Let's Make Robots!

A Servo Query

Hi LMR's,

I recently bought 6 servos from here: http://robokits.co.in/shop/index.php?main_page=product_info&cPath=2_5&products_id=187 .

It says to be Exact replacement for Futaba S3003 and Hitec HS-311.

In most of the website and the official arduino page I read that u simply can run one from an arduino,but in my case it didn't :-(

I tingered around with the circuit and supplying +5V from a seperate battery with its gnd connected to arduino it worked.

So I was wondering

1) Do we need to supply seperate +5V to servo's for it to work ?

2)Did it work in your case by simply hooking the 3 wires DIRECTLY with arduino?

3) What in case I need to power multiple servos(in addition to the arduino)Won't that be a lot of batteries?

Also I was wondering if an arduino provides more sinking current at its pins compared to lets say a bootloaded clone?



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I have a lot of servos and Arduinos, some made in Italy and some Chinese clones. Even when I hook up a small micro 9G servo the micro controller resets. You need a much more powerful regulator to power servos then the one on the Arduino boards. For this reason I've designed a couple of boards with 3A 5V regulators. https://vimeo.com/44338609

This Arduino reset problem occured to me to. On several original Arduinos. With the common 9g micro servo. Having a 470uF capacitor between the servo VCC and GND reduced the problem to an acceptable level.

As I understand he writes that it didn't work at all. No move. Nor any noise. Nor any shivering. Nothing. So would you still guess this is related to the Arduino reset problem? 


I am not sure I agree with Arduino running servos directly, check out these two links for lots of detail on trouble shooting Arduino and Servos -



Duane B



Sounds like your problem is in the Arduino. In my limited experience, when you fry an Arduino, the problem is usually in the power system. Since you're talking about replacement servos, can you see if the one you're replacing will work when you supply it with the separate battery like you did the new one? You could try augmenting the USB line power with a battery, but I think there's protection circuitry that will foil this idea.

to run your servo. Your arduino should be able to supply the needed current for a single servo. If for some reason you need more current, you should be able to splice into the battery positive before you feed it to the arduino and as you did, share the grounds.