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

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

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

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

5. 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

6. System architecture

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

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

9. Processing sub-system
Functions
Application execution
Resource management
Peripherial interaction

10. 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

11. 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

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

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

14. 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

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

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

17. 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

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

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

20. 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

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

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

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

24. 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?

25. 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

26. 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

27. 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

28. 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

29. 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

30. Communication Sub-System implementation MICA z
Radio CC2420 ( 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

31. 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
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

32. 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

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

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

35. Architecture -summary

36. 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

37. Sensing Sub-System

38. 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

39. 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

40. Operating system

41. 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.

42. Communication phases

43. 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

44. 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

45. 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

46. Test of Mica, Mica2

47. 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

48. 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

49. Test of MICA, MICA2
MICA
packet
MICA
MICA
MICA
MICA
MICA

50. Test of MICA, MICA2
MICA
packet
MICA
MICA
MICA
MICA
MICA

51. Test of MICA, MICA2
MICA
MICA
packet
MICA
MICA
MICA
MICA

52. 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

53. 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

54. 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

55. 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

56. 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”

57. Thank you for your attention
Do you have any questions?