Darathian
Resolved by Dunning-Kruger!
Since I know some of you have used the Sabertooth and Kangaroo I figured I would ask opinions.
I have decided on the Parralax Arlo base for my next robot chassis. I will use the caster's from parralax.
I will most likely be using the Sabertooth and kangaroo combination for motor controller/PID but I am not decided on this and open to suggestions.
I also find myself in a heated mental debate between the wheel/motor combination from parralax or the Zagros Rex motors and wheels combined with the Sabertooth/Kangaroo.
Item 1:
One of the key items for me is how well the encoders between the two different motor/wheel sets works with the Sabertooth and kangaroo.
Item 2:
The other item floating in my mind is the ground clearance between the two motor/wheel sets. It seems at least to me that the Zagros wheels would provide more ground clearing but since the base plate of the chassis provides stability to the base platform I am not really sure if using the Zagros motors are feasible.
Item 3:
Since I am going to build a body, arms and head on top of the base the torque and weight carrying ability is important.
Item 4:
I need to be able to control both the position and speed of the motors at the same time. For example example I should be able to have to robot move lets say 1 feet at a certain speed.
I know this is kind of an open ended questions but if anyone have used any of these wheel/motor combinations please provide your 2 cents as it relates to the items listed above.
I appreciate any comments or insights you guys can provide.
Just finished making these. I will test them out tomorrow to make sure they all work. I'll send those that sent me an email an invoice through paypal this weekend.
Just finished testing every one of these individually. With 12.8 V to the motor I get right around 24K ticks per second. This should put these at about 32K per revolution which is correct. I will send invoices later today and will be shipping these on Tuesday. American holiday prevents me from mailing these out on Monday. I am including your basic pins with these and these pins will not be soldered to the board.
Thanks for your patience. BTW, there are 22 available for sale if anyone needs these in the future.
Invoices have been sent on domestic orders. I will need to go to the UPS store for international orders which I will do tomorrow. I will be sending all of these out tomorrow.
Total cost for domestic with 2 day shipping is $22.80 for 2 of them. I have 4 more built, tested and ready to ship if anyone would like them. The others after this will be built and tested as ordered, but all of the components are here so it wont take much time at all to fulfill an order.
Thanks David
Money sent.
Thanks for doing this for us David.
The funny thing is that a week ago at the Dallas Personal Robotics Group meeting, there was a group of people discussing this same issue but with an Arduino controller and a different motor. They were looking for a way to reliably reduce the counts per rev on a motor due to the encoder being behind the gearing in the motor. I told them some programming solutions like just catching the rise and discarding the drop on each of the encoders and such. They didn't like this solution so I then said that you could use a flip flop type solution. They said that they didn't want to add other IC's to the robot that someone would have to design and build.
They are trying to come up with a basic robot platform that would be expandable and allow a novice to learn about robotics and compete in a competition that they have coming up. This is when I mentioned EZ-Robot to them and described the EZ-B and ARC to them. I don't think that they believed me about ARC and how easy it would be to build what they were designing. Anyway... next time I am down there, I will demonstrate it to them and also bring some built flip flop circuits down to them to use/buy. It always amazes me when I talk to expert robot builders about how simple things can be and they seem to discount it because it is easy. I thought that was the entire point of what they wanted to do, but I was new among them so there is no level of trust built yet for them to believe what I am saying, and I get that.
Cochran Robotics online store is now, well, Online... Anyone needing these in the future can order from CochranRobotics.com. I am now finished posting on this thread
Thanks David
Zagros is having issues keeping the motors in stock now. This is an issue for me...
I am in discussions with GLOBE to be a distributor for these motors now. I should have a quote in a couple of days for a purchase that will allow you to get these motors/encoders from me. I have asked for 2 different products to be quoted. One will use the Avago 500 count encoder and the other will use the Avago 256 count encoder. The 256 count encoder on these motors is not an existing part number at GLOBE meaning that they would probably cost me more, but we will see. The 500 count encoder on these motors is an existing part number and is what is sold by Zagros when in stock. It is also the one that requires the use of the logic divide by 2 boards for sale on my website to allow it to work with a DE Kangaroo controller. I should have news in the next couple of days and will update here if I will be able to carry these motors or not.
I can sell these motors for about $200 each. This leaves me only about $20 profit. These would have 256 count encoders and would eliminate the need for the divide by 2 circuit. If you would be interested in doing this, please email me. My email is on my profile. This gives 32,512 ticks per rotation. With a 4 inch wheel, this gives you about .01 mm accuracy.
Thanks