Detecting Horizontal Movement

[Darrel Taylor]

Hi,

The only problem of that method is small errors ( < 1 LSB measurements for simple explanation ... ) are not taken into account and final result is then false.

Try this into an elevator ( or an automated train ) and I promise you will stay a moment in it calling for help ... !!!

Alain

Apparently, you didn't read the whole post.

[Acetronics2]

Hi, Darrel

you sure ??? ...

reminds me a thread about oversampling ... ( about altimeter ) that is a total view of mind for very small variations ( < 1LSB ) - like here !

Have a Happy new year.

Alain

[Darrel Taylor]

you sure ??? ...

Sure about what?
That "Integration" is a very usefull function used throughout electronics and computing.

Or that I could make a device that detects forward motion using accelerometers/gyros/and magnatometers.

In either case, YES!!!!

[Atom058]

Darrel - Thanks for that very nice example! I completely understand what you are trying to get across now. One last question... will this be sensitive enough to tell if you slooowwwwllllly coast to a stop?

Thank you to all of you who replied to this post! I hope everyone has a safe and happy New Year! Jeff

[Atom058]

Just did a quick look at Sparkfun for accelerometers and found that they have a bunch that look like they could easily be used with PICS. They have a nice comparison here:

http://www.sparkfun.com/tutorials/167

FYI - Jeff

[Darrel Taylor]

That depends on how slowly you coast, the resolution of the sensor, maximum speed and other factors.

You never really gave us an idea of what you are doing, other than moving over different surfaces, so I can't say.

[Atom058]

Darrel - Unfortunately, you just about know as much as I do. The person that wants me to do this is being pretty secretive. Here is a little more... I am assuming it is a motorized vehicle and the position of the wheels will not always be the same, so they can't be used for indication. This will be in an outside environment, moving over any type of surface from very smooth to rough (grass, dirt, pavement, snow, etc.) at a pace that can range from 1/2 normal walking speed and up. Ideally, they are looking for something that they can just aim at the ground and determine that it is moving. They are not concerned about speed or direction, just movement. Height of sensor can be about 3 feet. Oh yeah, and cheap (duh) ... I am leaning towards a vibration sensor, but I don't know enough about the end system to be able to say that it would be 100% reliable - I have not tossed out the accelerometer, thanks to you... So there you have it... And again, thank you for your input. It is appreciated! Jeff

[mackrackit]

At first I thought this was a "person carry" project.

I wish to detect my movement over ground

Mounting to a vehicle has more possibilities.
These a very nice units.
http://www.dickey-john.com/product/radar-ii/