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Asked — Edited

Dimension Engineering Experience

Just thought I would tell everyone about a great experience I had yesterday.

I have been keeping up with all the treads about Dimension Engineering's Kangaroo in here, as trying to keep my robot on a straight path has not been very successful.
Now that Tony has been working with it and adapted it to the V4 I thought it was time to take the plunge.
No need to order it off the net, I only live about 10 minutes from where it's sold, so off I went for a drive.
So glad I did!
I walked into the business and was greeted by a very nice and polite young lady ( very pretty too ...lol).
Anyways, I asked to purchase a Kangaroo and she went and got one.
Well as she was ringing up my bill I began a conversation asking her if they assembled the Dimension Engineering items here.
She said we not only assemble them here but make them as well.
Wait I said, electronic items actually made here in the states.
She said they make everything they can here, even machining there own heat sinks for the items.
She then asked if I would be interested in taking a tour around the place.
Interested, I kill for a tour!
She took me all around showing me every machine explaining each.
I was in heaven as we went from one to another.
It was amazing to see how boards are built and the machines it takes to do it.
Then as we past a very young looking guy she introduced me and said this is the owner.
Owner, I was blown away that such a young guy could be the owner of such a great company.
(Later when leaving I mentioned I can' believe a guy as young as you can own all this, his reply, well I'm not as young as I look, I'm 33 ... LOL.)
I ask who was the developer of the Kangaroo and he said he was.
I told him that the guys on the EZB forums talked very highly about the Kangaroo and thanked him for his help a couple of time that he posted.
He said he would like to do more of that but running the company takes up most of his time.
I said that's understandable.
He then said he had to get back and thanked me for coming.
After looking at all the assembly machines she took me to the machine shop and showed me how it worked.
Getting ready to leave and say goodbye she asked if I had ever heard of a company called Tiny Circuits, yes I said, and she told me that company is own by her husband and if I ever wanted to tour it she would ask him to show me around.
It was really a great experience and as I was driving home I was almost on a high ... LOL.

I have for the past several years been very interested in electronics from circuit designs to how it all comes together.
Seeing exactly how it works, or at least the assembly part was pretty cool.

Hope I didn't bore anyone here, just wanted to share with someone that might appreciate it like me.

Herr

P.S. I now see they have spell checking here, GREAT idea!

#5  
Thanks for the report. Next time photo or video too, please...

j
#6  
@jdeBay.... "Next time photo or video too, please" .... you sound so demanding with that statement.... Tony has other things to do....
#7  
Thanks for sharing your wonderful trip with us. We saw it through your eyes.

It was Great!
#8  
@Herr, What luck and fun! Where are they located? I had no idea they were a smaller company. This explains why it sometimes hard to get support or deep helping answers. If the owner is one of the only ones responsable for customer support, keeping the company running and R&D then I bet he is overwhelmed most of the time. Still to have them stop and give you the grand tour says a ton about the mind set of the company and what they think about the user.

DE's line of product is excetional and dam near bullit proof. I use two Sabertooth/Kangaroo combo boards in my B9 and plan to add a third at some point. Once dummies like me get past the learning curve and get it set up properly it really is quite easy to run. I do hope they are able to "strighten" the curve a little more so it would not be as diffacult to set up and understand for the new user. Perhaps a Sabertooth/Kanagroo for Dummies approch in their manuls and a user forum like EZ Robot has.

@Tony, I truly hope they can find the cause of the half speed problem. It would be a shame to have to go to a different drive system. I think I read somewhere when I was settting up my boards and trying to overcome problems I was causeing about this problem and a fix (hopefully) on a forum somewhere. I'll have to go back and look. It should not be too hard to find as there isn't much out there on the web conserning Kangaroo x2. I was having setup problems like the Kangaroo loosing the tune and not starting if I stopped it over night next to a limit switch. I would have to retune it each morning. Turns out the battery would keep the Kangaroo/Sabertooth powered up after I shut down the robot, slow trickle down to dead and that whiped the memory in the kangaroo. I had to make sure the kangaroo was also disconnected from the battery at the same time the robot was powered off and all was well after that. DE was right there with many emails and suggestions but my trial and error found the right solution. I dont know what the message to you is in my experance but it may help somehow. ;)
#9  
@Dave

Dimension Engineering
899 Moe Drive #21
Akron, OH 44310
#11  
@Toymaker, in mixed mode, the Drive channel is derived from the sum of the two channels' motions, and the Turn channel is derived from the difference.

So, "drive 100/s" is the same as "M1 50/s" synchronized with "M2 50/s". That may be what you are seeing.

If the number you are commanded is being limited by the maximum speed, the retune for mixed mode should have determined the maximum speed properly, which would be twice what it would find in independent mode (for the reason mentioned above). If not, you can certainly alter the setting.

In Live Test, is it sending 100% throttle (if one chooses 'show commands also') to the Sabertooth?
United Kingdom
#12  
James, I stopped developing with the Kangaroo as I had these speed issues which were possibly caused by the motor encoders being too high resolution (63500 pulse per revolution)? I do plan to try again with the Kangaroo, as I really like this hardware.

Is the Kangaroo max pulse input 80000 for one motor, meaning that its 40000 for two motors as in mixed mode it has to read two encoders simultaneously? If so then a divide by two (say 4013 D type flip flop) is what I am looking at. This would reduce the 63500 pulses (per revolution) down to 31750, hopefully the loss in accuracy will be negligible, what are your thoughts on this?

Another thing I do not understand is I have been told that 80000 pulses equates to 20000 lines, what is a line?

I think Dave mentioned that DE had updated the DEScribe software, so I may need to look at this also.

Tony
#13  
Tony, Last year DE contacted little old "me" telling me that they had a beta version they have useing in the lab that added speed ramping for position mode, They call it a acceleration limiting feature (and it works great). They also included a new version of the Describe software that had some differences that even my novice eyes saw. Mainly in the live test section. I don't know if there was any other upgrades in that beta version and I don't know if it's public yet. Then a month later they emailed me a "bug" fix for some issues that Beta was having.

DE is a great company that truly tries to give great customer support and actually listens to the customer (reminds me of EZ Robot). I really hope you are able to start using the Kangaroo and Sabertooth again. Once you talked me into reevaluating my decision to dump the two control boards because of my newbie flustration. I'm so glad you did as it's really made the difference in controlling the motors in my robot. Hopefully you can do the same someday soon. ;)
United Kingdom
#14  
Dave, dont get me wrong, I really like the Kangaroo/Sabertooth combo, it is a great product!

My problem was that it took 33 emails to the DE support (Charlene) to possibly ascertain that the Kangaroo probably could not handle the encoder "ticks" that I am using, and I started to lose a bit of interest and I wondering about rolling my own PID motor speed controller out, although I would prefer to use the Kangaroo as I have already invested a huge amount of time trying to get this product working on my particular setup.

I believe @James may be the designer of the system, and his reply (above) is welcomed, but it has been a year since my original post on this, so he probably does not look in very often. Maybe he can help now, and I can go back to using the Kangaroo.

Tony
#15  
Does anyone know the easiest way to control a Kangaroo/Sabertooth setup from ARC? Is there any little panel that would give variable control for both channels in mixed or independent mode or do I have to write a script?
#16  
@Purple... There is no direct way ( maybe via a POT) to connect the kangaroo/sabertooth directly to the ezb... I believe Tony uses a PIC to record/count "ticks" for PID control... I assume an arduino can do it as well....

If you just using your sabertooth as a motor controller (no precise movements like with servos) than you won't need a kangaroo... The sabertooth alone can do variable speed on either channels...
United Kingdom
#17  
Doesn't the kangaroo use UART? Tony was using the PIC on the old V3 but I vaguely recall the V4 being able to support it.
United Kingdom
#18  
Rich is right the kangaroo uses the UART here is a video I did some time ago using it with the v4



Tony
#19  
Yes, the Roo attaches to any of three Uarts on the V4 ezb. You send simple serial commands for speed and position control. You can also get feedback information from the encoder or pot that must be attached to the Roo for the whole set up to work.
#20  
I stand corrected.... However, there is no pre written control in ARC to use with the Kangaroo.... You would have to write your own script to communicate with the kangaroo....
#21  
Has anyone written any scripts that would use sliders or pot inputs to then send the serial info to the Kangaroo or do I still have to write a script?
#23  
Thanks Toymaker, I'll check that program out.
#24  
@Toymaker, the Kangaroo does 4X quadrature decoding (using all four edge transitions). When doing 4X decoding, a line is a transition through all four edges -- four "counts". Encoders are generally specified either as counts per revolution or lines per revolution, though admittedly the former seems more common as it's a bigger number...

Basically, when rotating, it will read like this: A high, B high, A low, B low. (Or in the the opposite direction: A high, B low, A low, B high) 4X decoding uses all of these to improve resolution.

We've been looking for a while for a good Cortex M-based microcontroller with hardware quadrature decoding, as yes, the software-based quadrature decoding on Kangaroo can be a real limitation at higher speeds with high resolution encoders... Although, the best quadrature encoders we've used are actually capacitive with configurable resolution.