Uno, HS-805BB, and LM2596 Step Down Buck Converter

I'm working on a project to automate a child's Power Wheels (ride on car) toy, and I need to find a good power steering solution. I'm using an Uno to drive an HS-805BB servo, being fed 6V from an LM2596 based buck converter from eBay, coming from a big 12V battery. I believe the servo is getting enough power, but it's not working under the weight of the car, let alone any riders in it.

Is there anything I would be missing in this setup to get more torque? I'm using the Servo library in Arduino and it works great without a load. Should I get a bigger servo (or linear actuator)?

Thanks a lot

I wonder what is the stall current for that big servo? I can't see it on the link you posted. I could well believe it is more than 3 amps.

...R

Thanks, you're right, it's not listed and I can't seem to find it online. It does appear to be pretty high, and that would explain what's happening.

Sorry, I'm new to using servos. I'll see about increasing the current available (even just a striaght up 6V battery for testing).

Perhaps a better final solution would be using an RC rated UBEC that supports the rated current?

Perhaps a better final solution would be using an RC rated UBEC that supports the rated current?

THE UBECs are made for supplying large currents to servos. Your converter may not be able to handle the large currents (do you have a link to what converter you have?).

I'm running something like this from eBay, I think it's 1A with a possible peak at 3A.

But, I think it's definitely under powered. The UBECs will take some time to come in (thanks China :)), and I have some extra Buck Converters. So I think I'll put a couple in parallel and see if that at least helps a little to know if it's the problem.

If I can get this giving the power I think it should have, then I might consider adding another HS-805BB and run them together.

Goines: I'm working on a project to automate a child's Power Wheels (ride on car) toy, and I need to find a good power steering solution. I'm using an Uno to drive an HS-805BB servo, being fed 6V from an LM2596 based buck converter from eBay, coming from a big 12V battery. I believe the servo is getting enough power, but it's not working under the weight of the car, let alone any riders in it.

Is there anything I would be missing in this setup to get more torque? I'm using the Servo library in Arduino and it works great without a load. Should I get a bigger servo (or linear actuator)?

Thanks a lot

You'll need much more rugged mechanical components for a steering servo, probably a 20W DC gear-motor with 100rpm output and decent actuator arm fitted to the output shaft. You'll need some sort of encoder and a closed-loop feedback to turn the whole thing into a position servo. Expect many kgf of vibration for this application, much more than a plastic bodied RC servo can handle without breaking.