Our crab arm rover

[spacejunk]

@touretzky

@lewis

I’d been looking at gumstix as well and I’m interested to know what interface you are using to the wheel drivers.

Standard Lynx Motion solution: the wheels are driven by a Sabretooth 2x10 R/C motor controller, which gets commands from an SSC-32 (it looks like a pair of servos to the SSC-32). The SSC-32 gets commands from the gumstix over a serial line.

I still don’t get why people don’t just use serial to the sabertooth and not have the SSC-32.

[robotdude]

@spacejunk

I still don’t get why people don’t just use serial to the sabertooth and not have the SSC-32.

Because there is a version of the Sabertooth 2x10 that is only R/C. It’s a little cheaper, and for that reason people will use the Sabertooth with the SSC-32. If you’re not using servos, then sure the 2x10 for serial would make more sense. But if you’re using some servos on your bot, it may be better to plug up to a channel on the SSC-32.

[touretzky]

@spacejunk

I still don’t get why people don’t just use serial to the sabertooth and not have the SSC-32.

In addition to the motors, there are 10 HS-645MG servos on Regis, and we’re planning on adding some buttons and touch sensor too. So we need the SSC-32. And it’s more convenient to also control the Sabertooth through the SSC-32 than to run a second serial line into the Gumstix.

[kamen]

Excellent bot design, and I agree, too many bots have the cams where they wont do much good. Take the hexapods for example. The cam looks “natural” on the front end where a head would logically go, but be far more useful mounted on a scorpion style tail off the rear.

As for Regis, another segment on that crab arm and he could probably change his own tires! The ability for a bot to do mechanical maintenance on itself in the field (even if that field is your living room carpet) would be cool AND practical

[touretzky]

@Robot Dude

The replacement “stiffer” wheels are on order. I should have them in a week or so. They look the same as the ones you are using, but are so stiff they don’t even use foam inserts. Help is on the way.

I’ve been looking on the site for these, but no joy. Is there an updated ETA?

Will the new A4WD be using them?

[robotdude]

@touretzky

@Robot Dude

The replacement “stiffer” wheels are on order. I should have them in a week or so. They look the same as the ones you are using, but are so stiff they don’t even use foam inserts. Help is on the way.

I’ve been looking on the site for these, but no joy. Is there an updated ETA?

Will the new A4WD be using them?

I will be shipping the kits with the Proline Masher 2000 until I get stock of the better wheels. I do not know what is taking so long. I have had them on order for a long time, but still nothing.

[linuxguy]

@spacejunk

I still don’t get why people don’t just use serial to the sabertooth and not have the SSC-32.

Sometimes, a person (like me, for instance) is replacing continuous rotation servos with motors, and code is already written for direct control of two servo motors. The transition to using motors with a controller like the Sabertooth is much easier if it can be made to work with existing code first. In my case, it’s a matter of not wanting to immediately rewrite any code and to work with something I already know the behaviors of before getting into using the other modes the Sabertooth has.

It’s also a matter of needing both servos and motors on a robot. Servos to control sensor turrets, arms, grippers, etc, and motors for locomotion. Therefore, both the Sabertooth and SSC-32 would be needed.

8-Dale