Hi All,

I am beginning a project for school in which I must interface a micro
(maybe a PIC, haven't decided yet ;-) to both accelerometers and piezo rate
gyros (its an autonomous helicopter project).

I need a little bit of help in interpreting the datasheets. First off, it
appears that most rate gyros give a constant DC output for a constant roll
rate, and the accels give a constant DC output for a constant acceleration.
Correct?

Secondly, aparently, for both gyros and accels., there is a large
manufacturing variation in the DC offset. So, I guess we are just supposed
to calibrate them to find out what the offset is and subtract it out? It
may seem obvious that this is the answer, but I found it strange that the
offset can sometimes be 500 times the DC level that would represent a
typical slow roll rate!

In addition, there seems to sometimes be a fairly sizeable tempco on the
output. How often does one need to compensate for this? In other words,
should I expect to have to include a thermistor in my circuit if I want to
detect,say, 0.1 g or 0.5 deg/sec roll rate? OR, should I be looking for
better gyros/accels that have a smaller tempco?

I am also,of course, open to suggestions on specific models to use.

Thanks very much,

Sean

|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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