Page 232 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

ball in a plastic enclosure. When tilted, the steel ball makes contact
with electrodes placed in the enclosure. Mercury switches may also
be used.
Electrolytic tilt sensors are expensive, but are excellent sensors. A
single electrolytic sensor can provide tilt information from two
axes. The hermetically sealed sensor has one center electrode sur-
rounded by four equidistance electrodes. As the electrolytic fluid
makes contact with the internal electrodes, the alternating current
(AC) resistance between the electrodes varies in proportion to the
degree of tilt.

Unfortunately, the electrolytic sensors cannot be read using a direct
current (DC) voltage source. This would cause the deposits to form
on the electrodes, rendering them useless. Instead an AC voltage of
approximately 3 V with a frequency of 1000 Hz is fed to the sensor.
The AC voltage from the center electrode is in proportion to the tilt
of the sensor.
If one were to use the electrolytic tilt sensor, I can suggest one way
to set up the information flow. Connect the AC output of the tilt
sensor to a bridge rectifier to obtain a DC equivalent voltage. The
DC voltage is fed to a voltage-controlled oscillator (VCO). The VCO 211
output frequency varies in proportion to the input voltage. The out-
put of the VCO is transmitted over a radio link to a receiver on
the motion platform. The receiver reads the frequency (tilt) and
activates a proportional control to tilt the platform.
Spectron, Inc., offers an integrated circuit, the SA40011, that sim-
plifies interfacing electrolytic tilt sensors. The DC output from the
SA40011 can be fed to a VCO as described before.
Again, implementing tilt to the operator is the difficult part of the
system. Proportional pneumatic or hydraulic systems can be em-
ployed to the seat to provide tilt.

Greater video range

The video range of our small transmitter is approximately 100 to
300 feet (ft). Obviously for longer distances another system needs
to be employed; it is called amateur television.
Amateur television (ATV) has been around for a number of years.
It’s been a method for radio amateurs to communicate via two-way
television. ATV had been the province of the elite radio hobbyist
due to the expensive cost of equipment. However, recent advances
in solid-state technology have changed that.
Team LRN Telepresence robot