1. Wireless in-situ Road Condition
Sensor Network
Qiang Chen, Lirong Zheng & Frederik Jonsson
iPack Vinnex Center,
Royal Institute of Technology,
Stockholm, Sweden

2. Why in-situ Road Condition
Wireless Sensing?
1. Gives almost real time monitoring of road
condition
2. Real time alarming is possible
3. Via commercially available wide area wireless
network, one can place such measurement set-up
virtually anywhere and anytime if needed
4. If needed data can be either send back via wireless
WAN or stored in memory device

3. Application Requirements
1. Temperature (-40C - +60C)
2. Humidity (0-100% RH)
3. Vibrations up to ~kHz
4. Strain

4. System Architecture
- An Overview
Wide Area Network Central DB Client Enterprise Network
WSN
Server
WEB
Server
Technician
Monitoring and Analyzing
Fresh Food Tracking
Central
Server
Sensor Area Network
Alarming
Fresh Food Tracking
Road End User
Operation Center On-shelf Query Tracking and Localization
Master Sensor Node Slave Sensor Node

5. System Architecture -1
(First Layer Wireless Communications between
Master Sensor Node and Central Server and End Users)
Master
Sensor
GPS
Node
GSM/GPRS/3G Wireless
Wide Area Network
Real Time
System
Tracking
Application
Online Web
(Internet)
Text Message
ALARM Data Statistics
& Analysis
E-mail
Central Server
& Database

6. System Architecture -2
(Second Layer Wireless Communications between
Master Sensor Node and Slave Nodes)
Master Sensor Node
Slave Sensor Nodes
Power Management
4.5V
(placed inside road and road
Step-up 5V
Battery DCDC LDO 3.8V shoulder)
Converter
LDO 3V
Road Coin
Battery
3.3V CPU and Backup
LDO Memory
Sensors
JTAG
Temperature
Sensors CPU and Backup Memory Communication Module sensor
CO2 Signal
Sensor Interface JTAG
RX (UHF 900MHz) Humidity
Communication Module CPU
TX (I-UWB) sensor
Oxygen Analogue GSM(GPRS)/GPS
Microcontroller
Sensor MUX Module Accelerometers
2.4GHz RFID as Memory
Ethylene Signal SD Memory RX (UHF 900MHz) communication Link
Sensor Interface card TX (I-UWB)

7. System Operational Flow
User Operations Operation Center Sensor Node
Service
User
1 Registration
Registration
Wakeup
Manager
Management Runtime
Service Selection Service Sensor Node
Configuration API
2 and Specification Authentication DB Configuration
Manager Manager
Sensor Data On-site Data
Collection Processing
3 User Login
Driver Firmware
Data Sensor Sensor Node Data Uploading
Monitoring and
4 Tracking
Visualization DB Data Collector API
Engine
Alarming API
Alarming
Alarming
Manager
Controlling API
Control
Controlling
Manager Sensor Node Executive
Controller Driver
Data
5 Data Sharing Sharing Sleep
Engine
Sensor Node Sensor Node
Web Function Web Service
API Function

8. System Implementation
-Sensor Selection
1. T & RH sensor to meet requirement
2. Vibration: accelerometer up to 5g with analog
output for frequency>1KHz
3. Strain gauge requires special technique, not
integrated yet

9. System Implementation
-Database
Sensor DB
Management DB
PK
User Infor
UserID
SensorAllocation
Node Configuration
PK NodeID
SensorSelectT
Temperature
PK
PK
NodeID
Time
…...
UserName
UserPassword SensorSelectRH Value
PK UserID ...
... PK ServiceID SensorPeriodT WAN Positioning
PK NodeID SensorPeriodRH GPS
ServicePackage ... PK NodeID
StartTime UpLimitT PK NodeID PK Time
PK ServiceID FinishTime DownLimitT PK Time
Status UpLimitRH ContryID
Price ... DownLimitRH Longitude AreaID
payable ... Latitude CellID
... SmsIfAlarm altitude BaseStationID
UploadToIP Distance
UploadToPort Angle
SmsToNumber
AlarmPeriod Event Log
AlarmEnabled
PK NodeID
UploadContry
PK Time
SimCardID
SoftwareVersion
Type
...
Message
Availability

10. System Implementation
-Hardware Architecture
Micro Panel 2.4G RF H&T Accele.
CO2 GPS
-SD Socket Tranceiver Sensor
Sensor WAN
Accele. RTC
Adapter
RTC 2.4G RF
O2 MCU
2.4G Detector
Sensor MCU
RFID
...
Sim Card Reader IR-UWB
...
Ethy Tx
Charger Power
Sensor Jack
Controller Power Management
Management IR- Button Array
...
H&T Li-ion Array Battery
UWB
Sensor Battery
MSN-SEN MSN-MAIN board MSN-SAN SSN board
board board

11. System Implementation
-Hardware Example

12. System Implementation
-Acceleration Data Compresion
2
acce.(G)
1
0
2 2
-1
D waveform 1650 1700 1750 1800 1850 P waveform
1
acce.(G)
1
acce.(G)
samples
0 0
2
-1 -1
A waveform 1650 1700 1750 1800 1850
acce.(G)
1650 1700 1750 1800 1850 1
samples samples
0
-1
1650 1700 1750 1800 1850
samples

13. System Field Test Results
(for Another Application)

14. Field Test
-Vibration
2.5 1.5 2.5 1.5 1.5
2 1 2 1 1
1.5 0.5 1.5 0.5 0.5
acce.Z ( G )
acce.X ( G )
acce.X ( G )
acce.Y ( G )
acce.Y ( G )
1 0 1 0 0
0.5 -0.5 0.5 -0.5 -0.5
0 -1 0 -1 -1 Shock
-0.5 -1.5 -0.5 -1.5 -1.5
0 5 10 15 0 0 5 5 10 10 15 0
15 0 5 5 10 10 15
time (50ms) 5 time (50ms) (50ms)
time 5 5 time (50ms)
time (50ms) 5
x 10 x 10 x 10 x 10

15. Conclusion
1. An in-situ road condition monitoring system based
on wireless sensor network and RFID technologies
is presented.
2. Sensor node placed inside road/road shoulder
need special design, need further improvement
3. Battery-less sensor node solution based on energy
harvesting e.g., piezo-electric effect (vibration) and
thermo-electric effect (temperature gradient) and/or
solar cell
4. To integrated strain gauge requires special
interface circuits since the gauge is based on
Winston-bridge principle

16. Thank You