I have to build a timer that powers an electric motor using a relay module, but I want to power the motor and the Arduino Nano board from the same power outlet (220V 60Hz) by putting the motor and the board circuit in parallel. For this, I need a module that drops the voltage from 220V AC to 7V-12V DC so that I can power my Arduino Nano through the Vin pin.
Can someone please help me by suggesting a module or circuit solution? I do not want to power my project by usb cable.
You can just leave the Nano powered through that USB cable hooked to a phone charger "wall wart", or rip open a USB cable to get 5 volts which (check me on this) can be fed to the 5 volt pin on the Nano and also be the source of any other required 5 volts power.
OK, checked myself. Yes, 5 volts to the 5 volt pin.
To be totally safest, use the USB gazinta during development, then hook the external 5 volt supply to the 5 volt pin.
Even though a real Nano can have USB power and 5 volts fed at the 5 volt pin w/o any problem.
A phone charger/USB puts typically about 5V, a bit short of the 7-12V wanted. You can Purchase what is referred to as a "Wall Wart" (12V plug supply). I purchase them for a few dollars rated at 12V, 2A. This will work fine but you do not have more then maybe 50 mA or so available on the Arduino 5V pin. Lowering the 12V will give you more available current. Exceeding this will cause the regulator on the Arduino to get hot and shut down.
Do NOT tie the Arduino power to the LINE. This will place your entire project at dangerous voltage levels - even when OFF!
However you power your project, you MUST have galvanic (ohmic) isolation between the LINE and all voltages in your project.
The "Wall Warts" are typically transformer isolated so you automatically get galvanic (ohmic) isolation. If they did not imagine the number of fried cell phone users. You can validate that by being sure it has a legitimate UL or CE label.
