Follow up Design Review

The University of Northern Colorado

GoGreenSAT

Jessica Gage, Max Woods, Brent Hill, Ryan Marshall, Zach Sears

Mar. 27 2009

IndexSection Slide NumberMission Overview 3Mission Requirements 4Fundimental Block Diagram 5Concept of Operations 6Structual Drawings 7Structual Drawings 8Structure** 9Schematic* 10Parts List* 11Subsystem Overview* 12Subsystems-Peltier Cooler** 13Subsystems-Pendulum** 14Test Plans 15Cold Test Results** 16Cold Test Results** 17Cold Test Results** 18Management 19Conclusion 20Appendix A-Calculations: Impact Test** 21Appendix B-Weight Breakdown** 22Appendix C-Box Dimensions** 23

*Change from original CDR, **New since original CDR

Mission Overview The goal of GoGreen SAT is to observe the

most effective materials and conditions in which a payload can generate energy to be used and stored.

GoGreen SAT will determine the maximum energy output of different onboard systems throughout the flight.

The three energy systems are: Pendulum: Capturing the swinging motion of

the flight line Solar Power: Capturing energy from the sun Peltier Cooler: Using the differences in

temperature inside and outside the box to produce energy

Mission Requirements

Green: Compliant, Yellow: Partially Compliant, Red: Not Compliant

Requirement Method Status

The payload must not exceed a weight of 1.5 kg. Design, Test

The flight line should go through the payload's center of gravity. Design, Analysis

The payload must be able to survive an impact of at least 16m/s. Design, Test, Analysis

Components in payload must be able to survive a temperture of -80˚C. Design, Test

Payload must not "cut" through the flight line. Design, Test

Payload must survive the "shaking" of balloon burst. Design, Test

Fundamental Block Diagram

Concept of Operations

Before the launch of the balloon, the payload will be activated via an external switch to provide power to the Logmatic recording software.

During the ascent, the software will gather current readings from the solar panels, the Peltier cooler, and the pendulum system. At a rate of 100 data points per second.

The solar cells will gather light energy from the sun depending on the payload’s orientation (an increase in altitude is expected to produce an increase in energy output).

The Peltier cooler will produce a current as the outside of the payload is cooled by decreasing atmospheric temperatures, and the inside of the payload maintains a reasonably warmer climate.

The pendulum system is expected to produce a current as the turbulence of the payload causes the pendulum to swing the attached magnet over a series of six copper coils.

After payload recovery the SD card will be taken out of the data logger and the flight data will be dumped into excel. The data will be calibrated.

Structural Drawings

Copper Coils on Board

Side View of Box, Solar Panels on Top

Pendulum

Structural Drawings

Battery

Hobo, Barometer

Logomatic Hot Hands

Peltier Cooler

Copper Plate

Pendulum

Copper Coil

Back View of Box

Top View of Box

Side View of Box

Structure The box will be made out of ½ inch foam

core board which will be cut to the correct dimensions.

The box will be held together with hot glue.

The box will be reinforced with additional foam core board inside.

The outside of the box will be painted black to help absorb the heat from the sun.

PVC pipe will run through the middle of the box for the flight line to go through.

The pipe will be attached to the box using ball bearings.

Schematic

StartSw

Barometer

CurrentSensor

CurrentSensor

CurrentSensor

PeltierCooler

SolarPa2

SolarPa1

D1DIODE

L6100 coils

L5100 coils

L4100 coils

L3100 coils

L2100 coils

L1100 coils

87654321

CP1CP2

DataSeq

Logomat

+ V17V

*There will be resistors added to pull the created power

*The grounds will go to the ground on the Logomatic

Parts List

Parts Company Model

Solar Panels Flex Solar Cells, OEM Components RC 7.2-75

Peltier Cooler Frozen CPU 437W

Magnet K&J Magnetics, Inc. DX0X0-N52

Low Current Sensor Sparkfun Electronics ACS712

SD Card

Logomatic Sparkfun Electronics V1.0

Ball Bearings McMaster-Carr 57155K356

Copper Sheet Whimsie 21-gauge

Foam Core Board Hobby Lobby 1/2"

Lithium Battery 7V

Subsystem Overview Power for the payload will come from a 7V

battery. Data from the flight will be stored at a rate

of 100 points per seconds in a SD card. The payload will have two states, non-

active and active. A protected switch will be installed on the outside of the box to activate the payload.

Peltier Cooler-there must be a temperature difference between the two plates.

The inner components (Hobo, battery, logomatic, and SD card) should not get below negative 20˚C.

Pendulum-Must swing in only one dimension.

Subsystems-Peltier Cooler

Peltier Cooler- If you apply a voltage to a thermocouple it causes a temperature difference between the two plates.

The Seebeck Effect- If two different metals are connected at two different locations and there is a temperature difference between the two junctions a voltage will be created.

The peltier cooler will be used to create the Seebeck effect and produce a voltage by creating a temperature difference between the plates.

The peltier cooler will be integrated into the box so one side faces out of the box and the other inside.

There will be a copper sheet on the outside of the box to cool that face of the peltier cooler more efficiently.

Hot Hands will be used to heat the other side of the peltier more efficiently inside the box.

*http://www.heatsink-guide.com/peltier.htm

Subsystems-Pendulum

The pendulum system will use magnetic induction to create power.

A magnet will be placed on the end of the pendulum.

The pendulum will swing back and forth over six copper coils.

The swinging motion of the balloon flight line will drive the pendulum.

Test Plans

Cold Test- Dry Ice/Liquid Nitrogen, Styrofoam cooler, four thermo probes, four multimeters, timer

Impact Test- high place to drop box from

Shake Test- Line/string Time Test- Timer Flight Simulation Test- Time and Cold

test combined with all components running/storing data

Cold Test Results

Cold Test #1 and #2: The box was suspendered inside a cooler where dry ice was placed. This test was done to see how well a box inside the main box would insulate the electrical components. The dry ice did not cool the box enough and an additional test had to be run.

Cold Test Results

Cold Test 3: The box was suspended inside a cooler with liquid nitrogen in the bottom of it . The liquid nitrogen cooled the box past the predicted low temperature of the flight. Another test will be run at a later date when all of the components are working.

Cold Test Results

Peltier Cooler Cold Test #1: This test was run during cold test #3. The results from this test showed that there needed to be a way to stop the peltier cooler from pulling voltage from the system.

Impact Test Results A test box was constructed of the same size and relatively

the same weight as the flight box to use for the impact test. This was done as to not damage any actual flight components

before flight. During actual flight impact the two pieces that need to

survive are the Logomatic and SD card. The test box was dropped of a stair well at different heights. The impact speed from past flights was calculated to be

between 10mph-35mph (4.5m/s-15.5m/s).

Flight of Stairs Impact speed(m/s) Damage done to Box

1 7.7 none

2 10.8 none

3 13.3 slight dent

4 15.3 slight dent

5 17.1 slight dent

Management

Program Manager-Jessica Project Members-Max, Brent, Ryan,

Zach Faculty- Dr. Bob Walch

Meetings, Tue. 6:00 p.m. and Thus. 7:00 p.m. and scheduled as needed

Budget-$800-$900

Conclusion

Issues/Concerns: The magnet used in the pendulum system will

interfere with other components in the box. The current produced by the pendulum system

will be to little to measure at times. The temperature difference between the two

plates of the peltier cooler will “flip-flop” during the descent, which will pull energy instead of produce it. This problem could solved with a diode.

The box will continue to swing in one direction for extended amounts of time, causing the pendulum not to move much.

This data from this payload should allow the efficiency of each system to be analyzed during the different sections of the flight.

Appendix ACalculations: Impact Test

vf^2=vi^2+2ghvf=sqrt(vi^2+2gh)

vf=2gh

vi=initial velocity=0 m/s g=9.79m/s

vf=impact speedh=drop height

Appendix BWeight Breakdown

Item Weight (kg)Center Rod .019 Peltier Cooler 0.056Copper Sheet 0.3Box Frame 0.315Magnet 0.096Coils and Base 0.217Pendulum 0.03Solar Cells 0.012Batteries 0.12Inner Box 0.086Ball Bearings Hot Hand Pack Bearings for Rod Total Payload Weight 1.165

*Estimated Total Weight=1.4kg

Appendix CBox Dimensions

14”

7”

7”

7”

14”

20.5”

20.5” 20.5”

10.6”