Design and Implementation of Low- Cost Optical Telemetry to Support Radiometric Analysis of the Atmosphere University of Colorado at Boulder Alexandra Hickey, Evan Schomer, Rocky Marcus, and Frank Erdesz 3/14/2013

Mission Overview Mini Cam Subsystem on Polar Cube Low Cost Data confirmation – Through goe tagging – Contextual image comparison Provides simplified means for post launch recalibration 2

Design overview Three Subsystems – Structures – CDH – Power Goal – Compact – Easy to interface – Durable

This Semester Worked toward balloon launch Not met due to technical difficulties that will be talked about later by the different subsystems

Structures

Requirements/Overview fit with in a 1.4in x 1.2in x 1.14in volume Weigh under 200g Easily integrate into Polar Cube Withstand at least 20g’s with a factor of safety of two Maintain all components within operating temperatures 6

The Design PCB structural members Stand offs Nylon washers – Prevent moment about the stand offs Reinforced holes for stand offs

Command and Data Handling (CDH)

Overview/Requirements CDH is handled with an AVR ATmega1284P microcontroller. CDH shall be able to handle image data streaming up 1Mbps from the image sensor as well as interfacing with memory and temperature sensors. CDH shall write any event or peripheral settings data to nv memory. CDH shall be able to locally store all data for an extended period. CDH shall be able to function as a satellite subsystem or standalone system.

Microcontroller and Peripherals Microcontroller ATmega1284P Microcontroller ATmega1284P Camera Module Aptina MT9T111 Camera Module Aptina MT9T111 NV Memory JPEG Data Stream 8-bit parallel Command Interface I2C Memory Interface SPI Temperature Sensors (x3) Temperature Sensors (x3) OneWire Interface

Image Capture Flow Picture Trigger Check memory requirements Prep buffer Find address location of nv memory Create image entry/start headers Set camera settings if necessary Gather timestamp and other data Check memory requirements Prep buffer Find address location of nv memory Create image entry/start headers Set camera settings if necessary Gather timestamp and other data Send Camera Capture Command Load buffer into non-volatile memory Finish EOF headers on nv memory Set low power mode on camera/memory Increment photo ID Add flight log data (time,settings,name) Finish EOF headers on nv memory Set low power mode on camera/memory Increment photo ID Add flight log data (time,settings,name) Return Receive camera data and store into vram buffer Check Camera EOF

Data Storage Images with a maximum size of 1.0 MB per photo at full color resolution will be collected. The camera may cycle through various modes affecting data output size up to 1.0 MB throughout the mission. With a 256MB memory module, up to 254 images and supporting mission log data can be stored locally until uploaded to the main computer memory allowing for a data transfer to be postponed for an extended period. Image SizeJPG100JPG MP 2048x MB504.4KB

Learned Processor bus read optimization for large data transfers. Find sufficient documentation for camera before purchasing. Interfacing with a complex and micro sized camera system and changing various settings through a command interface.

Power

Power Subsystem Requirements Will provide 5V to the microcontroller. Will use 3.3V from PolarCube to power the voltage regulator, DC-DC converter, and memory module. Will provide 2.8V and 1.8V to the camera module.

Functional Block Diagram

Schematics Voltage Regulation

Microcontroller – Camera Interface

Lessons Learned Improvements on PCB design process Learned more circuit debugging strategies

Schedule

Mini Cam BurnDown ListKey Met In Progress Test Over Due The Whip Test25-Feb Drop Test25-Feb The Stair Pitch Test25-Feb Day in the Life/ Cooler Test12-MarCANCELED Day in the life/Cooler Test 22-Apr Day in the Life/Vacuum Test2-Apr Mechanical ItemDate Solid Works Model Finalized14-Feb Parts Order for Prototype ordered15-Feb14-Feb Prototype built25-Feb24-Feb Whip test25-Feb Drop Test25-Feb The Stair Pitch Test25-Feb Design Revisions4-Mar27-Feb Retesting11-Mar Design Finalized12-Mar11-Mar Final Balloon sat Structure constructed8-Apr

Electrical ItemDateDate metStatus 1st board & parts ordered14-Feb board and testing setup assembled22-Feb Testing: electrical, microcontroller, camera27-Feb28-Feb Board v2 designed27-Mar Board v2 ordered & parts ordered27-Mar Board v2 assembled8-Apr Board v2 electrical testing9-Apr CDH ItemDate SD Card/Temperature Working23-Feb Last Day to get camera interface board for reasonable testing time22-Feb13-Feb Camera Working2-Apr Last Software Revision for testing5-Apr Deadline for software revision5-Apr Data anlyzation19-Apr

Conclusion Will provide a contextual image for geo tagging and general data confirmation Allows for easier resolution of anomalous readings Lowers overall Polar Cube mission risk