ZigBee for Wireless Sensor Networks ZigBee for Wireless Sensor Networks in Space and Field Science in Space and Field Science Mark Foster, CSC / NASA Ames Rick Alena, NASA Ames Intelligent Systems Division Discovery and Systems Health NASA Ames Research Center CENIC: Expanding our Horizons UCI, March 8, 2011
Agenda • Why wireless sensors – Selected application domains • Project Objectives • Solution: TI ZigBee devkit plus SBIR leverage • Recent prototyping and testing • Follow on efforts
Shroud design validation Stiffened panels with overdesigned thickness versus optimized design (Collier Research) • Optimized: less weight (thinner construction) • Instrumentation to validate optimized design during testing and flight • Wired instrumentation scope limits (weight and location) • Wireless: more sample points, alternate datapath to provide distinct data fault assurance
Potential shroud sizes compared to Shuttle
Human and Robotic Exploration Testing • Spacesuit design, monitoring • Human-robot enhancement • Robotic field exploration
Earth Science Technology – Sensor Webs
NASA Facilities - Smart Buildings • Smart energy profile • Building systems management • Smart meters NASA Ames – Sustainability Base
Wireless Sensor Network Project Objectives • Develop “Intelligent” Wireless Sensor Network (WSN) architecture, software and applications to demonstrate fundamental concept of operations • Consider constraints: power, space, weight, cost, time • Evaluate WSN technology function and performance • Reliability • Throughput • Maturity (technology readiness level) • Evaluate WSN suitability for spaceflight certification • Operational environment • Temperature, radiation, pressure, vibration, etc. • RF interference and compatibility • Effect on spacecraft systems • Spacecraft systems effect on WSN Crew vehicle artist concept • Multipath distortion immunity Credit: NASA/Lockheed Martin
Intelligent Wireless Sensor Networks (WSN) Definition • Conform to IEEE 1451 Smart Transducer Interface Standards • Form ad-hoc wireless networks with high- reliability • Provide fault tolerance through mesh routing • Self-manage routing and fault tolerance • Provide Transducer meta-information • Provide unambiguous sensor data with temporal determinism • Provide standard interface to TCP/IP networks • Support open software architecture and applications
Intelligent WSN Standards / Open development • IEEE 802.15.4 provides protocol for ad-hoc Personal Area Network (PAN) formation and management at MAC Layer • IEEE 1451 Standard provides architecture for WSN • 1451.0 Network Capable Application Processor (NCAP) • 1451.4 Transducer Electronic Datasheets (TEDS) • 1451.5 Wireless Transport Protocols (ZigBee) • ZigBee provides framework for network and application support • C language for ZigBee and NCAP firmware and bridge software • Texas Instruments CC2530 System on Chip (SoC) hardware • ARM Co-processor for NCAP • Simple Network Monitoring Protocol (SNMP) for external access
ZigBee Testbed Components • Coordinator - establishes PAN • Routers - forward data • Sensor Nodes - originate sensor data stream • Gateway - connects PAN to IP network (embedded linux)
ZigBee Protocol Stack • Keep approach simple: APS layer and below • Adapt devkit sample code • modify parameters and specific functions • Leverage key functions within supplied object code (Z-stack) • Significant learning curve, but can implement complex systems with modest coding effort.
Wireless Sensor Network Testbed Demonstration Structural Monitoring SDP-1 Prototype WSN Applications on IP Sensor Strain (10 - 1000 µe) networks Strain Sensor End Device Signal Conditioner Strain Gauge 2 - 4 channels 3 axis accel (0-3g) ARCBee A4 Force (0-10 lb) ARCBee 4 thermistors (0-40C) Zigbee ACL-1 A1 FLO-1 Coordinator NCAP 4 thermistors (0-40C) ARCBee A2 Network Capable Application Processor Router Humidity (10-90% RHD) (NCAP) is gateway to IP Module ARCBee networks Temperature (0 - 100 ˚C) A3 Pressure (0-15 PSI) ENV-1
Transducer Electronic Data Sheet Definition for WSN TEDS generation code snippet Bascic TEDS Table void InitStructBasicData(struct BasicData *Basic) { Bit Allowable Range strcpy(Basic->Portal_Number, "192.168.2.12"); Basic->Sensor_Number =1; Length Basic->AD_Channel =0; Basic->TEDS_ID =25; Manufacturer 14 17 - 16381 Basic->Manufacturer_ID = 55; Basic->Model_Number = 0; ID Basic->Version_Letter = 'A'; Basic->Version_Number = 1; Model 15 0-32767 Basic->Serial_Number = 123456; Number strcpy(Basic->User_ASCII_Data,"data"); } Version 5 A-Z (data type void InitStructThermocoupleData(struct ThermocoupleData * thermocouple) Letter Chr5) { strcpy(thermocouple->Portal_Number,"192.168.2.12"); Version 6 0-63 thermocouple->Sensor_Number =1; thermocouple->AD_Channel =0; Number thermocouple->Maximum_Physical_Value_Volts = 3.5; thermocouple->Minimum_Physical_Value_Volts = 0; Serial 24 0-16777215 thermocouple->Maximum_Electrical_Value_Volts = 3.3; thermocouple->Minimum_Electrical_Value_Volts = 0.3; Number thermocouple->Thermocouple_Type ='B'; strcpy(thermocouple->Cold_Junction_Source,"CJC required"); thermocouple->Sensor_Impedance_Ohms = 100; thermocouple->Transducer_Response_Time_Sec = 1.035; strcpy(thermocouple->Calibration_Date,"2007-09-13"); strcpy(thermocouple->Calibration_Initials,"TED"); thermocouple->Calibration_Period_days = 7; thermocouple->Measurement_Location_ID = 89; }
Wireless Sensor Network Development Task Integrate new sensors for specific structural and environmental monitoring – Multi-channel temperature, atmospheric environmental sensors, load cell and accelerometer – New strain gauge sensors, acoustic emission sensors and other sensors relevant to structural health monitoring – Circuits for sensor to SoC connection compatible with battery power 3.0 VDC. – Modify ZigBee firmware and produce new IEEE 1451 Transducer Data Sheets (TEDS) representing new sensor classes and specific prototype sensors – Test new sensors and determine accuracy of measurement
WSN Testbed Hardware/Software Integration Sensor data streams plus TEDS meta-information and WSN status transferred using ZigBee Protocol Sensor Data Display Data Logging Gateway between ZigBee TEDS info Display and Error Detection and TCP/IP networks WSN Status Display ARCBee using SNMP for defining Firmware sensor objects Data Error Sensor Info ARCBee Checking Sensor Module Display Mobitrum NCAP Module Application Data Logs Serial PXA-270 MOBEE-NET 802.15.4 SNMP Queries SNMP Queries SNMPAgent CC2430 Firmware Mn_Driver Ethernet ARCBee TinyOS Computer Firmware Module ARCBee Sensor Module SNMP Queries access sensor data streams plus TEDS meta-information and WSN status information
WSN Prototype Demonstration GUI Mockup Strain Sensor Chart STR-1 TEDS active FLO-1 RSSI STR-2 FLO-1 Battery TEDS: ENV‐1:ENV‐T—Resistance temperature detectors (RTDs) STR-3 Acce Function Select Property/Cmd Description ss Bits Data type (and range) Units ID — TEMPLATE Template ID — 8 Integer (value = 37) — Minimum ConRes (–200 to 1,846, STR-4 Measurement — %MinPhysVal temperature CAL 11 step 1) ºC Maximum ConRes (–200 to 1,846, — %MaxPhysVal temperature CAL 11 step 1) ºC
Reliability and RF Compatibility Test Methods • failover behavior • PAN association time • PAN re-association time • Single hop and double-hop through router • 1, 5, 10 node clusters • 2 sec, 1 sec, 0.5 sec data rates • loss rates under nominal conditions and monitor RF spectrum in ISM band • packet loss rate vs external interference • throughput vs external interference • 802.11 b • 802.11 g • 802.11 n • Bluetooth • multipath environment • reflections from conductive surfaces can prevent data transfer by creating standing wave pattern • metallic enclosures of varying size • packet and throughput loss rates
WSN Reliability and RF Interference Test Protocols • ZigBee and 802.15.4 packet analyzer • association time, orphan detection time and re- association time • Fail sensor node • Fail router node • WLAN sources to create high duty-cycle interference • WiSpy for ISM RF Spectrum • packet loss with SmartRF Studio • Directly runs CC2530 chip • throughput with Transmit App • Send data as quickly as possible
Sensor Failover: Single and Dual Routers • Failover from router to • Failover from router to alternate router coordinator
One-Hop PAN Association and Orphan Transition Times • Scales well • Reasonably fast and consistent • Dependent upon data rate • Reasonably fast and consistent
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