Electronic Spirit Level
Robert W Murphree
SUBJECT: electronic inclinometer
from New Scientist 1 february 1992 p 26
ELECTRONICALLY INCLINED TO STAY ON THE LEVEL
Spirit levels, which since the 17nth century have trustily
ensured that surfaces are level, may soon be pushed out by
a microprocessor-contolled rival that can set a true
horizontal, a vertical or any angle in between, to one-tenth
of a degree.
The heart of the SMARTLEVEL, produced by Wedge Innovations
in San Jose, California, is a device called a liquid-filled
inclinometer. A sealed capsule contains two parallel conducting
discs with a space, partially filled with iquid between them.
... Any pair of parallel conductors acts as a store of electrical
charge. Its ability to store charge, its capacitance, is influenced
by what is between the conductors.
MY INFORMATION
ADDRRESS: Wedge Innovations
2040 Fortune Drive, Suite 102
San Jose, CA 95131
1-800-SMARTLEVEL(762-7853)
PRICE: 2 Ft. $120, 4 ft. $150
MY OPINION
Since this is a liquid device, you"re not going to get
millisecond sensing time, which would be nice if your
going to right yourself like a falling cat.
Also, it has to be reset if it gets jarred, a real
problem probably.
ADDITIONAL CITATIONS
J.M. CAMERON, R.c. Arkin, "Survival of falling robots,"
SPIE Proc Vol. 1613, 1992
John Nagle
> The heart of the SMARTLEVEL, produced by Wedge Innovations
>in San Jose, California, is a device called a liquid-filled
>inclinometer. A sealed capsule contains two parallel conducting
>discs with a space, partially filled with iquid between them.
Available at Orchard Supply Hardware.
This is not a new idea; ETAK has built two-axis versions of
such devices, packaged with a rate gyro, for their vehicle navigation
system. These were supposed to be cheap (I paid about $125 a few years
ago) and of modest accuracy, but I doubt they still make them.
But the technology is cheap, although there are tricks to getting it to
work well during violent motion.
John Nagle