Instructions Circuit Diagram

- 92 -
14.6. YETI Ultrasonic kit YT-ULT3
General Overview
The ultrasonic extension kit contains ultrasonic transmitter and receiver
modules. Ultrasonic waves are soundwaves at relatively high frequen-
cies, which cannot be heard by human ears.
Huntingbatshoweveruseultrasonicwavesfororientationwhiley-
ing in completely dark areas, avoiding all obstacles and catching their
preys. We call these ranging methods echoranging. Obstacles and
preysreectthesoundwavesandthebat’searsdetectthereected
waves.
YETI instead uses a microphone for sound detection.
The transmitter will emit acoustic impulses (wave bursts) with frequen-
ciesaround40.000Hz.Thereceiverwilldetectsignals,reectedby
nearby objects, and also the delay between transmission and reception
events.
The delay between transmitted and received impulses allows us to
calculatethedistancebetweentransmitter/receiverandreectionarea.
The ultrasonic module converts the delay period into an electronic
voltagelevelandaatcableconnectsthedelaysignaltoanA/D-con-
verter in the YETI processor, monitoring the voltage level.
A software module controls
the voltage monitoring and all
resulting robotic actions. We did
reservesufcientroominYETI’s
head to install the ultrasonic
modules.
The transmitter and receiver
each will be hidden behind
an “eyebrow”-hole in the
forehead.