Multiple Servo?

Hi all, This is my first post so Hi, I have a question that i am sure will seem trivial. I have a project that uses 3 servos among other components. These servos require 4.6-6 volts is it possible to power these from the 5v vcc pin of an arduino? or would i need a higher power external power source. Cheers WCD

These servos require 4.6-6 volts is it possible to power these from the 5v vcc pin of an arduino?

No, you will need an external power supply for motorized components like servos.

hey, i've been searching alot regarding controlling multiple servos. all along i was under the impression that i had to use pwm pin outs for servos. however after reading the link at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1233181648/15 i got confused. mem said that we should not use analoguewrite but to use the timer2 library. so may I clarify that http://www.arduino.cc/playground/ComponentLib/Servo is the official servo library and it can drive more than 2 pins? so is it possible to use this library to attach servos to any pins? so if i have 8 servos, i can hook all of it up to my arduino duemilanove and use any pins that i want including a mixture of digital and pwm pins(with an external power source of course)? sorry for this long post, it's just that i've been searching alot and suddenly everything which i thought was right suddenly seemed disproved =/

thanks for the replies, dumbified i have looked through those links and it still appears zoomkat is correct with regard to the external power source. however with regard to the servo library as far as i understand it it is possible to use any digital pin for signalling the servo. Thanks WCD

The servo lib that comes with the Arduino environment can run 12 servos per timer it hooks into. Timer 1 is the timer it will take over for the first 12. And it doesn't matter which pins you connect the servos to.

scswift, when you said servo lib that comes with the arduino environment, what do you mean? does it mean that I do not have to download the library from the link that Iposted and the arduino already has the lib to run 12 servos?

ok never mind my bad, I just saw this http://www.arduino.cc/en/Reference/Servo so all I have to do is include <Servo.h> ?it’s such a pity the docs says that we can’t use pwm pins 9, 10 (as i have a duemilanove) as i was thinking of hooking up an LED as well as my servos… is it cause the library uses the timer of pins 9 and 10? oh and how may we check what version of arduino we have on our boards? im not sure if i have version 0017 or not.

The title bar shows the version number you’re using.

Yes, the PWM on pins 9 and 10 are disabled because that PWM is driven by timer 1.

There are other pins which support PWM though. You can hook your LED up to those.

Or you can pulse the led pin manually. I did something like 64 levels of brightness on an LED display with 64 leds by turning the pins on and off really fast.

yay i've just ordered 5 Hitec HS422 servos :) pwm on pins 9 and 10 are disabled but they can still be used to drive the servos right? so all i need now is an external power source. can someone give some insight as how i could hook all of it up to an external power supply?in series?

oh and what should i use? i've heart wall warts.. but i'm not too sure if that'll fry whatever components i have..

actually do you think 422 or 311 would be better for torque..

http://www.servocity.com/html/hs-311_standard.html http://www.servocity.com/html/hs-422_super_sport_.html

311 makes 42 oz/in of torque 422 makes 45 oz/in of torque

311 is marginally faster

can someone give some insight as how i could hook all of it up to an external power supply

@bld wow thanks, that really illustrates everything. But I have 5 to power, so do I just hook all 5 servos up in the same fashion as the one shown?

Simply substitute a proper power source for the 9V battery and everything else should be the same.

9 volt? Nine volts will blow a servo up in a nano second?

But I have 5 to power, so do I just hook all 5 servos up in the same fashion as the one shown?

You simply need either a 5vdc external regulated power supply rated at 3-5 amps or so, or a 6 volt battery rated with enough current capacity.

Lefty

So I would need a 5V power supply with 3-5amps of current or a 6v battery that can provide 3-5amps? alright thanks lefty! blowing up my servos.. i'll be very sad. i've been saving for quite a while to purchase the servos.

damn I cant find a wall wart at 5vdc with 3-5 amps at my local online stores. how do you guys connect your wall warts to the breadboard anyway? so looks like i’ll have to use batteries…

oh how did you come up with the figure 3-5amps btw lefty?

1A pr servo as a general guideline

And yes, don’t power the servos with 9v, it was only to illustrate how to connect to an external power supply… Going to make a new with the right stuff on.

Btw where is the 9v battery? My picture got two AA batteries, which would sum up to 3V...

oh he was just suggesting to use 9v batteries to power my 5 servos. haha. but i might have to use 4 batteries to make it into 6v.. hopefully with enough amps... but i have high doubts..

Ah okay, misread then. Thought he mention that I was showing you to use a 9v battery. But still going to make a picture with a voltage regulator in instead of the battery :)

Then may i suggest making this a sticky afterwards then with all the illustrations and answers in this thread? might be of use in the future.

Here is my attempt to make a better circuit. Notice that the capacitors on in and out is left out to keep it simple. But there should be one between in and gnd, and between out and gnd.