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Unread 01-03-2004, 00:44
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Re: Optical Sensors Used as Encoders?

Personally, I think unless the bot is very slow, the extra resolution wont matter. You still cant stop the bot theres just too much inertia. And we are not using the sensor on the actual wheel. We have it on a gear that is in a ratio of about 18:1 to the wheel. So that increases the resolution. And about the tape... The rules say "no adhesive-backed tape on the robot. The only exception is electrical tape, and it can only be used as as insulator". So a "decorative" explanation might not go over with the inspectors too well. White paint works very well, and is completely legal.
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Unread 01-03-2004, 07:59
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Re: Optical Sensors Used as Encoders?

We used Banner sensors last year for wheel encoders and have included them this year as well. We use a custom wheel so when the wheel was being assembled we just slipped a piece of dark papaer between the spokes of the wheel. By using two encoders (outlined above) you can tell direction and distance traveled. Last year we were able to get accurate down to at least an inch which made auto mode pretty easy. You need to couple the wheel sensors with a direction device to really know where you are.
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Unread 01-03-2004, 16:41
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Re: Optical Sensors Used as Encoders?

Last year we used banner sensors and tape marks, but this year we went ahead and spent a whopping $80 for shaft encoders (300 clicks per revolution ... as opposed to the 8 at best we had before).
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Unread 01-03-2004, 17:36
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Re: Optical Sensors Used as Encoders?

Quote:
Originally Posted by Greg
Personally, I think unless the bot is very slow, the extra resolution wont matter. You still cant stop the bot theres just too much inertia. And we are not using the sensor on the actual wheel. We have it on a gear that is in a ratio of about 18:1 to the wheel. So that increases the resolution. And about the tape... The rules say "no adhesive-backed tape on the robot. The only exception is electrical tape, and it can only be used as as insulator". So a "decorative" explanation might not go over with the inspectors too well. White paint works very well, and is completely legal.
I read all the First Questions and answers last night and they said that reflective tape for pulse generation is legal. As long as they don't change their minds like they did with the yaw rate sensors life will be good.
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