Using CricketSats as an
Educational Tool in the
Science Classroom
Snowy Tree Cricket
Nature’s Temperature Sensor
• Natural oscillator
• Chirp rate affected by temperature
• Faster with increasing
temperature
• Why?
Find the Temperature
Cold
Hot
T(°F) = (# chirps per 13 seconds) + 40
Rate = Chirps per 13 seconds = T(°F) – 40
What’s a CricketSat?
• An electronic cricket
• Produces chirps, clicks or tones
relating to temperature
• Provides wireless balloon-borne
or ground-based measurements
• Entry level of NASA Student
Satellite Program
CricketSat Background
• CricketSat Origins
• Developed at Stanford
University
– Space Systems
Development Laboratory
• Part of the NASA student
satellite program
– Crawl, Walk, Run, Fly
– Teach fundamentals of
space hardware
development
– Space Grant Fellowship
Program
• Vermont Space Grant
Consortium (VSGC)
Student Satellite Programs
• CricketSat
– Lowest cost
– Real-time data collection
– Easily adaptable
• BalloonSat
– Recoverable payloads
– Larger instruments
• CanSat
– Dropped by parachute from plane
or rocket
– Test bed for CubeSat
• CubeSat
– Earth-orbit satellite
The HELiX/EPSCoR CricketSat Program
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HELiX / EPSCoR High School Outreach Program
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2003: Waldorf High School Charlotte,VT
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2004: Milton High School Milton, VT and JDOB High
School Boston, MA
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2005: Milton High School and Brattleboro High School
Brattleboro, VT
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2006: Long Trail School, Dorset, VT
University Collaboration
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Medgar Evers College, City University of New York
Awards
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2005: HELiX Symposium Poster Presentation, 1st
Place (Shared, Milton and JDOB schools, presenting
separate posters)
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2005: Massachusetts State Science Fair, 1st Place
(JDOB School)
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2006: HELiX Symposium Poster Presentation, 1st
Place
CricketSat Benefits
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Low cost (<$15)
Easy to assemble
Simple electronic operation
Provides live telemetry
Easy data collection methods
Adaptable for custom
applications
• Middle school through
college use
An Electronic Cricket
Radio
Transmitter
Oscillator
Temperature
Sensor
Oscillator Frequency vs
Temperature
CricketSat Sensor Circuit
• Oscillator frequency
determined by input
temperature
• Oscillator output signal
modulates RF carrier
frequency
Receiving Station
• Receiver extracts oscillator
frequency from input radio
signal
• Oscillator frequency output
may be measured by
stopwatches or instruments
• Calibration charts used to
determine temperature
Sensing the Temperature
Thermistor Device
• Resistance changes with
temperature as shown in the
graph
• Used in an electronic circuit
to vary the frequency of
oscillation
Thermistor
Temperature Sensitive Oscillator
• Produces an oscillation that
changes with temperature
• Oscillator frequency
determined by two resistors
and a capacitor
• Changes in temperature
affect the oscillator
frequency as shown in the
chart
Thermistor
Oscillator Demo
Thermistor
R1
555 Timer IC
Vcc
Output
LED
R2
Voltage on capacitor C1
Digital
Output
Signal
C1
Capacitor
Charge &
Discharge
Waveform
Time
Not Used
Simulation courtesy of Williamson Labs: http://www.williamson-labs.com
Oscillator Frequency Response to Temperature
• Oscillator Output Frequency
– Increases with warmer
temperatures
– Decreases with colder
temperatures
• Finding the Temperature
– A calibration graph, similar to the
one shown right, allows the
temperature to be determined
The Wireless Connection for
Remote Sensing
• The oscillator output frequency mixes (modulates) with
radio carrier frequency (RF) to provide a radio signal
• A radio receiver is used to recover the temperaturedependent oscillator signal
CricketSat Sensor Options
Resistive Sensors
Capacitive
Sensors
Other Sensor Types
Thermistor (temperature)
Humidity
Switch (activation, proximity)
Photocell (light)
Pressure
Reed Relay (activation, proximity)
Potentiometer (position)
Hall Effect (proximity)
Strain gage* (force, flex)
Infra Red (proximity)
DC Motor (rotation)
Connection to High School Curriculum
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Science Curriculum
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Earth Science (atmospheric studies)
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Environmental Science (soil studies)
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Physics/Chemistry (circuits, gas laws)
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Biology (wildlife studies)
Math Curriculum
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Data collection and graphing
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Linear and nonlinear relationships
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Determining line of “best fit” for a given set of data
Technology
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Wireless sensors and networks
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Remote sensing
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Computer-based data collection
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Excel compatible format
Skill Development
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Printed circuit board assembly
•
Soldering
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Testing and trouble-shooting
Teamwork
VT Framework and GEs
(VT Standards 7.1, 7.15, 7.18, 7.19, 1.17, 1.18, 1.20, 3.10; GEs S9-12: 2-8)
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Students demonstrate an understanding of the processes and change that occurs
over time within earth’s systems by using scientific methodology to measure, collect,
and analyze weather data for a particular location in order to make predictions of
future weather conditions.
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Students analyze and understand living and non-living systems as collections of
interrelated parts and interconnected systems.
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Students use technological engineering processes to design solutions to problems.
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Students interpret and communicate using mathematical, scientific, and technological
notation and representation.
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Students use graphs, charts, and other visual presentations to communicate data
accurately and appropriately.
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Students perform effectively on teams that set goals, conduct investigations, solve
problems, and create solutions.
Thanks!
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VITA-Learn
UVM HELiX/EPSCoR
Medgar Evers College
Milton High School
Vermont Space Grant
New York Space Grant