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Subject: Re: Design of a circuit that can measure angle to the wall?
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Date: 01/23/03 at 10:21 AM
Posted by: Justin
In Reply to: Re: Design of a circuit that can measure angle to the wall? posted by Ray on 01/22/03 at 8:43 PM:
I need a measurement in degrees. To elaborate, the method using magnetics has a 2-axis magnet placed horizontally to measure rotation along the horizontal plane and a 1-axis magnet to measure tilt. Since tilt is always relative to the earth's gravity, it does not need to be calibrated. The 2-axis magnet returns voltage levels depending on absolute angle (I guess based on North Pole), which I use an A/D converter to determine the angle. Therefore, I point this device perpendicular to a wall and set this as my reference angle in software. If I shift my modules position to the wall by 15 degrees, the magnet will give me a new reading which indicates a 15 degree change horizontally.
As I stated before, this technique works well in good conditions, the components are relatively inexpensive (under $20), and the entire design is very small (5cm x 5cm). However, the performance is poor if there is a presence of other magnetic fields. Since I am integrating this with another circuit (that needs this information), I need a more robust solution that would be close in price and size, although size is less of an issue.
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