Gallaudet University Model Secondary School CricketSat User Guide Mike Fortney University of Vermont October 12, 2006

Electronic System Diagram CricketSat Wireless Sensor CricketSat Radio Receiver CricketSat Tone Decoder Audio Cable Temperature Sensor Speaker LED Sensor Selector

CricketSat Sensor CricketSat Wireless Sensor Temperature Sensor Electronic Cricket Electronic Cricket Produces periodic tone bursts (chirps) relating to temperature Produces periodic tone bursts (chirps) relating to temperature Chirp rate proportional to temperature above absolute zero Chirp rate proportional to temperature above absolute zero Chirps transmitted using radio signal allowing remote measurement Chirps transmitted using radio signal allowing remote measurement Up to 50-mile range Up to 50-mile range

CricketSat Sensor Detail Off On Power Switch Temperature Sensor Antennae Radio Transmitter Module Chirp-Tone Oscillator Chirp-Rate Oscillator 556 Dual Timer IC Battery Cable Light Emitting Diode (LED) Silicon rubber is used to reinforce components subject to damage from extensive handling 5-Volt Regulator

Temperature Conversion Chirp rate (frequency) is linearly proportional to temperature Chirp rate (frequency) is linearly proportional to temperature Counting chirps per minute is not accurate Counting chirps per minute is not accurate Chirps per hour is calculated from chirp interval (3600/Interval) Chirps per hour is calculated from chirp interval (3600/Interval) An linear equation is generated from the trend line An linear equation is generated from the trend line This graph based on chirp interval is most practical This graph based on chirp interval is most practical An accurate trend line is produced based on a prediction table using the linear equation from the left graph An accurate trend line is produced based on a prediction table using the linear equation from the left graph Three calibration points are shown to demonstrate the agreement Three calibration points are shown to demonstrate the agreement

CricketSat Receiver CricketSat Radio Receiver Amplitude modulation (AM) radio receiver ( MHz) Amplitude modulation (AM) radio receiver ( MHz) Produces chirp tone via a connected speaker or out the audio jack Produces chirp tone via a connected speaker or out the audio jack Range (using decoder) Range (using decoder) – 600 feet typical on ground – One to two miles by balloon Range (using speaker): miles by balloon Range (using speaker): miles by balloon

CricketSat Receiver Detail Off On Power Switch Antenna Radio Receiver Module Volume Control Audio Amplifier IC Battery Cable Light Emitting Diode (LED) Silicon rubber is used to reinforce components subject to damage from extensive handling Speaker Jack Audio Jack Audio Cable 5-Volt Regulator

CricketSat Tone Decoder Speaker LED Sensor Selector Ten-channel tone decoder Ten-channel tone decoder – Three channels available (2, 6, 10) – Temperature, Pressure and Humidity Ten-position DIP switch to select active channel Ten-position DIP switch to select active channel – Only one channel selectable at a time LED flashes and speaker produces proper tone when selected CricketSat sensor chirps LED flashes and speaker produces proper tone when selected CricketSat sensor chirps

CricketSat Decoder Detail Off On Power Switch Tone Decoder IC Battery Cable Light Emitting Diode (LED) Audio Jack Audio Cable Speaker Temperature (2) Pressure (6) Humidity (10) Future Sensor Selector Switch

CricketSat Sensor Test  Bend antenna wires to form a vertical “V” as shown in the initial diagram  Bend temperature sensor lead out to side of board, away from the residual heat of that thermal mass  Turn ON the sensor  See sensor detail diagram for switch operation  LED will remain OFF for nearly one minute  Should see LED flash briefly (~0.6 seconds) and repeat every 25 seconds or so at room temperature  Use the full page temperature conversion graph on the last page of this presentation to validate proper operation  Leave unit turned ON for the system test…

CricketSat Receiver Test  Straighten single antenna wire to point vertically from surface of circuit board  Turn ON the receiver circuit board  See receiver detail diagram for switch operation  LED will light and remain lit, flickering with activity  Adjust the volume control to the half-way point  If the speaker is connected, you will hear a hiss  You may hear other weather instruments that share this same radio frequency as well as other CricketSat sensors if they are enabled  The CricketSat decoder will only respond to pure tones produced by the selected sensor  You may remove the speaker if desired  Leave unit turned ON for the system test

CricketSat Decoder Test  On the red ten-position switch, make sure that the white lever switch (#2) for temperature is pressed down  All of the other nine switches must be in the upright position  Turn the unit ON  You should briefly see the LED flash and hear a tone from the built in speaker  The LED is very bright for outdoor use  Tilt the unit at an angle if it is too bright  Leave the unit turned ON for the system test

CricketSat System Test  Attach the free ends of the audio cable into the audio jacks on the receiver and decoder units as shown in the first diagram  Make sure that all three of the units are turned on  Make sure that the volume control is at a midway position  Sometimes too high will not work with sensor and receiver in close proximity  You should see the decoder respond to the sensor  Try placing the sensor outdoors or in the refrigerator/freezer to verify operation

Performing Measurements This version of the temperature sensor is not very sensitive This version of the temperature sensor is not very sensitive – Each tenth of a second represents >1˚C Measurements should be performed with a stopwatch good to hundredths of a second Measurements should be performed with a stopwatch good to hundredths of a second Practice measurements should be made with the sensor at a stable temperature striving for consistency Practice measurements should be made with the sensor at a stable temperature striving for consistency Performing the measurement once the decoder LED turns OFF may improve consistency by eliminating surprise by the ON event Performing the measurement once the decoder LED turns OFF may improve consistency by eliminating surprise by the ON event For the tethered balloon, allow sensor temperature to stabilize for a minute after moving to a new altitude For the tethered balloon, allow sensor temperature to stabilize for a minute after moving to a new altitude When placing the sensor in a drastically new environment, allow ten minutes for temperature to stabilize When placing the sensor in a drastically new environment, allow ten minutes for temperature to stabilize

CricketSat Flight System Balloon Balloon Parachute Parachute CricketSat sensor CricketSat sensor Or… Or… Tethered balloon- Tethered balloon- – No parachute

Gathering Atmospheric data Altitude: about 180 meters or 580 feet Stop every 30 m for 3 temp readings Altitude: about 180 meters or 580 feet Stop every 30 m for 3 temp readings

Roles & Responsibilities Balloon controller Balloon controller Altitude controller Altitude controller Angle reader Angle reader Data recorder Data recorder ‘Chirp’ interval timers (2) ‘Chirp’ interval timers (2) Calculator Calculator General observations General observations Overall Launch Operations Manager Overall Launch Operations Manager Balloon controller Balloon controller Altitude controller Altitude controller Angle reader Angle reader Data recorder Data recorder ‘Chirp’ interval timers (2) ‘Chirp’ interval timers (2) Calculator Calculator General observations General observations Overall Launch Operations Manager Overall Launch Operations Manager

Temperature Profile of the Atmosphere

Write a hypothesis What pattern will we see if we measure temperature every 6 meters up into the atmosphere? What pattern will we see if we measure temperature every 6 meters up into the atmosphere? Describe in words and a graph. Describe in words and a graph. What pattern will we see if we measure temperature every 6 meters up into the atmosphere? What pattern will we see if we measure temperature every 6 meters up into the atmosphere? Describe in words and a graph. Describe in words and a graph.

Temperature Conversion Graph

Flight System Materials CricketSat LP temperature sensor CricketSat LP temperature sensor 36” party balloon 36” party balloon – May be purchased already filled with helium – $10 filled, $3 not filled Model rocket parachute Model rocket parachute – Estes 18” or 24” – $ feet of cotton string 3 feet of cotton string 8” plastic tie wraps (qty 3) 8” plastic tie wraps (qty 3) 1” wide double sided adhesive foam (qty 2) 1” wide double sided adhesive foam (qty 2) – Cut to 2” length Helium if balloon is not filled at store Helium if balloon is not filled at store Miscellaneous Miscellaneous – Scissors

Attach Parachute to CricketSat Locate the four mounting holes on the CricketSat sensor Locate the four mounting holes on the CricketSat sensor CricketSat will be launched horizontally, upside down CricketSat will be launched horizontally, upside down Route a tie wrap through the two holes on each side, forming a loop Route a tie wrap through the two holes on each side, forming a loop Pull loops together and attach parachute strings Pull loops together and attach parachute strings

Attach Balloon to Parachute Place a small piece of tissue wadding in underside center of the parachute Place a small piece of tissue wadding in underside center of the parachute Tie one end of the string around this wadding for the parachute attachment Tie one end of the string around this wadding for the parachute attachment Tie the other end of the string to the balloon Tie the other end of the string to the balloon

Ground System Materials CricketSat or ham radio UHF receiver CricketSat or ham radio UHF receiver Attached CricketSat decoder Attached CricketSat decoder Stopwatch (interval delay) Stopwatch (interval delay) Watch (time) Watch (time) Paper and pen Paper and pen

Final Preparation Adjust CricketSat antennae to produce a 90 degree “V” Adjust CricketSat antennae to produce a 90 degree “V” Position temperature sensor to extend off the side of the circuit board, placing it in the airflow Position temperature sensor to extend off the side of the circuit board, placing it in the airflow If using a ham radio, tune it around 434 MHz to find the CricketSat signal If using a ham radio, tune it around 434 MHz to find the CricketSat signal

CricketSat Launch Take a few ground-based measurements before releasing Take a few ground-based measurements before releasing Release balloon Release balloon Record at each tone (or every other): Record at each tone (or every other): – Time of day – Interval delay – Estimated temperature (from temperature conversion graph)