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Electronics => Electronics => Topic started by: zhangzongyang1990 on September 10, 2011, 09:40:30 AM

Title: The Use of Accelerometer
Post by: zhangzongyang1990 on September 10, 2011, 09:40:30 AM
Hi,

I have a very basic question about using accelerometer. If it's a z-axis accelerometer, can I use it for other axes?
For example, http://sg.element14.com/freescale-semiconductor/mma1260eg/ic-sensor-accel-z-axis-50g-soic16/dp/1457136 (http://sg.element14.com/freescale-semiconductor/mma1260eg/ic-sensor-accel-z-axis-50g-soic16/dp/1457136)

I'm not very clear if there is any fundamental difference between x-axis and z-axis accelerometer.

Please pardon my ignorance because I'm new. Thanks a lot!


Title: Re: The Use of Accelerometer
Post by: 123laurens on September 10, 2011, 09:48:35 AM
Z axis means up or down, so if the chip goes up, it senses it. but not if it goes sideways. if you want it to work sideways, tilt the board sideways so the sensors top is facing the direction you want to sense.
Title: Re: The Use of Accelerometer
Post by: zhangzongyang1990 on September 10, 2011, 09:28:55 PM
Thanks a lot!  ;)
So it's called z-axis because when it's mounted in up and down direction, it senses z-axis acceleration. Yet I can still use it for any direction. Right?
Title: Re: The Use of Accelerometer
Post by: klims on September 13, 2011, 11:40:46 PM
Maybe this will help (http://a3.mzstatic.com/us/r1000/032/Purple/90/32/8d/mzl.jwhtzrnl.320x480-75.jpg)

These axes only relate to the chip. In the picture the y axis is up, but if you were to lay the chip in the picture down z axis would be up. You can mount the chip however you want to get the acceleration in the axis you want. I'm not 100% sure, but I feel like if you were using the accelerometer as a tilt sensor then you might run into some problems.

Not sure if you know this, but most accelerometers like this one (http://www.siphec.com/item/MMA7260Q-uMod-U.html) have notations on the PCB to show you the +- direction of the axis. In the picture it's pretty easy to see x/y +-, but z+ is into the page. The way I know this is by imagining an arrow with a tail on the back, then imagining what it would look like from the front or the back of the arrow. When looking at the back of the arrow it's draws with the tail(feathers) on it, but when draws from the front it is drawn like a dot, showing just the head of the arrow.
Hope this helps.
Title: Re: The Use of Accelerometer
Post by: zhangzongyang1990 on September 14, 2011, 08:03:32 PM
Maybe this will help (http://a3.mzstatic.com/us/r1000/032/Purple/90/32/8d/mzl.jwhtzrnl.320x480-75.jpg)

 I'm not 100% sure, but I feel like if you were using the accelerometer as a tilt sensor then you might run into some problems.


Thanks a lot!

What kind of problems you think I might run into?