WISENET is a wireless sensor network that monitors the environmental conditions such as light,
temperature, and humidity. This network is comprised of nodes called “motes” that form an ad-
hoc network to transmit this data to a computer that function as a server. The server stores the
data in a database where it can later be retrieved and analysed via a web-based interface. The
network works successfully with an implementation of one sensor mote.
The last few years have seen the emergence of numerous new wireless technologies, some of
which (for example IEEE 802.11b, Bluetooth, etc...) have reached the market recently. While the
general trend is to offer higher and higher data rates, there are many existing and new
applications that do not require such a high bandwidth, but would strongly benefit from a
wireless communication link. Examples of such applications are wireless sensor networks. In this
perspective, the Microelectronics Division has launched a project called WISENET. Its main
objective is to develop a low-power wireless ad-hoc network made of many distributed micro-
sensors that are energetically autonomous (usually battery operated) and able to communicate
amongst them and with the external world. WISENET will enable the monitoring and the control
of physical and environmental parameters for a variety of applications spanning the home, the
office, the clinic, the factory, in vehicle, over metropolitan area, and the global environment. For
example, WISENET will monitor security and safety in the future homes and offices
The technological drive for smaller devices using less power with greater functionality
has created new potential applications in the sensor and data acquisition sectors. Low-power
microcontrollers with RF transceivers and various digital and analog sensors allow a wireless,
battery-operated network of sensor modules (“motes”) to acquire a wide range of data. The
TinyOS is a real-time operating system to address the priorities of such a sensor network using
low power, hard real-time constraints, and robust communications.
The first goal of WISENET is to create a new hardware platform to take
advantage of newer microcontrollers with greater functionality and more features. This involves
selecting the hardware, designing the motes, and porting TinyOS. Once the platform is
completed and TinyOS was ported to it, the next stage is to use this platform to create a small-
scale system of wireless networked sensors.
3. System Description
There are two primary subsystems (Data Analysis and Data Acquisition) comprised of three
major components (Client, Server, Sensor Mote Network).
3.1 Primary Subsystems
There are two top-level subsystems –
1. Data Analysis
2. Data Acquisition.
3.1.1 Data Analysis
This subsystem is software-only (relative to WISENET). It relied on existing Internet and web
(HTTP) infrastructure to provide communications between the Client and Server components.
The focus of this subsystem was to selectively present the collected environmental data to the
end user in a graphical manner.
3.1.2 Data Acquisition
The purpose of this subsystem is to collect and store environmental data for later processing by
the Data Analysis subsystem. This is a mix of PC & embedded system software, as well as
embedded system hardware. It is composed of both the Server and Sensor Mote Network
3.2 System Components
System components are Client, Server, and Sensor Mote Network.
The Client component is necessary but external to the development of WISENET. That is, any
computer with a web browser and Internet access could be a Client. It served only as a user
interface to the Data Analysis subsystem.
Figure 1: Client Components Inputs/Outputs
The Server is a critical component as the link between the Data Acquisition and Data Analysis
subsystems. On the Data Analysis side, a web (HTTP) server hosting a web application. When a
page request came in, the web server executes the web application, which retrieved data from
the database, processes it, and returns a web page that the web server transmitted to the Client.
For the Data Acquisition system there is a daemon (WiseDB) running to facilitate communication
with the Sensor Mote Network.
Figure 2: Server Components Inputs/Outputs
This daemon is responsible for collecting raw data packets from the Sensor Mote Network. These
packets are then processed to convert the raw data into meaningful environmental data. This
processed data is then inserted into the database. Thus the database is the link between the
Data Analysis and Data Acquisition subsystems. The Server also had the potential to send
commands to the Sensor Mote Network (via the gateway mote), although this functionality was
not explored in WISENET.
It should be noted that since the SQL database connections can be made via TCP/IP, only the
web server and web-program (see figure 4) needed to be located on the same physical machine.
The web server, the database, and WiseDB could all be on different physical machines connected
via a LAN or the Internet. This allows a flexible Server component implementation that is useful
during WISENET development.
Figure 3: Server Components Mote Diagram
3.2.3 Sensor Motes
The primary focus of WISENET is the development of the Sensor Mote Network component. It is
the component responsible for collecting and transmitting raw environmental data to the Server.
There is also the potential for the motes to receive commands from the Server, although that
functionality may not be implemented in WISENET. Uses for this feature would include server-
based synchronization and wireless network reprogramming.
Figure 4: Sensor Mote Component Inputs/Outputs
This component consists of two parts. The first is the sensor mote. The primary purpose of the
sensor mote is to collect and transmit raw environmental data. When not doing this, it went into
a low-power idle mode to conserve energy. Another aspect of the sensor motes involved ad-hoc
networking and may be for multi-hop routing.
The gateway mote is the second part of the Sensor Mote Network. Its purpose is to serve as the
contact between the Server and the Sensor Mote Network and deliver all the data packets to
WiseDB. In theory both standard and gateway motes could be implemented on the same
hardware PCB and with the same software. For WISENET, however, resource and time
constraints necessitated the use of slightly different hardware and software configurations for
gateway versus standard motes, as described below.
The selection of components for the sensor motes is a critical process in the development of
WISENET. Great functionality and low power are two of the highest priorities in evaluating the
fitness of both the microcontroller and the sensor candidates. WISENET is introduced to the new
state-of-the-art Chipcon CC1010 microcontroller with integrated RF transceiver. After a little
research it was decided the CC1010 would make the perfect microcontroller.
It had the following feature list:
1. Optimized 8051-core: Most of the early embedded microcontrollers use processor
architectures that were taken from eight bit microprocessors. This is the worst way because the
processor addressing is usually not optimized for accessing local hardware registers and their
individual bits. Two devices which buck this trend are the Microchip PIC and the Intel 8051. The
8051 was designed from the perspective of what a microcontroller is and what it has to do. It
included in the basic design was 4K of Read Only Program Memory, 128 Bytes of Internal RAM, a
USART and 32 I/O Pins. The only major problem with the 8051 architecture is the twelve clock
cycles per instruction cycle. This has made the 8051 appear non-competitive to other
microcontrollers which can have as few as one clock cycle per instruction cycles.
2. Active (14.8 mA), Idle (29 _A) and sleep (0.2 _A) power modes
3. 32 kB flash memory: Flash memory is a form of EEPROM (Electrically-Erasable Programmable
Read-Only Memory) that allows multiple memory locations to be erased or written in one
programming operation. Normal EEPROM only allows one location at a time to be erased or
written, meaning that flash can operate at higher effective speeds when the systems using it
read and write to different locations at the same time. All types of flash memory and EEPROM
wear out after a certain number of erase operations. Flash memory is made in two forms: NOR
flash and NAND flash.. This makes it suitable for storage of program code that needs to be
infrequently updated, as in digital cameras and PDAs. However its I/O interface allows only
sequential access to data. This makes it suitable for mass-storage devices such as PC cards and
various memory cards, and somewhat less useful for computer memory.
4. 2 kB +128 bytes SRAM
5. Three channel 10-bit ADC: 10bit Analog to Digital Converter (ADC) uses a four wire SPI
interface. The 8515 processor has SPI hardware support built in and using it would have been
fast with minimum software overhead. 10 bits is pretty high resolution. To avoid digital noise on
the analog signals, added a separate +5V supply (78L05) devoted just to the ADC and the
photodiodes used as inputs. The ground for all of the above was tied into one point where the
power came into the regulator. With minimal bypass capacitors on the ADC inputs easily get
6. Four timers / Two PWM's: There are two essentially different versions of PWM: the original
very lightweight window manager, and the newer Ion-based PWM2. PWM was the first window
manager to implement "tabbed frames" or the back then unique feature allowing multiple client
windows to be attached to the same frame. This feature helps keeping windows, especially the
numerous x-terms, organized. A look at the screenshots below might clarify the idea. Being a
lightweight window manager with emphasis on usability, PWM discards some features common
in window managers these days: only window shading in lieu of iconification is supported, there
are no close and other window buttons (these actions are available conveniently through a
menu), simple and elegant look instead of pixmapped themes, et cetera. PWM does have
workspaces, menus and Window Maker dockapp support. It has pretty good keyboard support
and almost all the functionality is configurable.
7. Hardware DES encryption/decryption
8. Hardware random bit-generator
9. Fully integrated UHF RF transceiver (433 MHz / 868 MHz nominal): The wireless transceiver
contains at least two physical links, each with its own transmitter-receiver circuit in addition to
digital and analog signal processing circuits to communicate with other wireless units using
Orthogonal Frequency-Division Multiplexing (OFDM) protocol. The design approaches address
the issues of noise interference between analog and digital subsystems, noise interference
between two links on the same chip, and high-frequency self-test, measurement of functional
parameters (SNR, jitter, etc.), and interface between on-chip test facilities and external low-cost
testers. The methodology is validated by a complete design, fabrication, and test of a case study
selected in consultation with industry partners.
-> Programmable output power (-20 to 10 dBm)
-> Low current consumption (11.9 mA for RX, 17.0 mA for TX at 0dBm)
-> RSSI output that can be sampled by the on-chip ADC
WISENET includes a socketed evaluation board (CC1010EB) and two evaluation modules
(CC1010EM). CC1010 - The industry's first truly complete RF System-on-Chip solution! On a single
die, the award winning 300 to 1000 MHz CMOS CC1000 RF Transceiver has been integrated with
an industry standard 8051 microcontroller core The CC1010 integrates a very low-power 300 to
1000 MHz RF transceiver and a 8051-compatible microcontroller that has 32 kB in-system
programmable Flash, hardware DES encryption/decryption and a three channel 10-bit ADC. This
means only a few external passive components are necessary to make a powerful embedded
system with wireless communication capabilities, sensor interfacing possibilities and a lot of
processing power. The evaluation board provided access to all of the analog and digital pins on
the CC1010, as well as two serial ports, a parallel programming port, RF network analysis ports,
and other peripherals. Each evaluation module featured the CC1010, RF network hardware, an
antenna port, and an analog temperature sensor. The modules connected to the evaluation
board via two sockets. These sockets also allowed the possibility of designing a custom
WISENET is designed to measure light, temperature, and humidity. There are many digital
temperature sensors available, but there is a much smaller selection of digital humidity and light
sensors. A larger selection of analog sensors are available; however, analog sensors tended to
require more power and be less precise than their digital counterparts, in addition to requiring
more complex circuitry. For these reasons, digital sensors are given higher priority. Two new
sensors provided the required functionality. First, Sensirion released the SHT11, a digital
temperature and humidity sensor with ultra-low power consumption (550 Micro A while
measuring, 1 Micro A when in sleep mode), a 14 bit analog to digital converter, and the desired
accuracy (±5% relative humidity, ±3ºC). It also featured a simple serial interface. The light sensor
chosen was the Texas Advanced Optoelectronics Solutions (TAOS) TSL2550 ambient light sensor
with SMBus interface. This sensor also featured ultra-low power (600 MicroA active, 10 MicroA
power down), a 12-bit analog to digital converter, and dual photo diodes. The TSL2550 uses both
photo diodes to compensate for infrared light and to produce a measurement that approximates
the human eye response.
The final stage of hardware design involved creating the Add-on module. The WISENET Add-On
Module has the two digital sensors described above. The Sensirion SHT-11 humidity and
temperature sensor has a 2-wire proprietary serial interface. The TAOS TSL2550 digital light
sensor uses an SMBus serial interface. SMBus is a standardized 2-wire serial interface. The layout
must be carefully designed such that the light, temperature and humidity sensors does not
underneath the evaluation module when it is plugged into the board, which would make them
5. Software Design Shelf Products
The server using for WISENET should have four commercial off the shelf applications installed on
it that worked together to create the Data Analysis portion of the Server component.
Apache, MySQL, and PHP are open-source products freely available on the Internet. In addition,
Chart-Director the trial version of the commercial application Chart-Director was used.
Apache is a standard web-server, which makes a web document available on the Internet. The
Apache http server is a powerful, flexible, implements the latest protocols is highly configurable
and extensible with third-party modules can be customised by writing 'modules' using the
Apache module API provides full source code and comes with an unrestrictive license runs on
Windows NT/9x, Netware 5.x and above, OS/2, and most versions of Unix, as well as several
other operating systems is actively being developed encourages user feedback through new
ideas, bug reports and patches implements many frequently requested features, including:
DBM databases for authentication: It allows you to easily set up password-protected
pages with enormous numbers of authorized users, without bogging down the server.
Customized responses to errors and problems: Allows you to set up files, or even CGI
scripts, which are returned by the server in response to errors and problems, e.g. setup a
script to intercept 500 Server Errors and perform on-the-fly diagnostics for both users
Multiple Directory Index directives: Allows you to say DirectoryIndex index.html,
index.cgi, which instructs the server to either send back index.html or run index.cgi when
a directory URL is requested, whichever it finds in the directory.
Unlimited flexible URL rewriting and aliasing: Apache has no fixed limit on the numbers
of Aliases and Redirects which may be declared in the config files. In addition, a powerful
rewriting engine can be used to solve most URL manipulation problems.
Content negotiation: The ability to automatically serve clients of varying sophistication
and HTML level compliance, with documents which offer the best representation of
information that the client is capable of accepting.
Virtual Hosts: A much requested feature, sometimes known as multi-homed servers. This
allows the server to distinguish between requests made to different IP addresses or
names (mapped to the same machine). Apache also offers dynamically configurable
Configurable Reliable Piped Logs: You can configure Apache to generate logs in the
format that you want. In addition, on most UNIX architectures, Apache can send log files
to a pipe, allowing for log rotation, hit filtering, real-time splitting of multiple hosts into
separate logs, and asynchronous DNS resolving on the fly.
PHP is a web programming language, which allows dynamic web-pages. It should also be
designed to use along with a database and included many built-in functions for interfacing with
MySQL is a database that can contain any type of data and is accessed by a TCP/IP (Internet) call.
Chart-Director is a program that generates a graph from raw data. It is available in many
languages such as PHP, ASP, C++, and others. General features are:
Fast and Efficient: Multi-threaded architecture specially designed for the demanding
requirements of server side usage.
Flexible: Object oriented API allows you to control and customize chart details, enabling
you to design the charts you want.
Comprehensive Chart Styles: Pie, bar, line, spline, step line, trend line, curve-fitting,
inter-line colouring, area, scatter, bubble, box-whisker, HLOC, candlestick, simple Gantt,
radar, polar. XY axis swapping (rotated charts) and 3D effects.
Layer Architecture: Synchronized chart layers allow chart styles to overlay for arbitrary
combo chart and special effects. For example, box-whisker layers can be used to add
error symbols to any XY chart styles, and scatter layers can be used to highlight data
points with custom symbols.
CDML: The innovative Chart Director Mark Up Language (CDML) technology allows rich
formatting of text with embedding icons and images. CDML is supported in all
ChartDirector text positions, including chart titles, legend keys, axis labels, data labels,
Advanced Colour System: In additional to ARGB colours (true colour with alpha
transparency), all objects in ChartDirector can be painted using "magic colours" - colours
that depend on position. Generates image maps to support tool tips and other mouse
interactions. Ideal for "drill-down" capabilities. Tool tips are customizable and can include
custom text or data. Image maps are "open-ended" and can include user-defined regions,
such as for company logos, icons and buttons.
Internationalization: Unicode characters support. Configurable number and date/time
6. Software Components-Custom
WISENET is also composed of three custom software components- The Web program, WiseDB,
and a port of TinyOS.
WISENET’s web program was written in PHP and utilized the Chart-Director charting software.
The web application queried MySQL database for the data in the requested date range, then we
use a Chart-Director to generate a graph of that data.
WiseDB is the custom software component that interfaced with the Sensor Mote Network via a
serial link to the gateway mote and with the MySQL database via a TCP/IP link to the MySQL
server application. Already we know about how WiseDB interacted with the rest of the system.
WiseDB was written in C++ and utilized two open-source API’s (application programming
The final custom software component involves porting TinyOS to the CC1010-based hardware
platform described in the Hardware Design section. As previously mentioned, TinyOS is a real-
time operating system designed for use in sensor network applications where low-power, limited
resources and hard real-time constraints are critical parameters. After implementing all the
software and embedding in a single system other important goal of WISENET is to completely
replace the lower-layer functionality to permit existing higher-level components and applications
to be immediately implemented on the new hardware platform without modification.
7. Future Work
There are a number of future extensions for this WISENET. A few of them are-
We can expand the sensor mote network by adding more motes. This would allow the
development and testing of advanced network-layer functions, such as multi-hop routing.
By creating a new PCB design that integrates the CC1010EM design with the sensors and
power hardware on a single-board another interesting feature can be developed or adopt
a standard expandable plug-in sensor interface in both hardware and software.
In researching alternative energy sources to extend mote battery life. Possibilities include
solar cells and rechargeable batteries.
Wireless sensor networks are getting smaller and faster, increasing their potential applications in
commercial, industrial, and residential environments. WISENET, as implemented, represents one
commercial application. However, the limit of applications depends only upon the sensors used
and the interpretation of the data obtained. As the technology improves and new low-power
digital sensors become more readily available, motes will increase functionality without
increasing power consumption and will expand the wireless sensing market.
. http://www.radiowirelessweek.org/wisnet/ Time-23-01-2014 at 8pm.
. http://www.wisenet.uu.se/links.html Time-24-01-2014 at 7.30pm
. http://www.chipcon.com/files/AN_017_Low_Power_Systems_Using_The_CC1010_1_1.html Time
. http://cegt201.bradley.edu/projects/proj2003/wisenet/ Time 29-01-2014 at 10pm