Powering a Nano with Vin - can't make it work

I have
1 Nano
1 nRF24L01
1 4xRelay board.
1 Breadboard plug in power supply
1 Breadboard

How do I connect all this so that the Nano, RF24 and relays are all powered by the one source?

I don’t care about opto isolation, nice to have if possible but can live with the risk if not.

Right now, I can’t find a wiring combination that works without a USB cable to a supply or the PC. That all works fine, but I do not want a PC or another power supply attached all the time.

So you have it all working when powered from USB.
Post a diagram of how you have connected that.

The biggest problem will be the 4-relay module, with 4x 80mA current draw.
The Nano can't power those four relays when e.g. a 9volt or 12volt supply is used on Vin (raw).

The easiest way is to use a 5volt cellphone charger with USB socket, and plug your USB lead in there.

I think you need an external power supply to power relay modules. It's not advisable to power relay from Arduino 5v. Relay can draw more current and might damage your board.

And you will also obtain poor result feeding the nRf module with the 3.3V of nano, there no enough current for it.

Ciao, Ale.

The "1 Breadboard plug in power supply" I mentioned above, IS an external power supply with a 12vdc-1A input providing both 5vdc and 3.3vdc rails.

But, by trial an error I finally have it working and nothing got fried. :slight_smile:

A breadboard power supply can't supply four relays (320mA) and the other items at the same time when powered by a 12volt brick.
The regulators get hot from the voltage difference multiplied by the current draw.
The limit of those small 1117 regulators is ~200mA with a 12volt supply at the DC jack.
A 9volt supply would be better (~350mA).
Less of a problem if you don't use all four relays at the same time.

IS an external power supply with a 12vdc-1A input providing both 5vdc and 3.3vdc rails.

Well, as long as whatever is connected to the supply doesn't exceed the specified regular maximum power output of the power supply, then ok.

I agree that the relay board should not be powered via the arduino's own 5V rail. They say the 5V rail source up to say 500mA. If only 1 of the 4 relays is used at any given time, then could get away with it, maybe.