26-04-2012, 12:20 PM
battery-less power supply with dynamic duty cycle for wireless sensor networks
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Abstract
In this demo, we introduce ATON, a batteryless
power management system particularly suitable for
wireless sensor networks to be deployed outdoors. The
main physical elements of ATON are a set of small-sized
solar cells for energy harvesting and an ultracapacitor for
power storage. The power consumption is managed by
adapting the duty cycle of the radio to the
charge/discharge cycle of the ultracapacitor. The main aim
of the demo is to show the feasibility of ensuring the longlasting
operation of a low-power sensor node, such as the
Telosb, by properly adapting the duty cycle of the radio of
the wireless node to the charge/discharge cycles of the
ultracapacitor.
Index Terms— power management, sensor networks
supercapacitors, energy harvesting.
I. INTRODUCTION
Power management is nowadays one of the main challenges
in the deployment of wireless sensor networks. Even though
several projects have put forward novel energy harvesting
technologies and alternative energy storage devices [1][2][3],
the development of a solution ensuring the long-lasting
operation of sensor nodes requires smart management
strategies. In this demo, we introduce ATON, a battery-less
power supply with dynamic duty cycle for wireless sensor
networks.
II. ATON
A new battery-less system supply based on harvesting
techniques has been designed for low power wireless sensor
networks. The proposed system is made up of: 1) a set of lowpower
solar cells connected in series forming a photovoltaic
panel of 60x40mm with an optimum voltage work of 3.3V and
24mA of current; 2) a supercapacitor or high density capacitor
This work has been supported, in part by, the Spanish Ministry of Science and
Innovation under grants CONSOLIDER Ingenio-2010 CSD2006-00046 and
TIN2006-15516-C04-02 and by the Regional Council of Science of Castilla
La Mancha (Spain), under grant numbers PBI08-0273-7562 and PBI08-0228-
9935.
as energy storage; 3) a power control unit responsible of
properly coupling the supercapacitor voltage to the sensor
node electrical characteristics; and 4) a filter stage connected
to Telosb mote to avoid electromagnetic interferences and
possible noise produced by the power unit.
Figure 1 shows the diagram of the electronic components of
ATON. The power control unit, with the filter stage, is
responsible for supplying the energy that the sensor node will
consume. The sensor node continuously monitors the stored
energy in the supercapacitor. This information is used for
adapting the duty cycle of the radio system.
Figure 1. Circuit diagram of ATON
Figure. 2. Telosb mote with ATON
The novel advantage of this system is the fact that it has no
batteries. In this way, we avoid the problem of battery
replacement which in many instances may be prohibitive [4].
Demo Abstract: ATON, A battery-less power
supply with dynamic duty cycle for wireless
sensor networks
P. Díaz, T. Olivares, L. Orozco and F. Royo
Albacete Research Institute of Informatics
Universidad de Castilla-La Mancha
pedrodiaz, teresa, lorozco, froyo[at]dsi.uclm.es
III. DEMO CONFIGURATION
A. Testbed setup
The testbed setup will consist of two Telosb motes. The first
mote will act as data sink and it will be further connected to a
laptop computer which will act as server for data capture and
visualization. The second Telosb which will be powered up by
ATON with a 1-F supercapacitor, will be periodically
reporting via the wireless channel the charge of the capacitor
as well as the power consumption due to the node activity,
mainly due to the radio system. In order to charge the
supercapacitor, a lamp will be used as light source. As already
stated, the data being captured will be sent to the laptop for
storage and data visualization. The packet length of the data
being transmitted is 12 bytes long. Figure 3 depicts the
graphical user interface of the application enabling the
visualization of the supercapacitor status, i.e., load.