I am using the arduino to dim on loop a 12 volt grain of wheat bulb via a transistor
which works fine.
To simplify the installation I would like to share the power supply for the
bulb and the 12 volts for the arduino rather than have two separate
supplies, as the installation will ideally be run from a pack of 12volt AA batteries.
Is there any reason I should not share the same power supply?
Can iI take a power lead from the bulb to power the arduino from the Vin socket.