Project Definition

SoNET Summary

1. Background

This paper proposes a delay-tolerant based mobile sensing network called Sonoma County Geo-Sensor Network (SoNET) for monitoring microclimates. The network utilizes distributed nodes with heterogeneous sensing capacity to create a rich collection of ecological data about climatic variations in the country. Using ZigBee-based communication protocols, mobile nodes in SoNET network can exchange data and ensure data penetration to the weather server. Through experimental measurements, in this paper we demonstrate that SoNET can be an effective alternative to deploying expensive individual climate stations or challenging dense sensor networks. We also evaluate the performance of our proposed protocols for data exchange between mobile nodes.

In order to study factors such as population dynamics, mortality, and habitat needs, it is important not only rely on average environmental conditions, but also learn about environmental conditions over narrow spatial gradients, also known as microclimates. Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological elemental measurements in a given region over long periods [12]. Microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term microclimate may refer to areas as small as square feet or as large as a few square miles. In general, climate usually determined on long period of time for a particular time and microclimate is a specific climate conditions according to the topography.Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavily urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and reradiate that heat to the ambient air: the resulting urban heat island is a kind of microclimate. Another contributing factor to microclimate is the slope or aspect of an area. South-facing slopes in the Northern Hemisphere and north-facing slopes in the Southern Hemisphere are exposed to more direct sunlight than opposite slopes and are therefore warmer for longer [1].An example of a region with many diverse microclimates is Sonoma County, located on the coast of the Unites States, state of California. The county, with total area of about 4,500 square km, 10% of it being water, has a large degree of climatic variations and numerous different microclimates. The key contributing factors to the existence of such rich climate diversity are elevation and proximity to the ocean.Microclimates in Sonoma County are typically evident during rainy seasons, when the rainfall can vary between 700 mm to 1500 mm. In summer, weather patterns contribute to high diurnal temperature fluctuation in the county, creating inland daily lows and highs which can be 15-25 °C apart.

2. Project Statement

Comprehensive study of climate diversity and habitat monitoring throughout the Sonoma County cannot simply be extrapolated from a few existing individual climate stations in the region. An alternative approach is deploying dense sensor networks in various areas of interest and habitat patches in the county. In fact, over the past decade there have been many efforts for outdoor deployment of wireless networks for making and recording ecological measurements [2].However, deployment and maintenance of such networks can create daunting technological challenges. For example, such networks must be very power efficient, reliably connected to a cyber infrastructure at all times, and operate under various ranges of environmental stresses.Another approach to study microclimates is to use distributed sensors carried by mobile users. In this paper we introduce a based climate monitoring network implemented around the Copeland Creek in Sonoma County, which is ZigBee-based on the concept of delay-tolerant networking (DTN). We refer to this network as Sonoma County Geo-Sensor Network (SoNET). SoNET network is compromised of many mobile nodes and several stationary terminal nodes. A mobile node is a low-cost light-weight device with heterogeneous sensing capacity, measuring temperature, humidity, pressure, etc., and can be worn by people or animals or can be installed on vehicles (e.g., cars and bicycles). Each mobile node (we also refer to it as the climate pod or cPod) is equipped with a GPS receiver, ZigBee wireless transceiver, MBED microcontroller, MicroSD card, and a rechargeable power module. The ZigBee wireless modules allow communications between individual mobile nodes and mobile/terminal nodes. Thus, cPods can exchange their collected environmental data and pass them on to another cPod, which is more likely to visit a terminal node. Terminal nodes are stationary devices that can communicate with cPods and receive their data. The received data by the terminal node is transmitted to the weather server, which is accessible by individual remote users.In the proposed DTN based network data propagation is achieved through random contacts of mobile nodes. Thus, as environmental data (e.g., temperature and humidity) is measured and collected by individual mobile nodes, it can be propagated to the weather server through various cPods coming in contact with one another. Consequently, through a collective social effort, a very comprehensive weather database can be created, providing rich information about various microclimates around the Sonoma County. Fig. 2 depicts an overview of the proposed SoNET.SoNET uses the general approach of delay-tolerant networking architecture. In this architecture individual mobile nodes convey the measured delay-tolerant ecological data into the weather server. Each mobile node (cPod) functions as a store-and-forward facility. Thus, using the bundle layer [3] all the stored data can be aggregated into one or more bundle messages or simply messages and passed on to another node. The bundle layer allows exchanging messages between different nodes. Thus, a mobile node can act as relay nodes to propagate the data to a terminal node. Note that data exchanges between nodes can only take place when nodes come in contact together. When a message is exchanged, the receiver will assume message custody [4]. Thus, the transmitting node can delete the data upon experiencing limited storage capacity for future measurements.

3. Project Requirements

A.      Hardware:

  • —The node is capable of transmitting data over Ethernet in wired mode  or communication with other nodes or a base-station within proper range
  • —Each node should have a different ID
  • —The node should be waterproof and suitable for outdoor use
  • —The node operates at 12 V DC from a running car
  • —The node records data every specific time interval according to specific internal setup by user
  • —The node erases the stored data after a successful transmission
  • —The node will search for another node with internet connection when it's not online
  • —The node will choose connection with the base-station over any other nodes
  • —Only one connection is allowed between peers at any given time (node-to-node, node-BS, node-to-Internet)
  • —A node can be configured to accept data from other nodes
  • —A node can be configured to transfer data to other nodesAt any given time only one interface can be operational (e.g., Zigbee, WiFi, Ethernet)
  • The GPS module will synchronize the clock of the node after turn on and then the clock will work independently
  • —External antenna may be required for longer range interface
  • —The data is recorded in a text format
  • —A power LED indicates the presence of power into the system
  • —When transmitting data the node stops logging new data
  • —The node supports up to 5 analog sensors and 2 digital sensors and a GPS
  • —The node is capable of transmitting data while moving
  • —The dimensions of each node is approx. 15 cm * 20 cm * 20 cm
  • —A LCD over the box displays the status of the node
  • —Some buttons and a joystick over the box provide user interface
  • —The node can be disabled by an on/off switch
  • —The LCD indicates a message upon completing data transfer
  • —The LCD also displays current sensor status, readings, battery status and memory usage 
  • The size of the LCD will be 60 characters per line * 3 lines
 Node ID      Working: Yes/No/Transmitting       Memory Used(%)      Connection: No/wired/wireless
GPS Coordinates:                                                    Time: hh:mm MM/DD/YYYY

Current Sensor Reading:

B.      Software:

B.1 Receives the data sent from the sensors over the internet and stores them in the database
B.2 Outputs the data to the screen via web browser
Provides remote access to the database
B.4  Provides interface between the database and Google Map
B.5 Capability to increase and decrease the scale of the map
B.6 Capability to flag potential errors in the database
B.7  These attributes below will be recorded by the node and send to the database

Attribute 1
 Attribute 2  Attribute 3 Attribute 4
Attribute 5
 Attribute 6  Attribute ...Attribute ...
 Recoded Time

Transmitted by ID

C.  Future Work:

C.1  Powered by solar panels
C.2  A web-cam takes pictures then upload to the server
C.3  Using RFID instead of Zigbee
C.4  The sensor can be put on a robot instead of a car
C.5  Replacing some parts to lower the cost
User-interface friendly
C.7  Add more sensors to gather information for analysis
C.8  Apply a routing protocol in the sensor network

4. Work Breakdown

Phase 0

- Project schedule. Project requirement and statement.

- Draw a high-level diagram.

- Create a project website.

- Do research on different wireless technologies to find an appropriate one.

Phase 2

- Choose a Linux system board from the market.

- Choose a wireless interface card.

- Program a Linux embedded system to exchange data between the sensor and the
base station wirelessly.

Phase 3

- Duplicate a copy of the sensor.

- Program a Linux embedded system to exchange data between two sensors then
one of them send data to the base the station.

Phase 1

- Choose a microcontroller, sensors and datalogger to collect and store the data. Decide
the way of the data being stored.

- Program a microcontroller to collect temperature, humidity, etc.

- Program a microcontroller to collect GPS location data.

- Store the data in the datalogger.

Phase 4

- Decide the os of the server and the software will be used.

- Google map interfacing. Show current data and location on the Google map.

Phase 5

- System test.

- Work on documentation and paper.


5. Risks


- All electrical device may have a risk of malfunction

- Wireless network may be attacked

- Lost information or bit error during the transmition

  - Lost power during the operation

  - Drivers for the board may not be found and need to buy a new one

  - Communication problems

  - The database maybe not working because of lack of expertise

  - The worst case would be collecting data only

  - Over-budget

  6. Similar Project 

  -  Google Street View camera car tagged with GPS sensor, stalked around Berlin

  -  Iphone MotionX