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Topic: Sensor to detect movement and position (Read 381 times) previous topic - next topic

ScottG

I want to mount a sensor in an object that will lie flat most of the time.  But when it's picked up and moved I want to be able to detect that.  Just an accelerometer isn't good enough because I also need to know if it's flat and right-side-up.  An accelerometer will notice the object is moving, but when they put it down again, I need to know if it's flat and right-side-up.  This is going to be battery powered, so I need a low current solution.  Ideally, something that will sleep until there's movement.  Any suggestions?

Erdin

That is why an accelerometer is often used with a gyro.
The gyro drifts and the accelerometer is sensitive for vibrations and movement. Combine them both and you have a position in 3D space.
Combine them with a magnetometer (compass) and you have a steady heading.
Combine them with an absolute pressure sensor (barometer) and you have the height.

http://forum.arduino.cc/index.php?topic=58048.0

http://www.i2cdevlib.com/devices/mpu6050

http://www.ebay.com/sch/i.html?LH_BIN=1&_from=R40&_sacat=0&_nkw=mpu-6050+module&LH_PrefLoc=2&_sop=15


Grumpy_Mike

Yes you can tell which way up things are placed with an accelerometer, why do you think you can't.
The name is misleading, they are measuring the acceleration due to gravity and that always points in the same direction here on Earth.

jjspierx


I want to mount a sensor in an object that will lie flat most of the time.  But when it's picked up and moved I want to be able to detect that.  Just an accelerometer isn't good enough because I also need to know if it's flat and right-side-up.  An accelerometer will notice the object is moving, but when they put it down again, I need to know if it's flat and right-side-up.  This is going to be battery powered, so I need a low current solution.  Ideally, something that will sleep until there's movement.  Any suggestions?


An accelerometer will work to detect movement, and to detect the angle it is resting at.  The Z axis of the accelerometer should register the acceleration due to gravity while at rest and flat.  If the sensor is at an angle, the value of the Z axis will change.

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