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Unread 07-02-2008, 21:59
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Phalanx Phalanx is offline
Formerly Team 1089 (Mercury)
AKA: Michael Reffler
FRC #5431 (Titan Robotics)
Team Role: Mentor
 
Join Date: Jun 2005
Rookie Year: 1999
Location: Lewisville, TX (previously NJ)
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Re: What's the best ultrasonic?

Quote:
Originally Posted by Nathan View Post
Sometimes when we have the sensor hooked up and are reading the value in the terminal window the value will go insanely high, and then when we rotate the sensor the insane value returns to a normal value. By "insane value" I mean it jumps from around 13 to 213.
Nathan
We've used them and they work well.
A few things I have found with them in order of significance....

1) On "power-up" they need a large, clear, wide and obstacle free area for self calibration to work well, if they don't calibrate well you will get odd readings.

2) They don't respond well to rapid large change in distance. For example, it's reading an object 10ft away, you put your hand in front of it and quickly remove it, it will take a few cycles to recover from that. Use an averaging routine or similar logic to get several readings before acting.

3) Isolate them from vibrations as much as possible, vibrations will get picked up and misinterpreted.

4) Use RF shielded cabling to eliminate other noise.
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Last edited by Phalanx : 07-02-2008 at 22:02.