Wireless Sea Measurement

UnitA Plan for Aarne Halme Project

Juha VanhalakkaErkka Mutanen

ContentsO Project SpecificationO XBee Radio ModuleO Other ComponentsO Concept ArtO SWOT AnalysisO Seabed MountingO Arduino EnvironO CodeO CostsO Project Schedule

Project SpecificationO Implement a prototype of a wireless sea

measuring station for professor Aarne Halme’s summer cottage

O Use wireless connectivity to integrate to existing home automation system (ThereGate Linux server)

O Keep things small and energy-independent but also as cheap as possible

O Prototype finished in December 2013

Block Diagram

XBee-PRO Radio Module

O Operates at 2.4 GHz ISM band (ZigBee)

O 100 / 1500 m indoor/outdoor op. radius,

O TX current 100-215 mA, RX current 50 mA

O Link data rate 250 kbps (IEEE 802.15.4)

O 5 x 10bit AD converters

Measurement CircuitsO Voltage splitting

circuit for pressure sensor and power monitoring

O Case temperaturemeasurement

Measurement Circuits II

O PT100 (R10) measurement done with 2 differential amplifier

Power Management

O Battery keeps the Sea Unit running during night time

O High efficient chopper converters used

Other ComponentsEmbedded Antenna (OPTIONAL)O 2.4GHz puck antennaO Fully water-proof

Multicomp Solar PanelO 800 mW polycrystal panelO Weather-proof with aluminum

framesO Voltage output > radio circuit

voltage

CONCEPT ART

Project AnalysisStrengths• Easy to implement• Low-cost installation and

maintenance• Automated data history graphs

Weaknesses• Robustness to weather?• Powered by sun, need sunlight• Removal out of water during

winter

Opportunities• No players in consumer market• New ZigBee technology• Extendable for wave size

tracking

Threats• Winter conditions• Corrosion

Prototype

Seabed MountingO Many possibilities:

1. Mounting near pier on dedicated pole2. Mounting on pier (measurement under quay)3. Mounting near pier on non-dedicated pole

O Aluminum tube (pole)

O Commercial metal shoes with spikes for underwater attaching

O Not available on rock bottom

O Prefer wood constructs over metal (Finnish style)

Arduino EnvironO Open-source physical computing

platformO Microcontroller board +

development environO Based on ATMEL’s ATMega

processorsO Objective-C “Processing” language

CodeO Device pairing and routingO Radio RX/TX loop codeO Sleep cycle codeO Request for resend code

O Measurement filtering (OPTIONAL)O Measurement pre-processing

(OPTIONAL)

CostsO ZigBee XBee RF chip 40€O Solar panels 8€ x2O Hydrostatic pressure sensor

WIKA LH-100€ (540€)O Resistors, switches, LEDs,

optic fiber 5€O Battery pack 5€O Sea bed mount 60€O Casing 40€

TOTAL costs 166€

Project ScheduleO Project Plan 25.09.O Progress Report 30.10.

+ electronics ready, code runningO Demo A 20.11.

+ casing ready, code readyO Demo B 27.11.

+ mounting prototype doneO Documentation done 10.12.

End