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More on sensors and motors

posted Jul 29, 2012, 7:22 PM by Gabriella Levine   [ updated Jul 29, 2012, 8:33 PM ]
Since we will have to have some sort of feedback on flexion and sail trim, I propose to try to look into waterproofing some rubber stretch sensors and attaching them like this below, alternatively, these 1 meter long stretch sensors can run the entire length of the boat on EITHER side to determine the boat's flexion. 

                     2012-07-29 18.49.38     

And for the motor, with the torque based on this boat winch's torque that wasnt quite enough
Worm gear: pressure angle 14.5 degrees I think
gear reduction just will be based on number of teeth on the spur gear, that we will mount a winch to.
 we want an output torque of about 20 kg-cm and 30-50 RPM. 

So, find a DC motor. Then find a worm gear to match its shaft. Then find a spur gear with the same pitch and the desired number of teeth for the gear reduction to be the desired RPM (DC motor's RPM / number of teeth), and the torque based on the gear reduction (DC motor's torque * number of teeth).

ie 24 tooth spur means the gear reduction will be 24  so
output RPM: motor's RPM / # teeth
and torque: motor's torque * # teeth

I like this but it is pricy, and I'm not sure if it has a worm gear driving it (I guess probably not because it doesnt say so in the documentation).