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.
I forgot to mention the other method an engraved dot / white dot
Sometimes is not clear when you have pins in all the sides, if there is only one engraved or white dot that is the pin 1.
When you have two engraved dots in opposite corners, the thumb rule is the text orientation or the datasheet.
Hard to tell at this point. I have 4 of them that I am testing with. I really think the issue is garbage wire with poor connections going to the arduino that I am testing with. I get it to work sometimes and not others. I will hook up the oscope this evening and take a look at what I am getting from the board. I will probably solder wire onto the arduino that I know is good and punch it down into the breadboard. It seems like this would eliminate this possibility.
Thank you ptp. I have worked with pc chips in the past, and some when I used to repair arcade equipment (about 25 years ago). I just had not run into this config before and it confused me a bit.
I think the logical thing to do is go back to just one of them to see if I can get it to work reliably. Switching out between 4 of them is an easy way to get confused as to which one is sometimes working and which one is not working at all. Ill put some time into this this evening and see what I can figure out.
@David
Regarding the Kangaroo limits i think is related to the Kangaroo micro controller max frequency, the same issue like Arduino.
So if the limit is a frequency, to calculate the max frequency of one Quadrature Encoder (Hz) is:
Speed (Revs Per second) x Encoder PPR x 2 channels x 2 (rising / failing)
regarding your calculations, where is the speed ?
40 rpm
I took a break for "Lunch" and wired a much better set of wires to the arduino. It looks to be working now. I will have to do some testing this evening to make sure that the counts out of the circuit are indeed half of what the encoder reports without the circuit.
Thanks for all of the help along the way to all.
David
Another thought as to the limit is the limit to the size of the variable that is used. For example, int in their code (depending on what they are using) has a specific size. If they are taking 2 int's and comparing them, that would be a different size. I assume their controller is a 16 Mhz controller but I dont know. I will have to go see what I can find, but the code could also be limiting the counter.
I suspect that it is an issue with the type of variable that they are using, because even a 2Mhz controller should be able to keep up. I am nowhere near 2 million clock cycles.