Connecting 12 Servo to Arduino

Hi all, I am building a spider-bot using an Arduino and 12 servos (at finish it will be 18 I am waiting for the Arduino mega to arrive) do I need to set something in my Arduino so it will be able to control so many servos?it seems that if I try to connect more then 2 it goes nuts.
Thank you.?

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You have a major power supply issue. How are you feeding them ?

Steve
YotamB (author)  steveastrouk5 years ago
I'm not sure yet, at the moment I use a 9v battery. I only run 3-6 servos at a time...
Once I will connect everything I will have to order something stronger...

But if I use an externel power supply can I connect servo to all the 12 I/O pins?

And how do I know what battery I need to run all the servos together?
frollard YotamB5 years ago
don't run the servo from a 9v battery that is powering the arduino - doesn't have enough juice!

Running more than one will definitely cause a problem! The arduino should be able to handle the signals, but not the power consumption.
YotamB (author)  frollard5 years ago
Thank you for the answers, I tested this and the power is indeed the problem.

Any tips on what kind of 5V 5A battery should I get.... there are so many kinds.

I will have to get it from a place like http://www.hobbyking.com for the international shipping,


Thanks...
I also added a picture of the spider-bot....
IMG_0244.jpg
frollard YotamB5 years ago
I recommend lithium with a high efficiency voltage converter to drop the voltage to something you can use.

I also recommend somewhere like dealextreme.com for the free shipping.
You will need a LOT of current - far more than you can get from a 9V battery - that's what's killing your circuit, as I said.

Guess at a minimum of around 5A, if all the servos were moving on load, from rest.

Steve