Team µBuoyBruce Chen Phong NguyenSpencer Krist

Eric Stevens Louis Tuey

Floatable Sonde, deployed via UAV

Measures water temperatures at 3 depths below ocean surface

Help scientists better understand arctic sea ice melt

Project Recap

Eric Stevens

Inputs◦ UAV Commands◦ Input (Temperature/ GPS) Data

Outputs◦ Packaged Temperature and Position Data

Level 0 Functional Decomp.

Micro Buoy

UAV Commands

Data In

Data Out0.0

Block diagram O- Level 0 Block DiagramEric Stevens

PCB Electronics◦ Inputs: UAV Handshaking Commands, Raw Temp Data◦ Outputs: Packaged Temp. and Location Data

Power Supply◦ Output: Regulated voltages to PCB board and Thermistors

Thermistor String◦ Inputs: Power for current supply, microcontroller request for data◦ Output: Raw temperature Data to ADC

Level 1 Functional Decomp.

Block diagram 1- Level 1 Block DiagramEric Stevens

PCB Electronics

(µCU, RF, GPS, Memory, PWR, Thermistor Support)

Power Supply

(Battery, 3.7V)

Thermistor String

UAV Commands

GPS Data In

Data Out

1.0

Level 2 – Functional Decomposition

Inputs

 UAV Commands- Radio ReceiverInput Data – Satellite data Thermistor String- Temperature data

Outputs

 Data Out- Radio Transceiver (GPS + Temp.)GPS commands- Activates modes, requests information from the GPS 

http://blog.timesunion.com/opinion/clean-up-space-with-tungsten-sandblaster/12060/broadcasting-satellite/Eric Stevens

EzRadioPRO◦ Si4430 ISM Transceiver

Frequency Range: 240-960 MHz Output power range: +20 dBm Data Rate: 256 kbps Low battery detector Temperature range: -40 to +85 ℃ Sensitivity: -121 dBm

Radio

http://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/Si4330.pdf&src=DocumentationWebPart

Phong Nguyen

Inputs

DC supply voltage 1.8-3.6VSerial Clock from Microcontroller (SCLK)Data Transfer (MOSI, MISO)Transmit/Receive (Register 07h, bits txon/rxon)Operating Mode (Transmit, Idle, Receive)Output Power (Register 6Dh, txpow[2:0])

OutputsData Interrupt

Block Diagram

Phong Nguyen

Operating Modes

Transmit wIdle ReceiveTransmit

Phong Nguyen

Communication protocols

Phong Nguyen

Microcontroller SI-1000

Bruce Chen

Power ModesPower Mode

Description Wake-up Sources

Power Savings

Normal Device fully functional N/A Vdd= 1.8-3.6V I = 5mA

Idle Very easy to wake up Any Interrupt GoodNo Code ExecutionVdd= 1.8-3.6V I = 3mA

Stop A reset is required to wake up.

Any Reset Good No Code Execution

Suspend Similar to Stop Mode, but very fast wake-up time.

SmaRTClock,Port Match,Comparator0,RTS pin

Very GoodNo Code ExecutionVdd= 1.8-3.6V I = 0.77μA

Sleep Ultra Low Power and flexible wake-up sources.

SmaRTClock,Port Match,Comparator0,RTS pin

ExcellentPower Supply Gated.All Oscillators except SmaRTClock DisabledVdd= 1.8V I = 0.61μA

Bruce Chen

Module: Start

Turn on Turn on GPS, Radio

Check if GPS and Radio are

on

Calibrate Timestamp Time

Return Error

Enable all Interrupt:

smaRTClock,Port Match

Setup the SmarRTClock:

TimeLow Priority

Setup the Port Match:

P0High Priority

C=0;Sleep(GPS);

Sleep(Radio);Sleep(MC);

No

Yes

Turn on all the component

Bruce Chen

Module: Start

Set up the Interrupt◦ Address 0xA8, 0xE6, 0xE7◦ Priority -> 0xF6, 0xF7

Sleep◦ Microcontroller 1 into Address,0xF6 bit 7◦ GPS low into pin#4◦ Radio “07h” into register

0h

Bruce Chen

Measure temperature N times per hour Get the position every hour Store the data with Timestamps

Wake(MC)

If an hour

pass(C>60/N)

C++;Sleep(MC)

No

YesWake(GP

S)

Store GPS data and

timestamps

Calibrate MC the Time;C=0;

Sleep(GPS)

Bruce Chen

SmarRTClock Handler --Low Priority

Store the Temperature

and timestamps

Store the Temperature

and timestamps

Wait(35)

Port Match Handler --High Priority Send the signal to UAV with ID and position Send the signal to UAV with the stored data

Wake(MC)Wake(Radio)

If(ID==Reuested_

ID)

No

Yes

Wake(GPS)

Send ID and

Location

Send data base on

command

Bruce Chen

Sleep(Radio)Sleep(MC)

Sleep(GPS)

Command Decoding

Thermistor Bridges

-Design CriteriaTemperature Range: -10°C25°CAccurate to at least 0.1°C

Using 3.3V from a GPIO PinUsing a 10 KΩ resistor and a 10kΩ (@25°C) thermistor

Murata PN: NCP18XV103J03RB Or Vishay PN: NTCLE100E3103JB0

Louis Tuey

With given componentsΔV = 1.142 Volts over temp rangeTemperature Resolution:

For 10 Bit ADC

For 12 Bit ADC

BitCV

VT oDD /0987.0210

BitCV

VT oDD /02469.0212

Louis Tuey

Power Budget With the smallest mass possible, power the buoy

for a period of greater than 2 weeks

Mode Freq Period Discharge Rate

Ah req

Transmit 1/Day 2 min 85 mA 39.7 mAh

GPS 1/hr 1 min 40 mA 224 mAh

Temp Sampling

1/hr 1 min 2 mA 11.2 mAh

Cont operation

Cont 14 Days 1 µA 0.336 mAh

Total Power Budget 275 mAh

Assuming 80% Power management 343 mAh

Louis Tuey

DC Voltage Rails Microcontroller RF module 3.3 Volts up to

100mA

GPS 2.7 and 3.3 volts up to 50 mA

Louis Tuey

Texas Inst: TPS62240 Regulator

Louis Tuey

Model:◦ Fastrax IT03-S

Primary Objective: ◦ Provide time and position

Interface: ◦ CMOS- 2 port UART interface◦ GPS Handler

Fix Times:◦ Cold Start: 35 seconds ◦ Warm Start:34 s◦ Hot Start: 4 s

GPS

http://www.fastraxgps.com/products/gpsmodules/03series/it03s%28eol%29/

Spencer Krist

GPS Data Handling

Positioning Data ◦ $GPGGA, 084053.39,6016.3052,N,02458.3735,E,0,00,0.0,46.6,M,,*5D

Type – global positioning system fix data Time – 08 Hours, 40 minutes, 53 Seconds and 39 hundredths of a

second Latitude- 60 degrees and 16.3052 minutes North Longitude- 24 degrees and 58.3735 minutes East Fix Indicator – 0=Fix not valid, 1=Fix valid Number of Satellites- 0 Horizontal Dilution- 0.0 Altitude- 46.6 meters

Time Data◦ Similar string to positioning string

Allows for update of GPS modules real time clock, functions in sleep mode

Spencer Krist

GPS Exchange Microcontroller requests GPS position and

time data hourly GPS receives data from satellites

◦ 35 s max fix time (TTFF) Microcontroller receives data strings from

GPS module Microcontroller parses and saves time and

position data Data is logged in flash memory

Spencer Krist

Division of Labor: Revisited

Component Primary Secondary

EE

Radio Phong Eric

Power Management LouisSpencer

Bruce

Thermistors Louis Spencer

GPS Spencer Phong

PCB Layout Louis Bruce

ECE

Microcontroller Eric Bruce

Memory Bruce Eric

Software Bruce Eric

Project Management

Budget Spencer PhongSpencer Krist

Equipment-Major Components Have:

◦ SI 1000 development kits◦ Fastrax IT03-S◦ Batteries – Polymer Lithium Ion- 850 mAh

On Order: ◦ Additional Fastrax IT03-S

Need: ◦ PCB ◦ Memory ◦ SI 1000 (Actual Chips)

Spencer Krist

Source of Funding

Blank Check

Source Name Value

NASA grant through professor Scott Palo of the Aerospace Engineering Department

As needed $0-$500

UROP Grant $1000

Personal Funds $500

Total $1300-$2000

Spencer Krist

Budget: Revisited

Item Name Cost (Estimates)

Microprocessor (SI 1000) $45 (3 Units at $15 each)

SI 1000 development board Free ($150 each, we have 4)

PCB $150

Memory (SD Card) $15

Radio Included with Microprocessor

GPS (Fastrax IT300) $50

Batteries $75

Misc. parts $200

Expo $200

UROP ($1000)

Total ($265)

Spencer Krist

Schedule

Spencer Krist

Milestone 1◦ 2 Dev Boards communicating◦ Thermistor circuit taking temp data

Milestone 2◦ Thermistor string feeding temperature data to

microcontroller through ADC◦ Data storage in flash memory◦ GPS data

Milestone Goals

Spencer Krist

Floating buoy in water tank

◦ Dev Board connected to PC acting as UAV

◦ Buoy responds to Dev Board commands with temperature and position data

◦ Data displayed on PC monitor

Expo Day Goals

Spencer Krist

PC

Questions?