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Nicodemus
01-20-2007, 05:06 PM
Ok I have searched through this forum and through the manuals but I still have a question about how to actually wire the gear-tooth sensor if someone could please send me a link for that or explain it to me I would be greatly appreciated. I have a feeling I know how it goes but last year I fried two and I'm just not sure.

Commander07
01-20-2007, 05:59 PM
What exactly is the Gear-tooth sensor used for?

Alan Anderson
01-20-2007, 06:08 PM
What exactly is the Gear-tooth sensor used for?
It's for detecting the passage of gear teeth past the sensor. Its output turns on and off in step with the metal teeth going by. When it is connected to a digital input on the Robot Controller, the software can set things up to count the pulses and thus tell how far the gear has turned in a given amount of time. It's useful for speed and/or position feedback on a motor.

Last year the TechnoKats used gear tooth sensors on the output of each gearbox for the drive wheels. In autonomous mode, that let the robot know how far it was traveling and how much it was turning, so it could control its motors to get to where it needed to be. I know a few teams used them to monitor and adjust the shooter wheel speed.

Phalanx
01-20-2007, 09:11 PM
Ok I have searched through this forum and through the manuals but I still have a question about how to actually wire the gear-tooth sensor if someone could please send me a link for that or explain it to me I would be greatly appreciated. I have a feeling I know how it goes but last year I fried two and I'm just not sure.

Everythng you need to know is in this thread......
http://www.chiefdelphi.com/forums/showthread.php?t=51840&page=2

First off, download and read Kevin Watsons encoder code and encoder FAQ
http://www.kevin.org/frc/encoder/
http://www.kevin.org/frc/frc_encoder.zip

To make his code work with the gear tooth sensors you need to remove the "Phase B" logic from it.

Second you wire them to digital I/O 1 and digital I/O 2 with a pwm cable. You also need to power them on a 12volt power supply as well.

See the 2007 Sensor Manual for more information.

To wire the sensor...

Take one end of a pwm cable, and solder it to J2, the black wire to GB (ground-black) the red wire to 5R (+5 volts-red) the white wire to SW (signal white). Connect the other end of this pwm to digital I/O 1.

Take a 2nd pwm cable and solder it to J1, the black wire to GB, the white wired to (12W), the red wire is unused. Connect the other end to a 20amp circut on one of your atc breaker panels.

Mount the sensor from .5 to 2.75 mm away from the gear to be measured.

Repeat this for the second one except connect it to digital I/O 2.

As for the code...
Use encoder 1 and encoder 2, disable the others. Then remove the "Phase B" logic in the interrupt handler for encoder 1 and encoder 2.

Nicodemus
01-21-2007, 02:19 AM
Thank you... though the code information and the such I don't need I'm just an electrical person anything doing with code goes right over my head I just know that our programmer wants a gear-tooth sensor working and I'm just trying not to fry it this year. Thank you again I really appreciate it.