Strong Vigor Gearboxes
Vigor makes the "Solarbotics" gearmotors, GM1, GM2, etc.
Their full line shown at http://www.vigorprecision.com.hk/index.files/BO.htm
I just received some samples of their BO26 module in an arm-breaking 1:371 gear ratio. Rated 6-12 volts, and pretty dang strong at 4.5 volts! The output is a through hole for a 3/8" hex shaft, so you can roll your own mechanical connection.·There's more backlash than I'd like, but a fellow (and also Holly) could quickly make a pretty·capable robot arm by simply connecting a few of these together, especially for the high-torque shoulder, elbow, and arm rotate joints. You could get by with smaller & lighter·gearboxes for the wrist and gripper.
These are just motorized gearboxes, not servos. No feedback encoders or pots, so those would have to be added, as well as the motor·drivers.
You could hack the guts out of a smaller servo, as Gramps showed. Or use a clever·4-state relay H-bridge...
Ken, would you·be interested in·selling these? I don't know if they're available in the US anywhere else. Very handy units, great for prototyping.
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·"If you build it, they will come."
Their full line shown at http://www.vigorprecision.com.hk/index.files/BO.htm
I just received some samples of their BO26 module in an arm-breaking 1:371 gear ratio. Rated 6-12 volts, and pretty dang strong at 4.5 volts! The output is a through hole for a 3/8" hex shaft, so you can roll your own mechanical connection.·There's more backlash than I'd like, but a fellow (and also Holly) could quickly make a pretty·capable robot arm by simply connecting a few of these together, especially for the high-torque shoulder, elbow, and arm rotate joints. You could get by with smaller & lighter·gearboxes for the wrist and gripper.
These are just motorized gearboxes, not servos. No feedback encoders or pots, so those would have to be added, as well as the motor·drivers.
You could hack the guts out of a smaller servo, as Gramps showed. Or use a clever·4-state relay H-bridge...
Ken, would you·be interested in·selling these? I don't know if they're available in the US anywhere else. Very handy units, great for prototyping.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·"If you build it, they will come."
520 x 200 - 12K
Comments
As an aside I really like some aspects of the Lego Servo motors as they are continuous rotation with quadrature encoders. The encoders have 360 counts per revolution which is really fine grained. Being continuous rotation you can couple them with reduction gearing for more torque. While they can be used with other micro controllers, most of their electronics are inside the NXT brick which reduces the attractiveness of this idea. Their shape doesn't help either.
So I've been thinking that a continuous rotation servo with a quadrature encoder built in would be really handy. But I don't think there's anything like that on the market. Hint Hint. I know all the pieces to do this are available (eg wheel watchers), but the result is more expensive and bulkier than an off the shelf product would be.