DJ Gave the best answer IMO

Long introduction is always good Everyone is pretty awesome on here! Some people to keep an eye on that you may wish to ping about how they accomplished stuff are

Bob Houston: https://synthiam.com/User/bhouston/Projects

Cochran Robotics (dave): https://synthiam.com/User/CochranRobotics.com/Projects

Dave Schulpius (b9 dave): https://synthiam.com/User/dave-schulpius/Projects

and of course Rich (inmoov bartender): https://synthiam.com/User/richard-r/Projects

Look at each of their projects to see where they're at. As you can see, they are pretty busy at their robots, but they've been known to chime in with assistance. If you're wondering how they accomplished some things, look at their posts because code is often published. Also look at their EZ-Cloud App projects. Most people have their projects available to download.

All other robots that are ez-robot favorites are here: https://synthiam.com/Community/Robots/

There's obviously many others, such as you've seen in your threads - but those 4 have been responsible for most of the features that you're interested in. They are always challenging me

@DJ, if you're still listening, You mentioned using the Auto Positioner control for positioning. I was under the impression that this control can only be used with servos and not a DC motor controlled by Sabertooth with a Kangaroo attached. Was I misunderstanding (which is very possible). My robot arm has a combination of servos and a DC windshield wiper motor controlled by a Sabertooth/Kangaroo. All commanded from ARC. I'd love to use the Auto Positioner control on this hot mess of mine but have avoided it because I thought the Sabertooth/Roo wasn't supported in the AP. Tell me I'm wrong please. eek

I'm still listening and very curious to know the answer! DE says they should ship my Roos today so next week will be power up time!

This is the URL to the kangaroo motion controller product: https://www.dimensionengineering.com/products/kangaroo

The description reads

[feature] Kangaroo x2 adds self-tuning feedback motion control to your Sabertooth or SyRen motor driver. It can be used with quadrature encoders or potentiometers to provide position or speed control. It supports one or two feedback channels.

Feedback control has always been highly desirable for mechanical systems. Being able to tell your device to move an exact amount, at a specific speed or to a certain position, and have it reliably and repeatably do so, regardless of the load or disturbances, has obvious benefits. However, PID and other controllers have to be carefully tuned to get acceptable results. Feedback tuning is difficult, time consuming and requires advanced math and physics knowledge.

Kangaroo x2 is the first self-tuning controller in its class. Instead of requiring you to measure, model and calculate the system, the controller itself will figure everything out after a few switch settings and button presses. In the time it takes to get a tasty snack, you can come back to a perfectly tuned system ready to accept your commands.

Instead of requiring you to use a microcontroller to do closed loop control, Kangaroo x2 works from analog and radio control sources as well as microcontrollers and computers. You can, for example, use it to build that two horsepower R/C servo you’ve always needed as the final piece of your doomsday device. Just remember who helped when the vaporizing starts.

During operation, you can command speeds, positions or combined commands like move to 37 inches at a speed of 4 inches per second. You can also have the Kangaroo x2 report back speeds and positions while it is running. A mixed mode allows for unstoppable mobile robots with differential drive or tank style steering.

If you need to get your product under control, Kangaroo x2 is the best way to do it. [/feature]

To summarize, connect the servo features of the kangaroo, can be found in the specifications section of that website...

[feature] Specifications: 2 channel self-tuning PID controller Position or speed control Quadrature encoder feedback or potentiometer feedback Support for limit switches and mechanical stops Analog, R/C and serial inputs [/feature]

What is relevant to this conversation is the R/C input and potentiometer. What means is, connecting a motor to a joint with a potientiometer, configuring the Kangaroo to work in R/C mode, will turn the whole mechanism into one giant servo.

Use the Auto Position control to control it.

Additional information regarding how to configure Kangaroo as a R/C mode servo controller would most likely be in their documentation - otherwise contact dimension engineering for instructions. Voila

@DJ... You need to give ez robot more credit... Sheesh LOL... You don't need a fancy kangaroo... I was able to create "that giant servo" with just a geared DC motor, a sabertooth and a 10k pot... With some nifty scripting I was able to control a dc motor like a servo... The pot spit out readings from 1 to 225 or so... With some simple math, I just converted it into a servo position from 1 to 180... Then what I did through scripting was to slow the motor proportionally the closer it got to the target servo position... If it over shot I reversed the motor... It was a little crude but worked actually pretty good...

@DJ,

Without the Roo, the Sabertooth has an R/C mode that should make it behave like a big continuous rotation servo, but no one has ever gotten R/C mode to work with an EZ-B (I haven't tried yet, my Sabertooth is still in a box, but others have).

Are you sure the R/C mode will work on a Kangaroo?

Alan

All I can do is quote their website and product information. If it doesn't work, contact Dimension Engineering for product support?

Have you ever connected an oscilloscope to an ez-b? You won't find a more stable servo controller anywhere. I am pretty sure we're the only controller that actually follows the servo specifications. Others slew the downtime as a constant, no matter the uptime of the pwm. The pwm specifications do allow that for servos, but it's frowned upon. Another reason why Arduino can't control servos without twitching.

So, if ez-b can't use a kangaroo in R/C mode, than no one can. Contact dimension engineering for product support is all i can say.