Gallaudet UniversityGallaudet UniversityModel Secondary SchoolModel Secondary School CricketSat User Guide CricketSat User Guide

Mike Fortney Mike Fortney

University of VermontUniversity of Vermont

October 12, 2006October 12, 2006

Electronic System Electronic System DiagramDiagram

CricketSat Wireless Sensor

CricketSat Radio Receiver

CricketSat Tone Decoder

Audio Cable

Temperature Sensor

Speaker

LEDSensor Selector

CricketSat SensorCricketSat Sensor

CricketSat Wireless Sensor

Temperature Sensor

• Electronic CricketElectronic Cricket

• Produces periodic tone Produces periodic tone bursts (chirps) bursts (chirps) relating to temperaturerelating to temperature

• Chirp rate proportional Chirp rate proportional to temperature above to temperature above absolute zeroabsolute zero

• Chirps transmitted Chirps transmitted using radio signal using radio signal allowing remote allowing remote measurementmeasurement

• Up to 50-mile rangeUp to 50-mile range

CricketSat Sensor CricketSat Sensor DetailDetail

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 ConversionTemperature Conversion

• Chirp rate (frequency) is linearly Chirp rate (frequency) is linearly proportional to temperatureproportional to temperature

• Counting chirps per minute is not Counting chirps per minute is not accurateaccurate

• Chirps per hour is calculated from Chirps per hour is calculated from chirp interval (3600/Interval)chirp interval (3600/Interval)

• An linear equation is generated An linear equation is generated from the trend linefrom the trend line

• This graph based on chirp interval This graph based on chirp interval is most practicalis most practical

• An accurate trend line is produced An accurate trend line is produced based on a prediction table using based on a prediction table using the linear equation from the left the linear equation from the left graphgraph

• Three calibration points are shown Three calibration points are shown to demonstrate the agreementto demonstrate the agreement

CricketSat ReceiverCricketSat Receiver

CricketSat Radio Receiver

• Amplitude modulation Amplitude modulation (AM) radio receiver (AM) radio receiver (433.92 MHz) (433.92 MHz)

• Produces chirp tone Produces chirp tone via a connected via a connected speaker or out the speaker or out the audio jack audio jack

• Range (using Range (using decoder)decoder)– 600 feet typical on 600 feet typical on groundground

– One to two miles by One to two miles by balloonballoon

• Range (using Range (using speaker): 10-20 speaker): 10-20 miles by balloonmiles by balloon

CricketSat Receiver CricketSat Receiver DetailDetail

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 DecoderCricketSat Tone Decoder

CricketSat Tone Decoder

Speaker

LEDSensor Selector

• Ten-channel tone decoderTen-channel tone decoder– Three channels available Three channels available (2, 6, 10)(2, 6, 10)

– Temperature, Pressure and Temperature, Pressure and HumidityHumidity

• Ten-position DIP switch Ten-position DIP switch to select active channelto select active channel– Only one channel Only one channel selectable at a timeselectable at a time

• LED flashes and speaker LED flashes and speaker produces proper tone produces proper tone when selected CricketSat when selected CricketSat sensor chirps sensor chirps

CricketSat Decoder CricketSat Decoder DetailDetail

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 TestCricketSat Sensor Test

Bend antenna wires to form a vertical “V” Bend antenna wires to form a vertical “V” as shown in the initial diagramas shown in the initial diagram

Bend temperature sensor lead out to side of Bend temperature sensor lead out to side of board, away from the residual heat of that board, away from the residual heat of that thermal massthermal mass

Turn ON the sensorTurn ON the sensor See sensor detail diagram for switch operationSee sensor detail diagram for switch operation

LED will remain OFF for LED will remain OFF for nearly one minutenearly one minute Should see LED flash briefly (~0.6 seconds) Should see LED flash briefly (~0.6 seconds) and repeat every 25 seconds or so at room and repeat every 25 seconds or so at room temperaturetemperature

Use the full page temperature conversion Use the full page temperature conversion graph on the last page of this presentation graph on the last page of this presentation to validate proper operationto validate proper operation

Leave unit turned ON for the system test…Leave unit turned ON for the system test…

CricketSat Receiver CricketSat Receiver TestTest

Straighten single antenna wire to point Straighten single antenna wire to point vertically from surface of circuit boardvertically from surface of circuit board

Turn ON the receiver circuit boardTurn ON the receiver circuit board See receiver detail diagram for switch operationSee receiver detail diagram for switch operation

LED will light and remain lit, flickering with LED will light and remain lit, flickering with activity activity

Adjust the volume control to the half-way point Adjust the volume control to the half-way point If the speaker is connected, you will hear a If the speaker is connected, you will hear a hisshiss

You may hear other weather instruments that You may hear other weather instruments that share this same radio frequency as well as share this same radio frequency as well as other CricketSat sensors if they are enabledother CricketSat sensors if they are enabled The CricketSat decoder will only respond to pure The CricketSat decoder will only respond to pure tones produced by the selected sensortones produced by the selected sensor

You may remove the speaker if desiredYou may remove the speaker if desiredLeave unit turned ON for the system testLeave unit turned ON for the system test

CricketSat Decoder TestCricketSat Decoder TestOn the red ten-position switch, make On the red ten-position switch, make sure that the white lever switch (#2) sure that the white lever switch (#2) for temperature is pressed downfor temperature is pressed down

All of the other nine switches must be All of the other nine switches must be in the upright positionin the upright position

Turn the unit ONTurn the unit ONYou should briefly see the LED flash and You should briefly see the LED flash and hear a tone from the built in speaker hear a tone from the built in speaker The LED is very bright for outdoor useThe LED is very bright for outdoor useTilt the unit at an angle if it is too brightTilt the unit at an angle if it is too bright

Leave the unit turned ON for the system Leave the unit turned ON for the system testtest

CricketSat System TestCricketSat System TestAttach the free ends of the audio cable Attach the free ends of the audio cable into the audio jacks on the receiver into the audio jacks on the receiver and decoder units as shown in the first and decoder units as shown in the first diagramdiagram

Make sure that all three of the units Make sure that all three of the units are turned onare turned on

Make sure that the volume control is at Make sure that the volume control is at a midway positiona midway positionSometimes too high will not work with Sometimes too high will not work with sensor and receiver in close proximitysensor and receiver in close proximity

You should see the decoder respond to You should see the decoder respond to the sensorthe sensor

Try placing the sensor outdoors or in Try placing the sensor outdoors or in the refrigerator/freezer to verify the refrigerator/freezer to verify operationoperation

Performing MeasurementsPerforming Measurements• This version of the temperature sensor is not This version of the temperature sensor is not very sensitivevery sensitive– Each tenth of a second represents >1˚CEach tenth of a second represents >1˚C

• Measurements should be performed with a Measurements should be performed with a stopwatch good to hundredths of a secondstopwatch good to hundredths of a second

• Practice measurements should be made with the Practice measurements should be made with the sensor at a stable temperature striving for sensor at a stable temperature striving for consistencyconsistency

• Performing the measurement once the decoder LED Performing the measurement once the decoder LED turns OFF may improve consistency by turns OFF may improve consistency by eliminating surprise by the ON eventeliminating surprise by the ON event

• For the tethered balloon, allow sensor For the tethered balloon, allow sensor temperature to stabilize for a minute after temperature to stabilize for a minute after moving to a new altitudemoving to a new altitude

• When placing the sensor in a drastically new When placing the sensor in a drastically new environment, allow ten minutes for temperature environment, allow ten minutes for temperature to stabilizeto stabilize

CricketSat Flight CricketSat Flight SystemSystem

• BalloonBalloon

• ParachuteParachute

• CricketSat sensorCricketSat sensor

• Or…Or…

• Tethered balloon- Tethered balloon-

– No parachuteNo parachute

Gathering Atmospheric Gathering Atmospheric datadata

Gathering Atmospheric Gathering Atmospheric datadata

Altitude: about 180 meters or Altitude: about 180 meters or 580 feet580 feet

Stop every 30 m for 3 temp Stop every 30 m for 3 temp readings readings

Altitude: about 180 meters or Altitude: about 180 meters or 580 feet580 feet

Stop every 30 m for 3 temp Stop every 30 m for 3 temp readings readings

Roles & Roles & ResponsibilitiesResponsibilitiesRoles & Roles & ResponsibilitiesResponsibilities•Balloon controllerBalloon controller

•Altitude controllerAltitude controller

•Angle readerAngle reader

•Data recorderData recorder

•‘‘Chirp’ interval timers (2)Chirp’ interval timers (2)

•Calculator Calculator

•General observationsGeneral observations

•Overall Launch Operations Overall Launch Operations ManagerManager

•Balloon controllerBalloon controller

•Altitude controllerAltitude controller

•Angle readerAngle reader

•Data recorderData recorder

•‘‘Chirp’ interval timers (2)Chirp’ interval timers (2)

•Calculator Calculator

•General observationsGeneral observations

•Overall Launch Operations Overall Launch Operations ManagerManager

Temperature Profile of the Temperature Profile of the AtmosphereAtmosphere

Write a hypothesisWrite a hypothesisWrite a hypothesisWrite a hypothesis

•What pattern will we see if What pattern will we see if we measure temperature every we measure temperature every 6 meters up into the 6 meters up into the atmosphere?atmosphere?

•Describe in words and a Describe in words and a graph.graph.

•What pattern will we see if What pattern will we see if we measure temperature every we measure temperature every 6 meters up into the 6 meters up into the atmosphere?atmosphere?

•Describe in words and a Describe in words and a graph.graph.

Temperature Conversion Temperature Conversion GraphGraph

Flight System MaterialsFlight System Materials

• CricketSat LP CricketSat LP temperature sensortemperature sensor

• 36” party balloon36” party balloon– May be purchased May be purchased already filled with already filled with heliumhelium

– $10 filled, $3 not $10 filled, $3 not filledfilled

• Model rocket Model rocket parachuteparachute– Estes 18” or 24”Estes 18” or 24”– $6.50$6.50

• 3 feet of cotton 3 feet of cotton stringstring

• 8” plastic tie 8” plastic tie wraps (qty 3)wraps (qty 3)

• 1” wide double 1” wide double sided adhesive sided adhesive foam (qty 2) foam (qty 2) – Cut to 2” lengthCut to 2” length

• Helium if balloon Helium if balloon is not filled at is not filled at storestore

• MiscellaneousMiscellaneous– Scissors Scissors

Attach Parachute to Attach Parachute to CricketSatCricketSat

• Locate the four Locate the four mounting holes on mounting holes on the CricketSat the CricketSat sensorsensor

• CricketSat will be CricketSat will be launched launched horizontally, upside horizontally, upside downdown

• Route a tie wrap Route a tie wrap through the two through the two holes on each side, holes on each side, forming a loopforming a loop

• Pull loops together Pull loops together and attach parachute and attach parachute stringsstrings

Attach Balloon to Attach Balloon to ParachuteParachute

• Place a small piece Place a small piece of tissue wadding in of tissue wadding in underside center of underside center of the parachutethe parachute

• Tie one end of the Tie one end of the string around this string around this wadding for the wadding for the parachute attachmentparachute attachment

• Tie the other end of Tie the other end of the string to the the string to the balloonballoon

Ground System MaterialsGround System Materials

•CricketSat or ham radio UHF CricketSat or ham radio UHF receiverreceiver

•Attached CricketSat decoderAttached CricketSat decoder

•Stopwatch (interval delay)Stopwatch (interval delay)

•Watch (time)Watch (time)

•Paper and penPaper and pen

Final PreparationFinal Preparation

•Adjust CricketSat antennae to Adjust CricketSat antennae to produce a 90 degree “V”produce a 90 degree “V”

•Position temperature sensor Position temperature sensor to extend off the side of the to extend off the side of the circuit board, placing it in circuit board, placing it in the airflowthe airflow

•If using a ham radio, tune it If using a ham radio, tune it around 434 MHz to find the around 434 MHz to find the CricketSat signalCricketSat signal

CricketSat LaunchCricketSat Launch

•Take a few ground-based Take a few ground-based measurements before releasingmeasurements before releasing

•Release balloonRelease balloon

•Record at each tone (or every Record at each tone (or every other):other):– Time of dayTime of day– Interval delayInterval delay– Estimated temperature (from Estimated temperature (from temperature conversion graph)temperature conversion graph)