Problem with servo Hitec

arm

Are Hitec servomotors continuos servos? Can I put them on my boe bot?
http://www.active-robots.com/products/motorsandwheels/hitec-servomotors.shtml
If they are standard servos, how many degrees can it turn?

schill

Hitec makes a continuous rotation servo:

http://www.hitecrcd.com/products/digital/robotics/hsr-1425cr.html

You can use these in a BOE bot. Note that the splines that stick out of the servo (where you connect arms, wheels, etc.) that Hitec uses are different from the standard that Parallax uses (which are believe are the same as Futaba). I believe this means that you can't (easily) use Parallax wheels with Hitec servos.

As far as I know, none of Hitec's other servos are made as continuous rotation. Of course, most servos can be modified to be continuous rotation.

Standard servos will typically turn through 90 degrees when used with radio control equipment (planes, cars, etc.). Most of them will turn through about 180 degrees when controlled using a microcontroller. There are servos that will turn through more, however. Typically, these have been used for things like winches on RC sailboats. There are also external gear packages that will allow them to rotate through 360 degrees (for example).

arm

Is this one a continuous rotation servo? HSR–1422CR
http://www.active-robots.com/products/motorsandwheels/hitec-servomotors.shtml

schill

arm wrote: »

Is this one a continuous rotation servo? HSR–1422CR
http://www.active-robots.com/products/motorsandwheels/hitec-servomotors.shtml

This links to the same servo as in your first post, an HS-7985MG. This is not a continuous rotation servo. You could probably a modify it to continuous rotation if you wanted to. But, it's a very expensive servo (they run $95 or so in the US). I would not recommend these servos unless you really, really need something they feature.

I don't think there has been a standard HS-1422CR servo from Hitec that is widely available. The only mention I find of them is one that was specially made by Hitec for Lynxmotion (www.lynxmotion.com). The standard Hitec continuous rotation servo is now the HSR-1425CR, which you can get from numerous places. They run about $13 to $17 in the US.

hover1

The HS-1422CR is the 3rd item down. It is a Continuous Rotation Servo, and it looks like it is in stock.

Be aware, as said before, the BoeBot wheels will not fit on these servos. Different spline size. Parallax Servos are Futaba

Jim

schill wrote: »

This links to the same servo as in your first post, an HS-7985MG. This is not a continuous rotation servo. You could probably a modify it to continuous rotation if you wanted to. But, it's a very expensive servo (they run $95 or so in the US). I would not recommend these servos unless you really, really need something they feature.

I don't think there has been a standard HS-1422CR servo from Hitec that is widely available. The only mention I find of them is one that was specially made by Hitec for Lynxmotion (www.lynxmotion.com). The standard Hitec continuous rotation servo is now the HSR-1425CR, which you can get from numerous places. They run about $13 to $17 in the US.

schill

hover1 wrote: »

The HS-1422CR is the 3rd item down. It is a Continuous Rotation Servo, and it looks like it is in stock.

You're right. I had to force a reload on that page a couple times for the whole thing to load. All I saw the first few times was the first servo. Something funny with my connection or something, I guess.

arm

Ok, thanks

Martin_H

You can make your own wheels by cutting a disk out of sintra, drill a hole in the center for the servo horn, and put a traction band around the outside of the wheel. Glue the servo horn in place with the horn going through the hole. That way there will be a lot of contact surface at different angles for the glue to hold onto.

The CBA robot kit uses this technique for its wheels and it works really well. The upside is that you are free to use any servos for your robot and not just those with existing wheels that fit their splines.