But it uses six potentially troublesome MG995 servos. Bill Henning's hexapod has had problems with those; I shared this dreadful review there: http://www.rcmodelreviews.com/mg995review.shtml
Most of the hobby motors are very high rpm very low torque. None of them will work for direct drive. The new robot motors that just came on the scene are all geared. Three different ratios from high speed to high torque. Include some mounting hardware and an aaa battery pack. On sale till mid July.
Jim
Most of the hobby motors are very high rpm very low torque. None of them will work for direct drive.
+1. You really need gearmotors to achieve anything noteworthy.
There are a few simple BEAM robots which use direct drive, basically two motor shafts driving on the ground. But limited speed and traction, plus the necessity for a flat smooth surface are real limiters, make the bot more of a functional novelty. This solar-powered Photopopper is "Capable of covering 1 meter in less than 2 minutes!"
@Loopy Byteloose, I placed an order to Pololu right after I read your reply. I got a pair of 120:1 motors with brackets and wheels. I also ordered a couple SN754410 IC's. As far as salvage goes I found a bargain for a 3-wheeled scooter because the seller says it won't take a charge. I really just want the motors and the wheels.
@Duane Degn, Lesson learned. Steppers have always been my preferred motor because they are simpler to program. They are essentially geared, digital motors. Controlling DC motors, IMO, is tougher.
I could hear the motors running at different speeds for the same pulse width. Being able to adjust how the robot tracks is key so road-testing is a 'must'.
@erco, I click on every link. Thanks. I studied the video showing you using relays to sync the wheels. It's got construction tips that I'll refer to. I still need to learn more about 'dynamic braking'. I'll have a better idea of what I need to do next week.
Comments
But it uses six potentially troublesome MG995 servos. Bill Henning's hexapod has had problems with those; I shared this dreadful review there: http://www.rcmodelreviews.com/mg995review.shtml
Edit: I found my fave gearmotors here: http://www.allelectronics.com/make-a-store/item/dcm-351/24-vdc-gear-motor-w/turntable/1.html
Jim
+1. You really need gearmotors to achieve anything noteworthy.
There are a few simple BEAM robots which use direct drive, basically two motor shafts driving on the ground. But limited speed and traction, plus the necessity for a flat smooth surface are real limiters, make the bot more of a functional novelty. This solar-powered Photopopper is "Capable of covering 1 meter in less than 2 minutes!"
http://www.robotshop.com/en/solarbotics-photopopper-kit.html
And the Shack sells this Velleman kit with direct drive: http://www.radioshack.com/product/index.jsp?productId=12476880
If you don't want to deal with 2nd hand industrial salvage, Parallax has a new geared motor with encoder that might be what you really want.
http://www.parallax.com/product/28819
http://www.ebay.com/itm/Maxon-DC-motor-145014-168043-Planet-Gear-With-Encoder-/290581364698?pt=LH_DefaultDomain_0&hash=item43a7ffbfda
@Duane Degn, Lesson learned. Steppers have always been my preferred motor because they are simpler to program. They are essentially geared, digital motors. Controlling DC motors, IMO, is tougher.
I could hear the motors running at different speeds for the same pulse width. Being able to adjust how the robot tracks is key so road-testing is a 'must'.
@erco, I click on every link. Thanks. I studied the video showing you using relays to sync the wheels. It's got construction tips that I'll refer to. I still need to learn more about 'dynamic braking'. I'll have a better idea of what I need to do next week.