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Unread 14-03-2013, 22:07
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Measuring RPM for a Free-Spinning CIM

Hey
How can i measure the RPM of our shooter CIM if the CIM is not connected to a gearbox.
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Unread 14-03-2013, 22:16
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Re: Measuring RPM for a Free-Spinning CIM

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Originally Posted by 2185Bilal View Post
Hey
How can i measure the RPM of our shooter CIM if the CIM is not connected to a gearbox.
Many teams make their own home-brew one-count-per-rev optical or magnetic sensor. A sensor like that is excellent for shooter wheel speeds, if decoded properly.

Optical: Paint half the wheel white and the other half black, and sense it with a photosensor.

Magnetic: put a pair of magnets on the wheel, 180 degrees apart, and sense it with a latching Hall sensor (US1881 works well)

There are many other configurations.



Last edited by Ether : 14-03-2013 at 22:22.
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Unread 14-03-2013, 22:19
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Re: Measuring RPM for a Free-Spinning CIM

Our team used the light sensors from 2011 and programmed a tachometer to output to the DS. By putting a piece of electrical tape on a wheel, we were able to use this as a "tick" mark in programming. Review team 358's example under Tachometer for sample code. If you are interested in this, message me and I'll help you get it set up.
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Unread 14-03-2013, 22:48
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Re: Measuring RPM for a Free-Spinning CIM

We used a photo sensor and a piece of retro reflective tape that is pretty darn accurate, we have it so that we don't shoot in autonomous until it speeds up, then when it senses a sudden drop it waits until it speeds up again, then coasts down when it senses the next Frisbee. It also lets us detect jams, and stop the motor to prevent fried motors.
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Unread 14-03-2013, 23:00
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Re: Measuring RPM for a Free-Spinning CIM

where can i get a photo sensor
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Unread 14-03-2013, 23:02
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Re: Measuring RPM for a Free-Spinning CIM

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Originally Posted by 2185Bilal View Post
where can i get a photo sensor
read post #3


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