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Old 12-09-2002, 07:50 AM
BlueJeeper BlueJeeper is offline
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Join Date: Jul 2002
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Quote:
Originally posted by mrblaine
I read your stuff Rick and understand about 1/10 of 1% of it, but I have a question that you may have answered but that I did not understand.

Why wouldn't you use a body mounted dual axis digital inclinometer? I see that they are available from Digi-Key and wonder if that may slow down some of your program requirements?
mrblaine,

If you are talking about the Digi-Key clinometers I think you are, I actually considered those early on in my design. They were my first consideration but then I ran across the Analog Devices accellerometers.

Reasons for picking the ADXL202/210 are that they are much smaller, they are really low-power, and they have a greater range. Typically the dielectric-based clinometers have a smaller range (i.e. up to only about 45 degrees). The micromachined silicon ADXL202 has a much better resolution and range. The ADXL202 evaluation board is also more easily interfaced with simple microcontrollers like the Basic Stamp, which increases the likelyhood of success were a novice to try and reproduce my design for themselves (and it makes it easier on me). Aditionally, the Analog Devices accellerometers can also provide me with information beyond just tilt-sensing, which may prove useful to me later on.

Largely though, I picked the ADXL202 because I wanted to learn how to use it. I am somewhat certain that they are the same accellerometer (or at the very least, the same type of sensing technology) that Dean Kamen is using in the Segway Human Transporter ("IT"). This also makes me a bit more confident that I will be successful with them for the purposes of my project, since that technology may already be used in a transportation device for dynamic data acquisition.

Moreover I have some friends here in Champaign-Urbana who are also tinkering with this accellerometer and so it allows us to swap geek stories

I have not ruled out the use of the Digi-Key clinometers though, because as I said I really don't have a complete proof of concept yet for the use of ADXL202. I may move to a different sensor before the project is finished.
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