Create a Tank bot?

Hi All,

Total ODrive newbie – just ordered one and a couple of these cheapo sensored motors.

I want to make a little tank robot – say something I can ride on over grass ( power wise, anyway – I don’t want to actually ride on it – just this much load ), and carry a camera system. Idea is “drive over cloud” carrying heavy things on grass and handle small hills. A “cloud-controlled tank wheelbarrow”, essentially.

I understand open loop steppers, but everything else is a mystery.

I have some really basic questions:

  1. These motors are outrunners, I think? Can I attach an encoder to the motor housing ( not the shaft ), and that will work? ( or will I just melt something? )

  2. Can I use the hall effect sensor in the motor along with an encoder at the same time?

  3. I saw Dexter ( the arm on hackaday ) and they had a crazy high count encoder designed ( 5 million p/r ). They claimed they could detect a cotton ball hitting an arm just by the position change at that resolution. Is it true? how can I build one ( I can’t find the emitter/receiver they used )? and can odrive handle high-count encoders like that?

Thanks in advance – I can’t wait for everything to arrive and to start playing with it…

Me too (in that I want a robo tank for running around outside). See pic of my tank under construction. I’m waiting on the drive motors to arrive to complete the track. Note, that’s a D6374 motor (huge) in the picture - shown just for reference size. Oh, and here is a link where you can get the tank tread links.

I’m planning to use the D5065 motors ODrive sells which will make this tank crazy! I’m using these motors cause it was just easiest being a known commodity with the ODrive. The plane is to use the CUI encoders with a 3D printed bracket to hold them on the back of the motor. And to answer your question, no - you can’t attach the encoder to the motor housing cause the housing spins. Hence the bracket. I can post some CAD if your interested.

To answer your second question, no - I think you either use an encoder or hall sensors. I say this cause they share the same input pins. In other words, the input pins are setup for either encoder or hall but not both at the same time (never mind having two sensor types fighting on the same pins). In my view, an encoder input is way better if you can afford the cost.

Good Luck,

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