Parallax has a new high-speed, continuous rotation servo with feedback!
Ken Gracey
Posts: 7,392
in Robotics
Comments
-Phil
@Publison. I'll send some of these to you guys in the coming days, so you can check them out.
Ken Gracey
Maybe you could do a second version of this with your narration. Some folks might not see the benefit of this type of servo without more explanation. Obviously, as a closed-loop servo this will be very handy in robotics, but it's application goes way beyond that in science class. Game changer, I'd say, especially at $19.95.
The difference in BOM costs for an ActivityBot with these servos will be [drum roll please. . . . . . .] $0.01 per kit.
But the real costs are in over a year of R&D, library support, kit revisions, and so on. The businessman inside of me wants to amortize these across our annual ActivityBot sales, which could double the cost of the ActivityBot.
Ken Gracey
the business men in you should say - let this season run the existing ones, redo the documentation/Example PROPERLY, and have a bright next year with upgrading.
And it is also positive for all the schools, after upgrading they have nice servos left for gripper-kits, moving Pings, whatever!
This is a cool product. Right on the point and with a good price.
Enjoy!
Mike
I always wanted to put a Prop chip inside a servo to give it better control, but maybe this is better...
If you add torque feedback, you could get into the micro market of torque controlled assembly screw drivers.
We will release a C library and Blockly support. From that, I'm hoping that our forum members can help us out with the Spin/PASM code examples. The most volume usage of this product will come in the ActivityBot, which uses the C library.
Ken Gracey
These servos would make that kit just about perfect. I do realize it would raise the price somewhat.
Position/velocity/torque feedback education is absolutely essential for understanding how real-world robots and machine-tools (CNC) work.
(Dreaming) it would be nice if someone came out with a CRS where you could specify a specific rotational speed and direction (6 rpm, forward).
BTW, the page for the product guide currently links to a zip file with C source code instead.
I seen that too, didn't unzip to see the content.
Fantastic product idea, have to build a new robot around them.
Couldn't you just add encoders to the bot?
https://www.parallax.com/product/32501
Yes, that's one solution. However, the point was more about what comes in the $179 kit - because everything else about the kit is great.
EDIT: I didn't mean to throw this thread off track, just wanted to mention these servos would be a perfect upgrade for the Arduino Bot kit.
Both downloads point to the same file. I unzipped then to check.
As for the Shield-Bot for Arduino, we'd like to achieve the goal DrPop suggested. As you all know, it's not a matter of putting the servos in the box. We need to write the libraries, test them out, revise the documentation, etc. These products go into courses where teachers are often very new to the subject, timid about their knowledge, etc. Everything must work entirely correctly, without any problems. Getting there takes time.
In the meantime, we can all watch a bunch of one-hit-wonder "STEM learning toys" pop up on KickStarter, delivering promises with an educational hook that some teachers will take. But if they wait and get Parallax they'll always be happy in the long run.
Ken Gracey
"Reason being, if the high and low pulses are sampled before and after a moving servo crosses the 259 to
0 degree boundary"
"This calculation returns 0 to 259 depending on the measured duty cycle."
Shouldn't these be 359 (0 to 359 degrees)?
Fixed! Thanks!
We will be frequently updating the guide and adding more resources over the next month - there is so much one can do with this servo that it will take a while to document all the possibilities. If you find any more typos or have other questions, just email editor@parallax.com directly so I don't miss it.
Pure coincidence that the minimum RPM I can get is ~6 RPM, but that stalls occasionally.