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.
so full power (12V) each motor has 38K ticks per second ?
powerful combination gears encoders
ok talk tomorrow !
Yep 38k per second per motor.
I spoke too soon on the flip flop. It ran for a few seconds then stopped reporting. The consistent number was because it quit reading. I was reading total ticks instead of the ticks per second.
Without the flip flop it looks like it was working fine. I will look at it more tomorrow. I suspect that the flip flop is a slower one that can't keep up and gives up. I will hook it back up and check it out tomorrow again. I may have to get some different IC's that run at higher speeds. Tony mentioned some earlier that ran at about 14 Mhz at 5v. I think these are running at about 5 Mhz.
http://www.ti.com/lit/ds/symlink/sn74hc74.pdf
I have decided to order some of these to eliminate the concern about the speed of the chip. I suppose that they will be able to run at 30 Mhz at 5v. This will quit being a concern at that point and I can focus on the circuit. I will do more testing this evening on the current chip to see if running at a slower speed allows the flip flop to work. I will let you know how it turns out.
David, HC (logic) can go up to 50MHz but as I said in the earlier post watch the pin-out as from memory it is different from the 4013.
Good Luck!
Tony
Thanks Tony, I had to stop the student who is helping and send him the new datasheet. He had just completed the schematic but had not done much on the board layout. Basically this chip has the same pins, but in different locations. I will be building another breadboard for this chip to get the pinouts correct.
I also will be interested in seeing if my theory is correct on the 4013 by running the motor much slower. I find it interesting that it picked up values for 2 seconds and then stopped working. I think I flooded it and it stopped taking data. This would make sense to me but I could be totally off. Will know more about the 4013 chip this evening and will update.
Thanks for all of your help.
Yes, the 74HC74 is an identical D-Type flip-flop just a diff logic family, with a different pin-out.
I am confused about the 4013 partially working, I would have expected it to work, I am sure you will sort it though and find out what is going on!
Tony