180 degree Servo

Hi,

I looked in many shops and I can't find a 180 degree servo. Does it exist? (Maybe my research isn't good because I didn't use the right keywords.)
Should I try to learn and to hack an existing 60 degre servo or should I buy a full rotation one?
It's for a university project. I need to use the lightest and a precise rotor for a robotic arm.

Thank you,
Max.

I was in fact able to with Hobbyking finaly!

Funny most of my servos are 180 degrees (or close to it). I thought that is the standard. I have a box of some of the most common analog servos.. All 180.

The speed of the servo is sometimes given over 60 degrees. What spec and servo did you look at?

alka:
Funny most of my servos are 180 degrees (or close to it). I thought that is the standard. I have a box of some of the most common analog servos.. All 180.

The speed of the servo is sometimes given over 60 degrees. What spec and servo did you look at?

That's actualy the mistake I made.
I tought they were all 60 degre servos cause they only say the speed for 60 degree. I realized with some research that the angle is actualy way bigger if you use an arduino.

alka:
Funny most of my servos are 180 degrees (or close to it). I thought that is the standard. I have a box of some of the most common analog servos.. All 180.

The speed of the servo is sometimes given over 60 degrees. What spec and servo did you look at?

There is no standard for hobby servos. Most are in the range 120 to 150 degrees, manufacturers
vary, the only constant is that they can all control the flaps on a model plane's wing - that's what
they are made for.

Servo's spec'd explicitly for robotics will usually have more data (an actual datasheet if you are lucky)

MarkT:
There is no standard for hobby servos. Most are in the range 120 to 150 degrees, manufacturers
vary, the only constant is that they can all control the flaps on a model plane's wing - that's what
they are made for.

Servo's spec'd explicitly for robotics will usually have more data (an actual datasheet if you are lucky)

What's the difference between a servo explicitly for robotics and a for hobby? Is there a big price difference?

One is designed for robotics, the other is designed to waggle a wing flap... But I guess
accuracy, repeatability, torque, thermal management and movement range are all
desirable for robotics and much less relevant for RC hobby craft. IE quality can be
awful and you can still fly the plane - lightness is valued. There is probably a cross-over
where RC vehicle steering control is involved for instance.

MarkT:
One is designed for robotics, the other is designed to waggle a wing flap... But I guess
accuracy, repeatability, torque, thermal management and movement range are all
desirable for robotics and much less relevant for RC hobby craft. IE quality can be
awful and you can still fly the plane - lightness is valued. There is probably a cross-over
where RC vehicle steering control is involved for instance.

Well I'm doing a robotic arm! So I need a precise servo ^^ I didn't realize that some are not very reliable in term of precision.
I'm gonna try to shop one robotic servo this afternoon on the net. What should I type in the serach bar? How do I know if its an hobby or robotic servo?

Thank you for all that info! It helps me a lot.

The three very common servos I have here ( hitec, hextronic) all rotate 180 degrees ( plus or minus 1 or 2 degrees).

Even some hobby servos are quite precise. The difference in price is quite staggering from hobby servos to industrial/robotics servos.

Some of these are quite nice if you need precision.

http://www.trossenrobotics.com/c/robotis-dynamixel-robot-servos.aspx

alka:
The three very common servos I have here ( hitec, hextronic) all rotate 180 degrees ( plus or minus 1 or 2 degrees).

Even some hobby servos are quite precise. The difference in price is quite staggering from hobby servos to industrial/robotics servos.

Yeah my budget is around 15$, so no robotic servos :stuck_out_tongue:
How I am supposed to know if a model is precise? All the hitech and hextronic one's should be precise?

Unfortunately no, they aren’t that precise at that price range. As Mark said, good for moving a flap. They do get more precise when you get into the higher priced digital models but you will have to dig around on rc forums to find the best models as the manufacturers provide very little data.

Those were the cheap trossen models! Some are $2500 (if you need half a million individual steps per rotation!)

How I am supposed to know if a model is precise? All the hitech and hextronic one's should be precise?

You really need to do some research on google and youtube to find an arm similar to what you want, then see how it is constructed and the servos that are used. What is the level of precision you are wanting?