Mica, Mica2, MicaZ Katarzyna Bilinska Marcin Filo Rafal Krystowski Supervisor: Dr. Waltenegus Dargie

Agenda Motivation Architecture MICA, MICA2, MICA z Sensing sub-system Operating system Communication phases Test of Mica Mica2

Motivation Elimination of human involvement in gathering information Smart environment relies first and foremost on sensory data from the real world.

What is Mica? Mica, responsible for -processing, -storage -power supply - sending data to base station Sensing board, responsible for -sensing Ref. 1

Why mica? Mica wireless platform serves as a foundation for the emerging possibilities. Nearly a hundred research groups currently use Mica nodes Mica is created with off-the-shelf hardware Mica does not require use of predefined protocols (except Mica Z) Ref. 3

System architecture

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

Processing sub-system Functions Application execution Resource management Peripherial interaction

Processing Sub-System: Mica Atmel AVR Atmega 103L (MCU) 121 Instructions - Most Single Clock Cycle Execution Up to 6 MIPS Throughput at 6MHz 128k Bytes of In-System Programmable Flash 4K Bytes Internal SRAM 4K Bytes of In-System Programmable EEPROM 53 Programmable I/O Lines 3 hardware timers, 1 external UART, 1 SPI port Atmel AVR AT90S2313 coprocessor 8-pin flash-based microcontroler with an internal system clock 5 programmable I/O Lines Maxim DS2401 (silicon serial number) Low cost ROM device Unique, factory-lasered and tested 64-bit registration number guaranteed no two parts alike No power requirements (no need for an external power source) Minimal electronic interface (typically a single port pin of a microcontroller) In Mica works at 4 MHz Limited program space Used to load the programme into main processor Used to identify Mica

Processing Sub-System: Mica2, MicaZ Atmel AVR Atmega 128L (MCU) 133 Instructions - Most Single Clock Cycle Execution Up to 16 MIPS Throughput at 16MHz 128k Bytes of In-System Programmable Flash 4K Bytes Internal SRAM 4K Bytes of In-System Programmable EEPROM 53 Programmable I/O Lines 3 hardware timers, 2 external UART, 1 SPI port self reprogramable hardware multiplier JTAG debugging support (real-time, in-system debugging) Maxim DS2401 (silicon serial number) Low cost ROM device Unique, factory-lasered and tested 64-bit registration number guaranteed no two parts alike No power requirements (no need for an external power source) Minimal electronic interface (typically a single port pin of a microcontroller) In Mica2,MicaZ works at 7,4 MHz No need of coprocessor No need in MicaZ

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

I/O Sub-System Functions Interface with sensing boards Interface with programming boards Program and communicate with other devices

I/O Sub-System The I/O subsystem interface consists of a 51-pin expansion connector eight analog lines, eight power control lines, three pulse-width-modulated lines, two analog compare lines, four external interrupt lines, an I2C-bus from Philips Semiconductor, an SPI bus, a serial port, a collection of lines dedicated to programming the microcontrollers. expansion connector Ref. 3

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

Secondary storage Sub-System Functions stores sensor data logs temporarily holds program images received over the network interface

Secondary storage Sub-System 4 Mb (512 kB) memory organized as 2048 pages of 264 bytes each Single 2.5V - 3.6V or 2.7V - 3.6V Supply Serial Peripheral Interface (SPI) Compatible 20 MHz Max Clock Frequency Two 264-byte SRAM Data Buffers – Allows Receiving of Data while Reprogramming the Flash Memory Array Low Power consumption – 4 mA Active Read Current Typical – 2 μA CMOS Standby Current Typical AT45DB041B

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

Power management Sub-System Functions regulate the system’s supply voltage

Power management Sub-System (Mica) Maxim1678 DC-DC converter provides a constant 3.0V supply 3 V A solid 3V supply is required for radio operation Lower voltage can be used to conserve energy when the radio is not in use Battery produces energy between 3.2V and 2.0V In an alkaline battery more than 50% energy lies below 1.2 V Converter takes input voltage down to 0.8V and boosts it to 3.0V Ref. 3

Power management Sub-System (Mica2/Z) LM 4041 (precision voltage reference ) Calibrate the battery voltage

Logical architecture Processing RF Communication Power management Secondary storage I/O Sub-system

Communication Sub-System Functions Transmit and receive data wirelessly Coordinate with other nodes

Communication Sub-System implementation MICA Radio TR 1000 modulates-demodulates bit Send data to processor bit by bit AVR (Atmega 103L) Protocol proccesing Transmission power controler DS 1804 Hardware accelerators Serialization accelerator Timing accelerator What is it? Why do we need them?

Hardware Accelerators Application Controller Serialization Accelerator Timing Accelerator M E O R Y I/O B U S RF Transceiver I/O alone - recorded a maximum bandwidth of 10Kbps I/O with hardware accelerators - we have been able to reach speeds of 50 Kbps Ref. 4

We are using hardware accelerators for: Overview We are using hardware accelerators for: SYNCHRONIZATION BIT TIMING BIT SAMPLING each hardware accelerators has been built out of standard microcontroller functional units and rely on I/O programmed to detect start symbol Ref. 4

Hardware Accelerators Timing Accelerator - automatically captures the exact timing of the edge transition of the timing pulse - incoming signal is automatically sampled every .25 us - detection of the start symbol gives us an indication of when the timing pulse will arrive - once the timing information is captured, software then uses it to configure a serialization accelerator that automatically times and samples the individual bits Ref. 4

Synchronization Accelerator Hardware Accelerators Synchronization Accelerator -captures exact timing of incoming packet (within one clock cycle – 250ns) during the synchronization phase of packet reception -information available to application software Ref. 4

Communication Sub-System implementation MICA 2 Radio CC1000 Modulation demodulation Hardware coding-decoding (Menchester) Hardware synchronization Send data to processor byte by byte Power control AVR(Atmega 128L) Protocol processing No need of hardware accelerators No need of DS1804

Communication Sub-System implementation MICA z Radio CC2420 (802.15.4 ZigBee) Send data to processor in packets Modulation, demodulation Protocol processing Synchronization Coding, decoding Error detection, corection Acknowledgements No need of MCU in protocol processing

Resistance to voltage supply variations- no need of DC-DC converter Communication MICA MICA 2 MICA z TR 1000 CC 1000 CC 2420 Radio frequency [MHz] 433/915 315/433/915 2400 to 2483.5 Max data rate (kbps) 40 (115,2) 38,4 (76,8) 250 RX power (mA) 3,8 9,6 19,7 TX power (mA) 12 25 17,4 Powerdown power(μA) 0,7 0,2 1 Turn on time (ms) 0,02 1,5 1,2 Modulation ASK FSK DSSS-O-QPSK Receive sensitivity -95 dBm -101 dBm -94 dBm Outdoor range To 92 m To 305 m 75 m to 100 m Multichannel no yes Resistance to voltage supply variations- no need of DC-DC converter

Radio sub-system architecture Application controller TR 1000 Serialization accelerator Timing accelerator Transm. Power Control + Felxibility + Direct access to signal strength + Rich interface + Wide filed of decisions for programmist -transmission speed limited by processor speed - neccesity of low level programming

Radio sub-system architecture Application controller CC 1000 + hardware support for synchronization and coding/decoding -limited flexibility

Radio sub-system architecture CC2420 Application controller lack of felxibility + easy to programme + 802.15.4 MAC hardware support + 802.15.4 MAC hardware security

Architecture -summary

Mica2 Architecture MicaZ Architecture Mica Architecture Atmega 128 L CC2420 transceiver MicaZ Architecture CC1000 radio transceiver Atmega 128 L Mica2 Architecture Mica Architecture Ref. 3

Sensing Sub-System

Sensing Sub-System Functions Different types of sensors Sampling physical signals/phenomena Different types of sensors Photo-sensor Acoustic Microphone Magnetometer Accelerometer Sensor Processor Interface 51 Pin Connector ON-OFF switches for individual sensors Multiple data channels Ref. 1

Other sensor boards Basic Sensor board Ultrasonic transceiver – Localization Used for ranging Up to 2.5m range 6cm accuracy Dedicated microprocessor 25kHz element Basic Sensor board Light (Photo), Temperature, Acceleration, Magnetometer, Microphone, Tone Detector, Sound Ref. 1

Operating system

Operating system The Mica hardware platform has been designed to support the TinyOS execution model TinyOS is an event based operating system TinyOS allows for an application designer to select from a variety of system components in order to meet application specific goals.

Communication phases

Cost of checking = (radio on time) * (radio power consumption) RF Wakeup - it is necessary to put a collection of nodes to sleep for a long period of time - a radio signal is used to wake the nodes - RF based wake-up protocol - nodes have to periodically turn on the radio and check for wakeup signal Cost of checking = (radio on time) * (radio power consumption) -power consumption of the radio times the time the radios is on Power consumption = (checking frequency) * (cost of checking) -frequency of energy used each time it checks for the signal times the the check Avarage wakeup time = ½ (checking period) = 1/(2* checking frequency) -minimize the time a radio must be turned on each time a node checks for the wakeup signal -minimize the checking frequency Ref. 4

Localization RF localization : - radio – additional sensor - radio - analog sensor to detect the strength of an incoming signal automatically determine the physical position of members central controller can look at the signal strength of each individual bit as well as the level of the background noise -sender helps the receiver determine the reception strength more accurately. Acoustic localization -an alternative to RF localization -more accurate Ref. 4

Encoded data to be Transmitted Wireless Communication Phases Transmit command provides data and starts MAC protocol. Transmission Data to be Transmitted Encode processing Start Symbol Transmission Encoded data to be Transmitted MAC Delay Transmitting encoded bits Preamble Radio Samples Bit Modulations Slow periodic sampling Receiving individual bits Start Symbol Search Synchronization Start Symbol Detecting Reception Encoded data received Decode processing Data Received Ref. 4

Test of Mica, Mica2

Test of MICA, MICA2 Assumptions measuring packet delivery rate The nodes distributed in an ad-hoc manner Impact of the different conditions in the absence of interfering transmissions Nodes placed in a variety of different positions near the ground or elevated, with or without LOS, different levels of obstructions (furniture, walls,trees) distances from 2 to 50 meters Mica 1 Mica 2 Ref. 2

Experiment facts Test of MICA, MICA2 3 different Environments Outdoor habitat reserve Urban outdoor environment Office building 2 Radio type (TR1000, CC1000) 6 different Transmission power settings Mica from –10dBm to 0 dBm Mica2 from –20dBm to +10 dBm Packet size 25, 50, 100, 150 and 200 bytes up to 16 nodes in outdoor and up to 55 nodes in indoor experiments packet delivery data from more than 300,000 packet probes each node transmitting 200 packets Ref. 2

Test of MICA, MICA2 MICA packet MICA MICA MICA MICA MICA

Test of MICA, MICA2 MICA packet MICA MICA MICA MICA MICA

Test of MICA, MICA2 MICA MICA packet MICA MICA MICA MICA

Test of MICA, MICA2 -results Reception rate , distance Outdoor Habitat, Mica 2, low outputpower (-10dBm) Outdoor Habitat, Mica 2, mediumhighoutput power (+1dBm) Reception rates vary drastically from 100% to 0% larger density of data points near the 100% mark for almost all the distance range links with reception rate lower than 50% appear at a larger minimum distance from the source (13 meters) Reception rates vary drastically from 100% to 0% links with reception rate lower than 50% appear at 7m increasing the transmission output power produces an increase in the number of links with good reception rate existence of bad links is not completely eliminated when increasing the transmission output power bad links tend to appear at almost any power setting used Ref. 2

Test of MICA, MICA2 -results reception rate, distance, power lewel Outdoor Habitat, Mica 2 Outdoor Urban Mica 2 Indoor office, Mica 1 General decrease in the reception rate as we increase the distance from the source Assumptions of packet delivery based exclusively on distance from the source can be erroneous in practice Ref. 2

Test of MICA, MICA2 -results Reception rate , distance, the same environment Outdoor Urban, Mica 2, with High Power (+5dBm) Outdoor Urban, Mica 2 with Low Power (-10dBm) Outdoor Urban, Mica 1, with High Power (-1dBm) no significant difference in packet delivery between large and small packet sizes, with only a small decrease in performance for larger packet sizes. Ref. 2

Test of MICA, MICA2 -results, summary General decrease in the reception rate as we increase the distance from the source there is no clear correlation between packet delivery and distance in an area of more than 50% of the communication range Tendency that the higher transmission level the higher reception rate Mica1 gives worse results due to less transmission power Ref. 2

References [1] www.xbow.com Crossbow: „MPR-MIB Users Manual Revision B, June 2006” Crossbow: „Mica, Mica2, MicaZ Datasheet” [2] Alberto Cerpa, Naim Busek and Deborah Estrin „SCALE: A tool for Simple Connectivity Assessment in Lossy Environments” CENS Technical Report # 21 Center for Embedded Networked Sensing, University of California, Los Angeles (UCLA) Los Angeles, CA 90095, USA September 5, 2003 [3] Jason L. Hill, David E. Culler „MICA: A WIRELESS PLATFORM FOR DEEPLY EMBEDDED NETWORKS” [4] Jason Hill and David Culler „A wireless embedded sensor architecture for system-level optimization” [5] Datasheets: Atmel 128l, Atmel 103l, Maxim 1678, RM 4041, DS1804, TR1000, CC1000, CC2420 [6] Joseph Polastre, Robert Szewczyk, and David Culler (Computer Science Department University of California, Berkeley): „Telos: Enabling Ultra-Low Power Wireless Research” [7]M.Sc. Thesis by Martin Leopold: „Power Estimation using the Hogthrob Prototype Platform” [8]Deepak Ganesan, Tom Schoellhammer: „ TinyOS: Platforms and Foundations” [9]Jason Hill (WEBS retreat 1/14/2002): „ MICA Node Architecture”

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