power supply - not only current limitations, but it’s likely to create electrical noise , leading to
Other problems

You can ignore the transistor. It's only for switching the motor on and off. The motor is connected to VIN and OUT. And I thought, I would bypasss the Arduino and the regulator and would draw directly from USB, but why does the regulator get hot then?

It seemes like there is a doide in between and I don't find any proper schematics.
My main question is: Where can I solder the motor to get USB power?

Most voltage regulators (not all) have an internal reverse protection diode between their input and output.
If you power the regulator on it's output (5volt USB), and draw current from the regulator's input (V-in pin), then current flows backwards through the regulator.
Good way to fry the regulator.

Possible (but dangerous) to power a motor from the 5volt pin of a Nano (= 4.6volt on USB power).
This could fry the USB backflow protection diode (500mA absolute max) or freeze the MCU (motor noise).
Best to power motors from a separate supply.
Leo..

Thanks for your answer :slight_smile:
I made some tests and figured out, that my circuit worked fine. It semes to be a totally different problem with the regulator :frowning:

See this topic: link

I thought VIN was directly connected to 5V of the USB input

No, the VIN pin is connected to the input of the regulator.
The 5V pin is connected to the output of the regulator.
The USB 5V source connects to the cathode of a Schottky diode, anode to the output of the 5V regulator.

Your error is that a 5V supply should be connected to the 5V pin, not VIN, which needs at least 6 volts for the regulator to operate properly.

Ah, thanks for clarifying :slight_smile:
Nevertheless this was not the cause of the regulator heating up.
The regulator even starts heating if I don't pull any current from the arduino but if the Arduino is attached to a powersource with fluctuating voltage. I changed the source to VIN instead of USB and power the motor from the same wire, so no current should flow through the Arduino but the problem remains. The motor pulls 150mA and the regulator pulls 600mA when the motor was started once.
See this circuit: link

com___:
Ah, thanks for clarifying :slight_smile:
Nevertheless this was not the cause of the regulator heating up.
The regulator even starts heating if I don't pull any current from the arduino but if the Arduino is attached to a powersource with fluctuating voltage. I changed the source to VIN instead of USB and power the motor from the same wire, so no current should flow through the Arduino but the problem remains. The motor pulls 150mA and the regulator pulls 600mA when the motor was started once.
See this circuit: link

At the risk of repeating myself: You cannot power a Nano with a 5 volt supply by connecting it to the VIN pin.

Additionally, you absolutely need a freewheeling diode across the motor to prevent damage to the Nano. Continuing down your present path will result with you starting yet another thread titled “my Nano just stopped working”.

BTW: Motors make lots of noise. Your chances of actually doing anything with the Nano in this connection scheme are next to zip, nada, zero.

A flyback diode didn't solve the problem. Waiting now for a dc controller to arrive