Lance Ellerbe - BS EE
Jamal Maduro - BS CpE
Peter Rivera - BS ME
Anthony Sabido - BS ME
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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.
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Electrical Components
 Microcontroller:
 TI (Texas Instruments) MSP430G2553 microcontroller
 Radio Transceiver
 XBee-Pro XSC RF module’s
 GPS module:
 Maestro A2100
 Battery
 Lithium ion
 Temperature Sensor
 Maxim DS18B20
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Engineer: Jamal Maduro
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QUICK REVIEW
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Microcontroller
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XBee Modes of Operation
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XBee Data Verification Chain
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GPS Diagram
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Temperature Sensor
Overview
 Compared to the thermistor, the DS18B20 has
memory and thus the temperature can be
held until a more convenient time when the
data can be logged.
 Digital temperature sensor that uses serial
communication through the DQ pin.
 1 temperature reading per GPS fix
 Converts Temperature to 12-Bit Digital Word
in 750ms (Max)
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UPDATED SYSTEM
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General Layout
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System Flow Chart
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Completed Tests
1. UART Test (Completed)
A loop back circuit was made by connecting the
microcontroller’s transmission pin to the receiving pin and
then the following test programs located in the appendix
were ran:
• “UART_loop_9600baud.asm” – a continuous stream of
data at a constant baud rate
• “UART_echo_9600baud.asm” – real-time data input
response at a constant baud rate
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Completed Tests
2. SPI Test (Completed)
A loop back circuit was made by connecting the
microcontroller’s SOMI to the SIMO pin of another identical
microcontroller (or loop back within one microcontroller),
connecting and synchronizing, and their corresponding
clock pins to one another. The output was viewed on a
terminal emulator.
• “SPI_UART.asm” – data passed in through UART
transferred to SPI and outputted out of UART
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Completed Tests
3. Timer Test – System wakeup simulation (Completed)
The watchdog timer is configured to alternate two LEDs
every 10 seconds and output a character via UART and SPI.
Various time intervals were tested including the actual time
that the tracking system will be asleep and active.
• “Low_Power_Timer_Comm.asm” – data passed in
through UART transferred to SPI and outputted out of UART
transitioning out of low power mode.
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Completed Tests
4. Sleep Mode Test (Completed)
The microcontroller was connected to a digital multi-meter
and the voltage level of all of its operation modes were
recorded to ensure that the desired reduction in power
consumption was achieved.
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Completed Tests
5. XBee UART Communication (Completed)
A circuit was made by connecting the microcontroller’s
transmission pin to the receiving (Din) pin of the XBee and
the output (Dout) from the XBee was connected to a RS-232
level shifter via a DB9 connection to a laptop computer and
was observed on a terminal while running the test program
located in the appendix:
• “UART_cmd_57600baud.asm” – send binary commands
to the XBee radio module
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Completed Tests
6. XBee Firmware Test (Complete)
Connect the XBee module to the RS-232 level shifter via a
DB9 connection to a laptop computer and verify that the
default settings are correctly initialized such that the default
interface is binary command mode as opposed to AT
command mode. Configure the desired settings if the
default is incorrect and retest to ensure that firmware has
been correctly updated and will not be reset upon loss of
power.
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Pending Tests
1. GPS SPI Communication (Pending...)
A circuit will be made by connecting the microcontrollers
SOMI pin to the SIMO pin of the GPS module, connecting
and synchronizing their corresponding clock pins, and
observing the data collected by the microcontroller in its
RAM and/or registers.
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Pending Tests
2. Temperature Sensor GPIO Communication (Pending...)
A circuit will be made by connecting a GPIO on the
microcontroller to the DQ pin of the digital temperature,
different heat sources will be applied to the sensor and the
output will be compared against a thermometer to ensure
that the sensor is functioning correctly. The GPIO will be
switched from input and output as needed.
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Pending Tests
3. GPS Firmware Test (Pending...)
Connect the GPS module to the RS-232 level shifter via a
DB9 connection to a laptop computer and verify that the
default settings are correctly initialized such that the only
output is the NMEA RMC string. Configure the desired
settings if the default is incorrect and retest to ensure that
firmware has been correctly updated and will not be reset
upon loss of power.
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Pending Tests
4. Data Logging File System Test (Pending...)
Connect the data logger (with the desired memory card
inside) to the RS-232 level shifter via a DB9 connection to a
laptop computer and verify that the file system is correctly
configured. Test all immediately relevant operations such as
reading, writing, and erasing data.
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Pending Tests
5. Temperature Sensor Serial Comm Test (Pending...)
The temperature sensor will be tested in conjunction with
the microcontroller. The timing limits of communication will
be tested using the timer in the microcontroller to ensure
that the suggested timing protocol in the datasheet will
support correct functionality.
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Engineer: Lance Ellerbe
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Radio Transceiver Antenna
 The antenna has a operational frequency between
868MHz-928MHz.
 This frequency range will allow the for the drifter to
operate by relaying its position to nearby drifters via
radio transmission on the 915MHz ISM (Industry,
Scientific, Medical) band.
 The antenna has a gain of 3.1 dB, doubling the signal
strength (an output-to-input power ratio of 2:1)
which translates into a gain of 3 dB which is the half
power point.
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Radio Transceiver Antenna
Interfacing Radio Transceiver antenna
 The radio transceiver antenna will be the
implemented into the drifter system through the
Xbee transceiver using a U.FL connector adaptor.
This connector cable interfaces U.FL RF connectors
to RP-SMA antennas.
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GPS Antenna
 SL1204 GeoHelix.
 Active Antenna
 Gain of +18 dB
 Beam width of 135o .
 Operational voltage: 1.8-3.6V
 Draws 3.4 mA max
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GPS Antenna
Interfacing GPS antenna
 The Maestro A2100 also supports active antennas
directly, by offering an antenna voltage feed pin (VANT –
pin 15)
 GPS module provides a maximum current draw of 50mA.
 This active antenna should have a gain ≥ 15dB but the
total gain should not exceed 30dB.
 50 Ω PCB strip line is required
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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.
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Power Systems
Current Component Selection :
 Xbee
 Operation Voltage: 3.0 -3.6VDC
 Current Draw:


Transmitting current: 256mA
Receiving Current: 50 mA
 Maestro A2100-A/B
 Operation Voltage: 3.0V - 3.3VDC
 Current Draw:


Peak Acquisition Current 45mA
Antenna current: 3.4 mA
 Microcontroller
 Operation Voltage: 1.8V - 3.6V
 Active mode: 230uA
 Standby Mode: 0.5uA
 Temperature Sensor
 Current Draw: 1.5mA
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Power Systems
Voltage Regulator
MAX882/MAX883/MAX884 line regulator
 The regulator input supply voltage can range from 2.7V to
11.5V
 Low Dropout Voltage: 220mV
 Fixed Output voltages: 3.3V and 5V
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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.
Battery
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Power Systems
Current Component Selection PROGRESS:
 Worst Case Scenario: 1 sec for each transmission/reception
 401.23 mA for 2.77 hours of ACTIVE operation
 sleep mode considered negligible (uA range).
 401.23 mA × 2.77 hours = 1111.407 mAh
 Battery needed would be something with 3.3 V and a capacity
greater than 1111.407 mAh to adequately provide enough
current to stay operational for a 15 day deployment.
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Power Systems
Battery
 Ultrafire 18650 Protected Rechargeable
Lithium Ion Battery
 Nominal Voltage: 3.7V
 Capacity: 3000mAh
 The PCB protection that is needed for
Lithium Ion batteries already integrated in
the battery.
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Power Systems
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, Radio Transceiver and Temperature Sensor for a 15 day
period.
Using 3000 mAh
Batteries
Voltage = 3.7 V
V2
3.7 VDC
V3
3.7 VDC
Capacity =
6000mAh
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Power Systems
 Power Systems Diagram
V1
3.7Vdc
LBI
LBO
OFF(STBY)
SET
-
GND
PCB
Protector
Max882/884
IN
GND
OUT
+
V2
3.7Vdc
Delivers 3.3V to the
power supply pin of
each component in
the system
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Power Systems
Component Testing
 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.
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Power Systems
Voltage Regulator Test
The testing of this component in the power systems will test the different
operation of the MAX884 linear regulator.
 Using a multimeter we will input different values of input voltages(2.7V to
11.5V) and measure the current and voltage on the output pin. The results
from this test will show how the effects of different voltages and currents
on the input pin will change the output current on the output pin on the
voltage regulator.
 Test the different capabilities of the voltage regulator such as Shutdown
Mode or Standby Mode. Based on this test we will see which Mode will be best
to achieve the least amount of power consumption, but also allows the
regulator to activate when needed.
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Power Systems
Battery test
The testing of the battery includes testing the battery under a
load similar to the drifter system to see how long the battery
can last.
 In this test we will connect the battery to a simulated load that
draws approximately 400mA of current and test the battery
over a certain amount of time. We would record the batteries
beginning voltage and current, then record the voltage and
current after the battery has been drained for a certain
amount of time. This test would ensure that our drifter system
will adequately be powered throughout a 15 day deployment.
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Engineers: Anthony Sabido and Peter Rivera
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Overview
1
2
1. Top
2. Bowl
3. Screw-in
Deck Plate
3
Major Features:
•Symmetric
•Semi-Circular Profile
•Fiberglass Hull
•Off-the-Shelf Deck
Plate
•Low Cost
•Easy Fabrication
Fiberglass
 Low Density:
 Cloth: 2.6 g/cm3
 Resin: 1.3 g/cm3
 Low Cost
 205-B Slow hardener (0.86qt.): $37.20
 105-B Epoxy Resin (1 gal): $78.29
Sealing the Hull
 6” diameter deck



plate
Screw-in design
Made of Durable
ABS plastic
O-ring for water
tight seal
Low cost - $7.89
Updated Hull
Mass Calculations
Component Mass
(Legacy)
Component Mass
(New/Proposed)
Antenna
9.1
g
Antenna
26.87
g
GPS Antenna
9.1
g
GPS Antenna
8.01
g
GPS Module
4.5
g
GPS Module
1.33
g
Radio Transceiver
4.5
g
Radio Transceiver
3.87
g
Batteries (2)
45.4
g
Batteries (2)
45.4
g
Board w/Processor
40.0
g
Microprocessor
1.22
g
Hull
2400
g
Deck Plate
309.7
g
2513.1
g
Hull
1962.7
g
5.51
g
SD Card
~5
g
Temp Sensor
<1
g
Printed Circuit Board
~40
g
2410.3
g
Total
SD Breakout Board
Total
Initial
Dimensions
- Drifter
Updated
Dimensions
- Drifter
Updated
Dimensions
- Drifter
Major Changes
- Dimensions
 Radius of the hull’s contour decreased from 15” to
10.875”
 Major diameter decreased from 47.24cm to 38.68cm
 Overall hull height decreased from 9.40cm to 7.55cm
# - Latest Dimensions
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Design Validation
- Component Fitment
 Each major
component has
been solid
modeled to
ensure fitment
into the hull
 Masses added to
double-check the
center of mass
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Final Updates
 2 Piece Hull Design changed to 3 piece assembly
 Deck plate purchased is smaller and lighter
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Exploded View
58
Final Updates
 2 Piece Hull Design changed to 3 piece assembly
 Deck plate purchased is smaller and lighter
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Rough PCB
Footprint
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Final Updates
 2 Piece Hull Design changed to 3 piece assembly
 Deck plate purchased is smaller and lighter
 Temperature sensor placement finalized
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Temperature Sensor
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Performance Analysis
Testing in Detail
 Preliminary Floatation
 Check water level. Our goal is to have the drifter sit low
enough in the water to avoid wind drag but not too low that it
loses stability.
 By adjusting the diameter and bowl depth, we can change the
volume and draft level.
 We can perform this test in any body of water
Tests
 Preliminary Water tightness / Floatation Tests
 Preliminary Stability Tests
 On-Site Stability Tests
 Final Water tightness tests
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Testing in Detail
 Preliminary Water tightness
 Even a slight water leak in an electrical system can be
catastrophic
 While testing floatation, we will also examine the
drifter’s hull for leaks. After floating the drifter for
several minutes, we can examine the inside to check if
water entered the compartment.
 At Sea Tests
 After the initial tests to confirm stability, floatation, and
water tightness, we will take the hulls to the test area
(Ochlocknee Bay) to examine their behavior with a payload of
equivalent weight of the electrical components.
Testing in Detail
 Final Water tightness
 Our final test will involve placing an empty drifter hull at the
bottom of a pool of water approximately 5m deep.
 There is a chance that the drifter could, under some
circumstances, be completely submerged at depths of around
one meter.
 This test would allow for a safety factor.
Testing of All Hulls
 Though the on-site test at Ochlocknee Bay will be
performed on only a select few designs, each hull
constructed will undergo the series of tests listed
before.
 Assuming that because one individual hull completed
the tests does not guarantee that some small
imperfections in a later copy will allow all the drifters
to perform on par.
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Base Station
 The base station will be a mostly stationary system.
 The initial use by the sponsor will involve holding the
base station in hand or on a boat.
 Later use will involve leaving the base station
unattended.
 To save money, the base station will not require a GPS
receiver (or antenna) and will not require a regular
drifter hull.
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Base Station
 The container of the base will be placed in an otterbox.
 Otterboxes are waterproof boxes (up to 100ft) that also float.
 This design will allow the sponsor to leave the base station
out in the elements for extended periods.
 Or place the station on the roof of a building and connect a
high-gain tower antenna for
better reception.
 This box is an Otterbox 3000.
It’s dimensions would allow
the use of the same PCB placed
in the regular drifters.
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Project Overview - Timeline
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1/8 1/14
1/15 1/21
1/22 1/28
1/29 2/4
2/5 2/11
2/12 2/18
2/19 2/25
2/26 3/3
3/4 3/10
3/11 3/17
3/18 3/24
3/25 3/31
4/1 4/7
4/8 4/14
4/15 4/21
Week Dates
1
1/1 1/7
Week #
Finish Code
Test Xbee Range
Milestone 1
- M1 Report
- M1 Presentation
Finalize Hull Design
- Construct Prelim. Hullls
- Test Stability
- Test Watertightness
- Secondary Hull Testing
Test GPS
- Mount GPS Chip
Order PCB
- Design PCB
Test Networking Capabilities
Purchase Batteries
- Determine Quantity
Fabricate Base Station
- Select Otter Box
Test Power Systems
Develop Instruction Manual
Milestone 2
Milestone 3
- M3 Report
- M3 Presentation
72
Project Percentage Complete
40.5%
59.5%
Remaining
Complete
73
Budget
Expenses
Microcontroller
USB to RS232 Adapter
RS232 Shifter
Development Board
Deck Plate
Filler Compound
Fiberglass Resin
Fiberglass Hardener
Mem. Card Breakout Board
GPS Antenna
Temperature Sensor
Antenna Adapter
Radio Transciever
GPS Module
Radio Antennas
Fiberglass
Batteries
Voltage Regulator
Printed Circuit Board
PCB Protection Module
Column Totals:
Quantity Unit Price
6 $
2.80
5 $
11.95
5 $
13.95
1 $
4.35
4 $
7.89
1 pint
$
15.50
1 gallon $
78.29
0.86 qt
$
37.20
5 $
9.95
5 $
22.95
5 $
4.25
5 $
4.95
5 $
39.00
5 $
19.44
5 $
7.95
15 sq ft $ 4.74 / sq ft
10 $
10.50
5 $
3.50
5 $
13.75
5 $
3.90
Total
$ 16.80
$ 59.75
$ 69.75
$
4.35
$ 31.56
$15.50
$ 78.29
$ 37.20
$ 49.75
$ 114.75
$ 21.25
$ 24.75
$ 195.00
$ 97.20
$ 39.75
$ 71.10
$ 105.00
$ 17.50
$ 110.00
$ 19.50
Shipping
$ 8.90
$ 18.78
$ 13.84
$ 9.34
xxxx
xxxx
xxxx
xxxx
$ 12.77
xxxx
xxxx
xxxx
$ 15.00
xxxx
$ 12.00
xxxx
$ 10.00
$ 9.00
$ 18.00
$ 7.00
Total
w/Shipping
$ 1,178.75 $ 134.63 $ 1,313.38
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Technical Report:
“Surface Circulation Study of Waters Near Ochlockonee Bay, Florida”
- Peter Lazarevich and Dr. Kevin Speer
Project Description :
“Tracking the coastal waters: a wireless network of shallow water drifters”
- FAMU-FSU College of Engineering
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