Herr Ball
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!
@Dave
Dimension Engineering 899 Moe Drive #21 Akron, OH 44310
@Herr, Thanks!
@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?
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
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.
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
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?
@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...