batteries with servomotors

Other Hardware General Electronics
1

Hello,

I have 2 servo motors which I would like to control with batteries (they have to move at the same time). I had no idea how to calculate the voltage necessary so i just used a 9v. the red wire is soldered to the red wires from the servo and the black one together with the servo's cables to gnd. the website i ordered them from says Voltage 4.8V ~ 6V and
5V 6V
Onbelast 440 mA 630 mA
Belast 1000 mA 1100 mA

the servos don't move without power from my computer.
I'm pretty sure it is because of the batteries so could somebody explain how to calculate the necessary voltage?
thanks a lot!

2

Well if the website says 5-6V, there's your answer, no calcs required.

You might have damaged the motors with the 9V I suppose.

BUT.... you say nothing about the yellow wire, which is what controls a servo from some kind of I/O pin like on an Arduino, along with the necessary program code. A servo doesn't run like a "normal" motor just by applying power to the red and black.....

3

the yellow cables are plugged in as well.
but i saw a guy at school using a 9v just to power a led and that worked fine.
but thanks i will see if i didn't damage them and try a lower voltage

4

And you have a sketch running too?

You should post more detail, like the sketch and the circuit if you want meaningful help.

Your friend with 9V on an LED... does he have a resistor in series?- else he's going to burn it out.

5

just hooked it back on the computer, the motors still work and the code is fine. my circuit is exactly as in the image, i followed this tuthttp://www.robotoid.com/appnotes/arduino-operating-two-servos.html
the only problem is what kind of battery i need

2servos.png

6

timmie:
just hooked it back on the computer, the motors still work and the code is fine. my circuit is exactly as in the image, i followed this tuthttp://www.robotoid.com/appnotes/arduino-operating-two-servos.html
the only problem is what kind of battery i need

Servos are usually rated to operate at 4.8 to 6.0 vdc. Four AA cells in series would probably be your easiest choice.

Lefty

7

Forum member DuaneB has some useful tutorials on servo power. I use 4x 1.5V batteries... in fact they're rechargeables which are only 1.2, so I'm on the lower edge of the 4.8 to 6V scale, and they work fine. Admittedly, they're not lifting huge loads....

8

thank you both, I will use 4x1.5 now