MinnRock II design & canister layout

Preliminary Design ReviewNov. 6, 2009

Objective

• The MinnRock II board is a flight characterization board similar to the board that flew last year, the MinnRock (I) project. We aim to look at many aspects of the rocket’s flight, including: spin rate, 3D acceleration, light intensity, pressure, and temperature, and the Earth’s magnetic field as a function of the rocket’s altitude

• Spin rate with a single light sensor• 3D acceleration (x, y, z) as a function of time• The inner pressure and temperature within the canister• The Earth’s magnetic field as a function of the rocket’s altitude• The trajectory of the rocket using a GPS

Other objectives• Capture still pictures while in flight using a camera, and observe the possibility

of switching to video mid-flight.

Expected Results

• We expect to be able to compare data from this years flight to our own existing data

• We wish to answer any questions regarding the use of a GPS or (video)camera

Subsystems

• MinnRock II’s subsystems include:-2 AVR boards-Camera-GPS-All power to be supplied through a single power bus

Camera• Canon Powershot series (specific model for use had not yet

been decided)• Requires 6V of power, which is supplied through its own

battery pack• Writes memory to a 2-4GB memory card• Weight: 6.17 oz• Dimensions:3.52 x 2.53 x 1.69 in.

• The camera is programmable with CHDK memory card programming. This is the technology that has been used for previous flights, and has proved easy to use and reliable

Camera Concerns

• Previous attempts at flying cameras have proved unsuccessful.

• The lens must be directed out the optical port, and it would be favorable for the camera to be as close to the optical port as possible. Therefore, we may have some issues with Wyoming as they have also expressed interest in the window.

• One possible way to discard any chance of camera failure is to power the camera through our power supply rather than batteries. This way, the g-forces cannot force the batteries free.

GPS

• The use of GPS on this flight is pending NASA’s choice on whether or not to fly an antenna on the nosecone

• If use of our own antenna is necessary, the antenna will need to be close to the optical port. This may also pose a problem to our canister integration with Wyoming

AVR Boards• These boards include most of the smaller sensors, and are the

boards that log the information collected by the sensors• We are planning on having two of these boards, since we do

not have enough inputs for the camera with only one board.• There will be some modifications to the AVR board design in

order to split power for the camera and allow connection for the GPS.

• Concerns about the AVR boards:-The way that the boards are configured for the RockOn! Workshop takes up a lot of space, our biggest goal for the boards is to reduce the vertical space taken up by the boards.

Canister layout

• The layout of the canister is still under revisions, but progress is being made.

• The following slides are preliminary solid model drawings of our payload layout.

• The final drawings will be presented at the CDR.

Preliminary Payload Layout

Electrical Schematics

• Our electrical schematics for the MinnRock II project include the schematics used for the RockOn! Workshop.

• We would like to get a copy of these schematics that we can manipulate for our use.

• We plan on changing the plans to fit our design

AVR board

Intra-canister Logistics

• We are currently working with Wyoming to determine location of either team’s experiments.

• Current problems include:-access to the optical port

• Current concerns:-Does the configuration of z-axis CM need to be centered for the canister or only for each experiment?

Functional Block Diagram

Microcontroller

Power Supply G-Switch

CameraGPS

Pressure sensor

Temperature Sensor

MagnetometerAccelerometer

Memory

Power

Data

Memory requirements

- 2 GB SD card with high write speed

400 Hz 300 Hz 200 Hz 100 Hz 50 Hz 10Hz1 input 1.44 MB 1.08 MB 0.72 MB 0.36 MB 0.18 MB 0.036

MB20

inputs28.8 MB 21.6 MB 14.4 MB 7.2 MB 3.6 MB 0.72 MB

• 2 bytes per sensor output data• 19 sensors input• 1 time stamp input• 30 minutes per flight ( 15 minute safety factor)

Memory = 2 (byte/input) * (20) (inputs) * 1800 (sec) * Freq. (samples/sec)

Test Plans

• In order to ensure success we would like to test our payload; our main areas of focus would be:

Mocking up the canister to see if we can receive a signal with an antenna inside the can.

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- Making sure the camera can start up under force. We can test this by pulling on wires, putting force on the camera, etc.

Possible test flights of certain payload components using Professor Flaten’s ballooning equipment.

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One idea for testing is to have the computer continually check the payload’s activation state. If a certain component turns off, we wish to program the computer to turn it back on.

Additional Comments/Concerns

• We will continue to make progress on the canisters layout and logistics.

• We have a lot of work to do but also a lot of reliable personnel working on the project.