Speed Sensors

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Posted by Warren Boudreaux.

Engineer on team #180, S.P.A.M., from South Fork & Martin County High School and UTC/Pratt&Whitney/NASA.

Posted on 5/10/2000 7:31 PM MST



Does anyone have any ideas on making a speed sensor?
I'm trying out some ideas for next year and need shaft speed input to the control.
I guess I really am a FIRST-aholic.....

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Posted by Jerry Eckert.

Engineer from Looking for a team in Raleigh, NC sponsored by .

Posted on 5/10/2000 11:05 PM MST


In Reply to: Speed Sensors posted by Warren Boudreaux on 5/10/2000 7:31 PM MST:



: Does anyone have any ideas on making a speed sensor?
: I'm trying out some ideas for next year and need shaft speed input to the control.
: I guess I really am a FIRST-aholic.....

Do you want any type of speed sensor, or one which is legal for competition?

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Posted by Warren Boudreaux.

Engineer on team #180, S.P.A.M., from South Fork & Martin County High School and UTC/Pratt&Whitney/NASA.

Posted on 5/11/2000 10:04 AM MST


In Reply to: Re: Speed Sensors posted by Jerry Eckert on 5/10/2000 11:05 PM MST:



Legal for competition.
: : Does anyone have any ideas on making a speed sensor?
: : I'm trying out some ideas for next year and need shaft speed input to the control.
: : I guess I really am a FIRST-aholic.....

: Do you want any type of speed sensor, or one which is legal for competition?

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Posted by Justin Stiltner.

Student on team #388, Epsilon, from Grundy High School and NASA, American Electric Power, Town of Grundy.

Posted on 5/29/2000 12:15 AM MST


In Reply to: Re: Speed Sensors posted by Warren Boudreaux on 5/11/2000 10:04 AM MST:



What about a magnet in the wheel and a reed switch close to the wheel on the 'fender' and have the Stamp count the # of times the reed switch is triggered in a given amount of time. Thus giving you your speed.

Justin Stiltner
Team #388
Epsilon
Grundy, Va

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Posted by Nate Custer.

Student on team #470, Steve Gregory, from Ypsilanti and Visteon.

Posted on 6/8/2000 4:49 AM MST


In Reply to: Re: Speed Sensors posted by Justin Stiltner on 5/29/2000 12:15 AM MST:



: What about a magnet in the wheel and a reed switch close to the wheel on the 'fender' and have the Stamp count the # of times the reed switch is triggered in a given amount of time. Thus giving you your speed.

We did something similur to this for our tower. It used a limit switch firing when ever a bolt on the shaft pressed it. With a bit of work, and some input from the motor we could also track position. Here is the code:

lift = lift + ( (p2_y / 128) & (RC_SW1 &~ contSwitch) ) - ( (~(p2_y / 128) & 1) & (RC_SW1 ''&~ contSwitch) ) &~ hook_down
lastLiftDir = p2_y / 128

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Posted by Jason Iannuzzi.

Engineer on team #11, Marauders, from Mt. Olive HS. and BASF, Rame Hart, CCM.

Posted on 5/12/2000 11:33 AM MST


In Reply to: Speed Sensors posted by Warren Boudreaux on 5/10/2000 7:31 PM MST:



Hmm...now you have me thinking.

You could probably use a cam on a shaft and one of the push button switches. Read the pulses when the cam triggers the switch, and work backwards to get your speed.

Or you are more interested in acceleration, you could probably make an accelerometer using either the potentiometers or the gyro..but that is FAR trickier..or at least it is in my head.

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Posted by Jerry Eckert.

Engineer from Looking for a team in Raleigh, NC sponsored by .

Posted on 5/12/2000 4:31 PM MST


In Reply to: Re: Speed Sensors posted by Jason Iannuzzi on 5/12/2000 11:33 AM MST:



: Hmm...now you have me thinking.

: You could probably use a cam on a shaft and one of the push button switches. Read the pulses when the cam triggers the switch, and work backwards to get your speed.

That solution might work for a shaft which is rotating very slowly; I can't imagine
it working at all on a drive train. Well, you could drop the speed of the cam with
a large gear ratio, but then the precision would be so low as to be virtually useless.

If only we had interrupts...

Jerry

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Posted by Nate Smith.

Other on team #66, GM Powertrain/Willow Run HS, from Eastern Michigan University and GM Powertrain.

Posted on 5/16/2000 11:16 AM MST


In Reply to: Speed Sensors posted by Warren Boudreaux on 5/10/2000 7:31 PM MST:



: Does anyone have any ideas on making a speed sensor?
: I'm trying out some ideas for next year and need shaft speed input to the control.
: I guess I really am a FIRST-aholic.....

You may not need to make one...while talking with the folks from Innovation First as they were packing things up down in Florida, it sounds like a few 'new sensors' may be in the works for next year...

Nate