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Bill Chennault
12-07-2006, 08:19 AM
All--

My Memsic 2125 module arrived today! It is simply TOO EASY to use! In about a minute and a half I had it boarded up and sending numbers to Debug.

I was worried that such a device would not provide the sensitivity I needed for my application. Ha! I will have to throw most of the sensitivity AWAY! It is perfectly suited for what I want.

I am in the design process for an 8-legged walker with an articulated spine. It will have the same number of vertebra as a cat, but 8 of those vertebra will also serve as hips, which will be mounted on bearings on the 3/8" steel "spine." Therefore, when a leg is lifted--just like when you or I lift a leg--the center of mass deviates from the center of gravity. We compensate by leaning in the opposite direction. Most of this lean is accomplished with muscles in the leg and some of it is accomplished via the weight-bearing ankle. But, in any case, our inner-ear tells our brains what to do in the background.

My "inner-ear" will be the Memsic 2125. I will probably just use its raw output, because I really do not care about DEGREES, I just want to return the change to zero. This means pulling the center of mass back to coincide with the center of gravity . . . balance, in other words. The Memsic 2125 is, in my opinion, also easily accurate enough for a two-legged device to balance. To actually walk with a two-legged device, you·would probably need either two Memsic 2125s mounted perpendicularly to each other or possibly the triple axis version of the Memsic (I have not read its spec sheet, yet).

Get one. They are fun!

--Bill

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You are what you write.

geometrix
05-22-2007, 10:47 PM
Bill,

I am trying to interface a SignalQuest Inclinometer with a Parallax BS2px. I am a novice and I do not know how to parse the bytes from the inclinometer. In dual axis mode, the SignalQuest SQ-SI-360DA Solid State MEMS Inclinometer serial packet format is:

byte 2: X tilt (high byte, 16-bit unsigned integer)
byte 3: X tilt (low byte, 16-bit unsigned integer)
byte 4: Y tilt (high byte, 16-bit unsigned integer)
byte 5: Y tilt (low byte, 16-bit unsigned integer)

Do I use the GET command? How do I determine where each byte is located once I GET the byte. How can I get a stream of data from the inclinometer?

Thanks,
Neal

Chris Savage
05-22-2007, 10:57 PM
Neal,

GET is used to retrieve bytes from the Scratch Pad RAM. I would check to see what sort of communication your Inclinometer uses (most likely SPI or I2C). Perhaps starting a separate thread and providing a link to the datasheet might provide some more answers. Take care.

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Chris Savage
Parallax Tech Support

geometrix
05-22-2007, 10:59 PM
Thanks

Bill Chennault
05-22-2007, 11:44 PM
Neal--

What Chris said.

I am as new as you.

--Bill

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You are what you write.