For the ones that are keeping up with my saga:
> Hi,
>
> A couple months ago I bought a 3-axial gyro from ebay. I've looked
> everywhere for its datasheet and couldn't find any information. It is
> (was) manufactured by Northrop Corporation (see info below).
>
>
> NORTHROP CORPORATION
> FSC 51834
> Mfr. P/N: 50162-317
> 3 AXIS DC/DC GYRO PKG.
<snip>
I gave up on trying to find the datasheet for this part (long story),
therefore I started doing some tests this weekend using an oscope and a
bench power supply.
I was able to find the VCC and GND pins. As I mentioned before, all the
other pins output a kind of irregular periodical waveform that varies in the
following way when I increase voltage from 12VDC to 24VDC: amplitude
increases from +4/-4V to +8/-8V; wave period decreases from 2.15ms to 1.2ms.
When I measure each individual pin, there's no significant wave change when
I rotate the device its 3 axis, but if I measure two channels together in
X-Y mode (thanks Russel, I wouldn't try it by myself if not by your
suggestion), I was able to find the pins that are sensitive to each axis. It
is entertaining to turn the device on and off, it makes a noise similar to
jet engines starting or stopping. At 24V it stays warm to the touch, but no
smoke out of it.
It's like this: There are 10 pins, being that only 9 are connected. 2 of
them are for power, pins B-C are related to axis A (this is how axes are
labeled in the device), D-E are related to axis B and F-G are related to
axis C. I couldn't find out what pin K is for, its waveform is slightly
different from the other pins.
When I put a pair of pins on the oscope (X-Y mode) I see a diagonal of
increasing slope (0 deg phase shift?). If I spin the gyro about the axis
being measured, this diagonal line moves up or down on the other diagonal
(perpendicular to itself) depending on the direction I'm turning the device.
The displacement is proportional to the acceleration of the spin. I guess
that's why they call it a rate gyro? If I turn very slowly, the line
movement is almost imperceptible.
On the other hand, if I display both signals on time domain on ALT(ernate)
mode and turn the gyro, one waveform goes up and the other one goes down.
I'm not so experienced measuring things with oscopes, so I may be doing
something wrong (I have a 100MHz tek 465M).
So my question follows: how do I translate that type of signal to useful
digital values? (i.e. How many degrees turned on each axis)?
Cheers
Padu