First Innovation in Robotic
Sensors in Three
Terry Fritz — a Colorado-based
engineer and creator of award-winning robots — has
designed the first new
sensor to come on the
market for robotics in
several years. Mr. Fritz
calls the sensor
ThereminVision in honor of Leon
Thermin, who invented and patented a
musical instrument in 1919 that was played
by a musician’s hands moving near a pair of antennae.
Thereminvison II’s advantage over current technology
— infrared sensors — is that, with properly places
antennae, you can have a full 360° detection zone.The
principle of the sensor is based upon the fact that there is
a very weak electromagnetic field that surrounds an
antenna. When a conductor enters the electromagnetic
field, it changes the field’s capacity in a measurable way.
This conductor can be a hand or a metal object — such as
a robot. Almost all objects have some detectable
capacitance that changes the electromagnetic field.
ThereminVision II is an inexpensive kit that, when
assembled (requires soldering), allows experimenters and
robotics enthusiasts to detect when objects approach. The
output from the kit is wired to a microprocessor, which is
not supplied with the kit. The kit consists of four sensor
boards and a processor board. The sensor boards — when
placed at the four corners of a robot and connected to
antennae — form an electromagnetic field around the
robot that is a zone of detection for objects.
A microprocessor connects to the kit’s processor
board and polls the sensors. As an object approaches the
sensor’s antenna, it will send increasingly smaller bits to
the microprocessor. The antenna is not included, since the
kit builder needs to incorporate it into the design. Design
guidelines and sample programs are included in the
Features of the kit include:
• Four sensors. Each sensor weighs 3. 7 grams, draws far
less than 1 mA at 5 volts, and is less than 1 x 1.25 inches.
• The processor — a separate board — weighs 10. 7 grams,
at less than 1mA at 5 volts, and is 1.3 x 2.4 inches.
• There are two digital control lines and one output signal
line connected to a microprocessor which measures pulse
width. An optional control line turns the sensors off.
• Power can easily be drawn off the + 5 volts of most
• Detection range is proportional to the antenna and
object surface areas. See manual for details.
Programming could randomly move the robot until an
object is detected.
• A downloadable manual is available.
A demonstration robot and a kit can be seen at:
www.robotlandinc.com/tvision.htm The kit is $50.00
US (plus S & H).
A discussion group devoted to the Thereminvision II
kit is at : http://groups.yahoo.com/group/thereminvision/
For further information, please contact:
345 E. Camelback Rd.
Phoenix, AZ 85012
Circle #50 on the Reader Service Card.
Wireless PS2 Style
Includes: Hand Controller sixteen oz fighting robots
Receiver with built in:
Dual Motor Speed Control
Variable Weapon Control
Specializing in antweight robotic combat parts.
Circle #151 on the Reader Service Card.
SERVO 07.2004 39