how to power ?

Hi, hi,

I'm new to the arduino world, so far I could do everything I wanted to but there is still something I don't quite understand.

My project is super simple, just one servo (Radio Control Planes, Drones, Cars, FPV, Quadcopters and more - Hobbyking42639__Turnigy_TGY_4805_2PA_Sail_Winch_Servo_Drum_Type.html), one arduino leonardo, and that's it.

When my board is usb connected to the computer everything's fine but as soon as I try to power it the battery it doesn't work, the servo is moving a bit but it seems to not have enough power.
I tried one 9V battery ( (+) to Vin, (-) to Gnd) and my servo was (+) to 5V, (-) to Gnd), it didn't work, so I tried with 2 x 9v batteries, one directly connected to +/- from the servo, and the other to vin/gdn on the board, didn't work either.
There is something I don't get obviously, can anyone help ?
Thanks !

A lost noob.

What kind of 9 volt battery? (the small PP3 will not work, not enough current capability)
That servo is 4.8 to 6 Volts only.
Warning, do not connect it to The Arduino +5V.

This kind of battery :

Why can't I connect it to the Arduino +5V ? How do I connect it if not like that ?

Those batteries will not be able to supply the current needed by the servo, plus, it is 9v while the servo is rated at 4.8 - 6V.
The Arduino is rated at 500ma the motor can take ~400mA.
This is too close to the Arduino maximum.
The Arduino should not be used to drive motors as these can put electrical noise on the system which can cause problems.
Power your servo with an external 5 volt power supply, connect the 0volt wire if this supply to the 0volt from the Arduino.

Why can’t I connect it to the Arduino +5V ? How do I connect it if not like that ?

It doesn’t supply enough current; see attached.

servo power.png

Pick up a 5 volt supply from places like this:

I would get 5v at 2amps.

Don’t know if it helps but you can build a 5v regulator.(Not my instructable)

Expect a small servo to take current peaks of 1A or so, larger servos more.
Never try to power a servo or motor from a logic supply, it can get expensive
if you are unlucky, it will probably crash the Arduino anyway.