Using a single 9v power supply to separately power arduino, motors, etc...

hi all -- beginner question here.

I have an arduino running that is gaining additional motors and small solenoids, etc.

I know that for my newest solenoid I should "power it separately" from the arduino.

But I am sure that I don't have to add a totally separate 9v power supply running from the power outlet in my wall, right?

For example, the power supply at my wall outlet is 9v, 2 amps.

So... can I take the power wires that come from that power supply and split it into two power line pairs lines... one to power the arduino, and another to power other devices?

Just at the moment, the second thing I want to power is actually small! it's a tiny solenoid, Mini Push-Pull Solenoid - 5V : ID 2776 : $4.95 : Adafruit Industries, Unique & fun DIY electronics and kits, 5V, 1.1amp. It can sort of actually run from the arduino power but that is feeling unstable when I do that, seems healthier to have its own power line.

In general, is there a method to split off from my single power line into two... and any tips on how to do it someday in the future when the power needs of the second device vary from my little solenoid today?

Thanks for your guidance... appreciate it

Eric

this question got no reply -- can anyone give some basic guidance? thanks!

Eric

The reason separate supplies are recommended when using inductive loads (motors, solenoids) with an Arduino is noise and spikes introduced onto the power rails by switching transients from the inductive loads. You can use the same power supply for the Arduino and loads if care is taken to filter the noise so that it won't affect the Arduino. Search Google for how to use automobile or car power with Arduino.

good tip -- I'll google that -- thanks!