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Project Proposal Project 7: Drifters. Lance Ellerbe - BS EE Jamal Maduro - BS CpE Peter Rivera - BS ME Anthony Sabido - BS ME. Drifter Design Team. Project Overview. Develop a self-contained network of tracked surface drifters for near coastal application. Housing Electronics
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Project ProposalProject 7: Drifters Lance Ellerbe - BS EE Jamal Maduro - BS CpE Peter Rivera - BS ME Anthony Sabido - BS ME
Project Overview • Develop a self-contained network of tracked surface drifters for near coastal application. • Housing • Electronics • Power System • GPS receiver • Radio transceiver • Microcontroller • Any of these drifters within range of the base station will then be able to send all the information from all other drifters, thus providing a self-contained drifter network. • Many such drifters are deployed globally by the National Oceanic and Atmospheric Administration (NOAA) as part of the world climate observation program.
Legacy Drifter *Picture courtesy of FSU Marine Lab
Operational Description *Picture courtesy of FSU Marine Lab Client will take drifters out to the Ochlocknee Bay and release drifters into the water a set time intervals
Operational Description *Picture courtesy of FSU Marine Lab Then the drifters will be recovered based on pin pointed locations using the GPS and wireless communication from one another.
Electrical Components • Microcontroller • Radio Transceiver • GPS module • Battery • Data Logger
Microcontroller ,Radio Transceiver, and GPS Engineer: Jamal Maduro
Power Systems Engineer: Lance Ellerbe
Power Systems Overview • Low Power Consumption • Each must be able to operate on 3.3V maximum. • The drifter network will be designed to use the least amount of power when transmitting data • The power supply will be selected in order to supply the adequate amount of amp-hours in order to provide enough current for each electrical component to be operational throughout its 15 day deployment.
Power Systems Current Component Selection PROGRESS: • Xbee • Operation Voltage: 3.0 -3.6VDC • Current Draw: • Transmitting current: 256mA • Receiving Current: 50 mA • Transmission Frequency: • every 2.16 min @ 10000 GPS fixes • GPS module • Will be selected for low power consumption and operate at a maximum of 3.3V. (Based on chart on previous slide the current drawn from GPS is approximately 29mA) • Microcontroller • Operation Voltage: 1.8V to 3.6V • Active mode: 230uA • Standby Mode: 0.5uA
Power Systems Testing/ Verification • The testing of this task will include a number of power consumption tests. First, each electrical component will be attached separately to a multimeter or oscilloscope to validate that the component is operating within its electrical specifications. • Second, based on the results in the previous step the results can be then used to tweak network parameters such as transmission time or microprocessor algorithms in an attempt to lower power consumption and increase theoretical operation time.
Power Systems Time of Operation • 15 days of operation = 360 hours of operation • Required GPS fixes: 10,000 • Number of Fixes in 15 days: GPS fix every 2.16 min or 129.9 sec • FCC rule: The average time of occupancy at any frequency must not be larger than 0.4 seconds when using the frequency hopping spread spectrum. • Maximum current drawn per transmission/reception of all electrical components: Approximately 336mA
Power Systems Worst Case Scenario: 0.4 sec for each transmission/reception • 336 mA for 1.11 hours of ACTIVE operation • sleep mode considered negligible (uA range). • 336 mA × 1.11 hours = 372.96 mAh • Battery needed would be something with 3.3 V and greater than 372.96 mAh
Power Systems Criteria for Making Battery Selection: • Run Time • Volts (Power) • Amp-Hour Rating • Rechargeable • Life Cycle • Temperature of Operation
Power Systems Power supply considerations: • (1)Lithium Ion • Lithium Manganese Nickel • Lithium Polymer • Nickel Cadmium (NiCad) • Nickel Metal Hydride (NiMH) • Photovoltaics
Power Systems Lithium Ion Battery: • These batteries are able to handle excessive current applications. • Lithium batteries are great for long-term use. • Lithium batteries also perform well in extreme temperatures. • Increased life cycles over Nickel cadmium (NiCad) and Nickel Metal Hydride (NiMH) batteries. • Lithium ion batteries are also cheaper to manufacture than lithium polymer batteries, so when cost is a factor, lithium ion is the choice. • Much lower self-discharge rate than Nickel Metal Hydride (NiMH) batteries. • Wide variety of shapes and sizes efficiently fitting the devices they power.
Power Systems Ideal Battery Configuration Parallel configuration would be ideal to increase the amount of Amp-Hours to supply the adequate amount of current to Microcontroller, GPS module and Radio Transceiver for a 15 day period. EXAMPLE
Power Systems Voltage regulation If battery chosen has a nominal voltage of more than 3.3 V, a voltage regulator will need to be implemented to maximize battery life and supply the correct operating voltage to the components.
Power Systems PCB protection • Lithium Ion batteries must connect to a protection circuit module to protect Li-Ion Battery from overcharge, over discharge and to prevent accidental battery explosion due to its extra high energy density.
Power Systems Once all component selection has been finalized, the battery will be chosen based the voltage needed and the highest mAh that can be found.
Hull Design Engineers: Anthony Sabido and Peter Rivera
Hull Design • Increase water drag while decreasing wind drag • Watertight • Resist corrosion in saltwater • Survive light to medium impacts on potentially sharp objects • Easily duplicated
Legacy Casing *Picture courtesy of FSU Marine Lab
Hull Design • Semi-spherical shape. • The electric components will be stored in the center • Top will be as flat as possible.
Hull Design • Low weight • High stability • Easy to Seal • Easily Fabricated • Low Cost
Hull Components • Base • Lack of edges reduces snagging. • 3 Piece design reduces materials and simplifies fabrication. • Allows for foam filling. • Top • Flat panel top decrease vertical profile. • Simple sealing process. • Quick component access.
Exploded View • Six screws fasten the top to the base. • Sealing achieved by 1 main rubber seal and 6 rubber coated washers.
Issues Encountered • Fastening • Need aluminum ring to secure the top. Veck Female Bonding Fastener
Issues Encountered • Fastening • Excessive torque • Solutions • Bonding Fasteners • Torque Key Ritchey Carbon Torque Key - Cycle Club Sports
Specifications • Waterproof to 5m (CAP-04 & REQF-06). • Low profile to reduce wind drag (CAP-06). • Painted to camouflage with the water (CAP-07). • Maximum weight of 0.5 kg (REQF-04). • Overall height less than 10 cm (REQF-05).
Hull Testing • Water tightness • Floatation
Hull Testing • Vibration testing will be done on a vibration table, where the drifter will be shaken at a variety of frequencies for endurance.