Two Papers Accepted for Publication in IEEE Transactions26th September 2011
We have recently had two papers related to our work on Energy Harvesting electronics accepted for publication in the IEEE Transactions on Circuits and Systems. Both publications are a result of the EPSRC project on 'Holistic Energy Harvesting'.
Our paper on supercapacitor modelling
The first paper, 'Accurate Supercapacitor Modeling for Energy-Harvesting Wireless Sensor Nodes' investigates supercapacitors, often used in energy-harvesting wireless sensor nodes (EH-WSNs) to store harvested energy. Until now, research into the use of supercapacitors in EH-WSNs has considered them to be ideal or over-simplified, with non-ideal behavior attributed to substantial leakage currents. In this brief, we show that observations previously attributed to leakage are predominantly due to redistribution of charge inside the supercapacitor. We confirm this hypothesis through the development of a circuit-based model which accurately represents non-ideal behavior. The model correlates well with practical validations representing the operation of an EH-WSN, and allows behavior to be simulated over long periods..
The second paper, 'Photovoltaic Sample-and-Hold Circuit Enabling MPPT Indoors for Low-Power Systems' presents an ultra low-power maximum power point tracking (MPPT) circuit with a novel sample-and-hold and cold-start arrangement, enabling efficient indoor MPPT (which has not been reported, or considered possible, before). The circuit is validated in practice, and the sample-and-hold behaviour analysed using real light data.
For more information, click here.
First DejaView PCBs3rd June 2010
Today we received the PCBs for the DejaView device (version 1)! Nearly a year has passed since we first began to think about how technology can better assist sufferes of memory loss, and we are well on the way to having our first new devices.
The device, forming a part of the dejaview system architecture (alongside a mobile-phone and web service) includes a three megapixel camera, bluetooth radio module, ARM Cortex-M3 microcontroller and an array of different sensors.
WiSE Project Day12th November 2008
WiSE held it's first 'Project Day', an intensive one-day problem-based exercise for PhD students in ECS that are researching wireless sensing related topics. Ten students took part in an intensive day which ran from 8am to 7pm! Two teams were formed, one of which was tasked with developing a piece of clinical equipment (in response to a request from a Surgeon at the local University Hospital), while the other was required to develop a sensor network to monitor our building.
The exercise prom... [more]