Team Flying Camels Nawar Chaker Pete Dokter Tim Jacobs Adam Swartley Paul Savage Capstone Project February 24, 2005

Team Flying CamelsCapstone Project Driftsonde System Overview The National Center for Atmospheric Research, NCAR, currently has a successful project involving a high altitude pressure balloon that periodically drops sensors (sondes) from a payload NCAR would like to extend flight time, increase maximum number of sondes to fifty while keeping the balloon size the same We are working on a new power system, health monitor system and a release mechanism to meet specific constraints given to us by NCAR to achieve their goals Nawar

Team Flying CamelsCapstone Project Driftsonde System Iridium LEO Satellite Gondola (20-40 sonde capacity) ~16km mb © 2004 Copyright University Corporation for Atmospheric Research

Team Flying CamelsCapstone Project Recap on Constraints Power system -A total weight of no more than 3Kg, including solar panels, control system and batteries -Batteries need to power the system for 24 hours without recharge -Solar panels need to replenish the batteries enough to power system for ten days Release Mechanism -Must be wireless and must be addressable to fifty sondes Cost constraints have become secondary to functionality Nawar

Team Flying CamelsCapstone Project Overall System Diagram Sonde RF Control Sonde RF Control Sonde RF Control Sonde RF Control Sonde RF Control Sonde RF Control Sonde RF Control RF Mod RF Module Gondola RF Control Power System Control 232 to CAN Interface Laptop Solar Panels Solar Panels Two Way RF Link Nawar

Team Flying CamelsCapstone Project System Implementation All hardware will be prototyped Will not be doing board layouts Will be simulating the gondola control system through hyper terminal, which will interface to the CAN bus Two PIC’S will be used: -PIC18F258 -CAN bus capabilities -Five A/D converters -PWM -PIC16F628A -Inexpensive and simple -Will runs on 3.3 V Nawar

Team Flying CamelsCapstone Project System Implementation RF Modules: -Fully contained units with antennas -2.4GHz, 1M bit data rate Solar Panels -Four Iowa thinfilm panels -Rated at 15 V and 100mA Peak Power Tracker -Maximizes power output Batteries -Six Lithium Ion rechargeable -3.7 V, 2000mA-hrs -2x3 configuration for the battery pack Nawar

Team Flying CamelsCapstone Project System Implementation Programming tools -MPLAB IDE 7.0 -MPLAB C18 Compiler -Will program the chip via EPIC programmer, using X-2 development board Nawar

Team Flying CamelsCapstone Project Serial to CAN Bus Link Pete

Team Flying CamelsCapstone Project Gondola RF Control Pete

Team Flying CamelsCapstone Project Sonde Schematic Pete

Team Flying CamelsCapstone Project RF Link Firmware Flowchart: Gondola Pete Clock out Data Check for ACK INIT for RX, (delay) wait for RX INIT for TX, Transmit address and command Wait for TX Command from CAN Yes Good ACK? No DR High? Yes Start

Team Flying CamelsCapstone Project RF Link Firmware Flowchart: Sonde Pete INIT for RX, Wait for RX WAKE UP No Yes Power Down for sleep period Yes Was last Command to drop? Execute command INIT for TX, send ACK Good Address? Clock out Data Check address DR High? No Yes Power Down No

Team Flying CamelsCapstone Project Solar Panels MPT by Iowa thinfilm Operates at 15.4 V and 100 mA Total weight of 26.0g Will wire four in parallel to keep the voltage steady and provide the needed current Tim

Team Flying CamelsCapstone Project Peak Power Tracker I-V characteristic for the solar panels Peak power tracker finds the maximum power point on the curve This is necessary for maximum efficiency Tim

Team Flying CamelsCapstone Project Power System Schematic Tim

Team Flying CamelsCapstone Project Batteries Sanyo Rechargeable 3.6 V and 2 A-Hrs Flat top lithium ion $15.79 a piece Pack will be 10.8 V and 4 A-Hrs consisting of six cells Tim

Team Flying CamelsCapstone Project Batteries Charge Characteristics Tim

Team Flying CamelsCapstone Project Batteries Discharge Characteristic Tim

Team Flying CamelsCapstone Project Power System Firmware Flowchart Adam Stop Charging Duty Cycle=0 Place A/D values in CAN Data Registers NoYes Charge Current<Minimum Initialize I/O ports, A/D, PWM, CAN Previous Watts> New Watts Delta=-Delta PWM Duty Cycle % Max += Delta Continue Charging New Watts = Solar I * Solar V Sample A/D to obtain new values NoYes Delay 50 ms Discharge Voltage < Minimum Sample A/D to obtain new values Yes No Place A/D values in CAN Data Registers

Team Flying CamelsCapstone Project Current State of Project RF System: - Two RF modules and PICs breadboarded - Test code currently functions for two-way communication - Schematics complete - Addressing and command structure next - Prototype ten RF modules after that Adam

Team Flying CamelsCapstone Project Current State of Project Power System: - Schematics complete - Solar panels functional - Test code running for PIC -Developing different aspects of firmware - Prototype and test system components next Adam

Team Flying CamelsCapstone Project Parts List Paul

Team Flying CamelsCapstone Project Gantt Chart Paul

Team Flying CamelsCapstone Project Division of Labor Pete: RF system, hardware implementation, serial link, coding Paul: RF system, CAN bus, serial link, coding, purchasing Nawar: Power system, circuit design, hardware implementation, documentation Tim: Power system, hardware implementation, circuit design, batteries Adam: Power system, firmware, CAN bus, serial link Overall system implementation will be done by the entire team Paul

Team Flying CamelsCapstone Project Questions/ Comments?