Research Themes:

• Microfabricated electromagnetic power generator
• Vibration based power generator
• Inductive powering
• Electrochemical Micropower

There has been a growing interest in the field of miniature wireless sensors such as body worn health monitoring sensors and embedded sensors in automotive applications or buildings. Many applications require such sensors to be completely embedded in the structure or clothing with no physical connection to the outside world. As a result, they need to have their own power supply unit. Miniaturization possibilities are offered by using a thin film micro battery; however the device lifetime still depends on its energy storage capacity. Micro generators offer the solution to this problem, adding to microsystems the ability of recharging their energy storage by converting energy from the external environment to electrical power. Within the different forms of energy available, we focus on the mechanical vibrations and movements for the micro and batch fabrication of power generators.

Electromagnetic Power Generator, using Bulk magnets & Integrated coils

The images below show a micro-fabricated electromagnetic vibration generator developed under the VIBES project (http://www.vibes.ecs.soton.ac.uk) . The paddle and beam is fabricated using DRIE etching and a micro-coil is formed on the paddle using electrodeposition. Bulk magnets are placed in a separate Perspex chip holder above and below the coils. The paddle moves under the influence of external vibrations, thus moving the coil relative to the magnets and inducing a voltage in the coil.

Above: Images of a micro-fabricated vibration generator. Clockwise from top left, DRIE etched paddle and beam with micro-coil, close up of micro-coil, fully assembled generator, paddle and beam with top and bottom Perspex chips for holding the magnets.

Projects:

1. Vibrational Energy Harvesting (VIBES): funded under the EU FrameWork 6 programme. http://www.vibes.ecs.soton.ac.uk/
2. Wearable Generator Structures funded under by the Irish Higher Education Authority.

Contact:  Saibal Roy – saibal.roy@tyndall.ie | webpage

Selected Publications:

1. S P Beeby 1, R N Torah 1, M J Tudor 1, P Glynne-Jones 1, T O’Donnell 2, C R Saha 2 and S Roy 2 “ Micro electromagnetic generator for vibration energy harvesting” Journal of Micromechanics and Microengineering, 17 (2007) 1257-1265.
2. T. O’Donnell, C. Saha, S. Beeby and J. Tudor, “Scaling Effects for Electromagnetic Vibrational power Generator”, Microsystems Technology, Jan. 2007 http://dx.doi.org/10.1007/s00542-006-0363-0
3. S. P. Beeby , M. J. Tudor, R. N. Torah, S. Roberts , T. O’Donnell and S. Roy, “Experimental comparison of macro and micro scale electromagnetic vibration powered generators”, Microsystem Technologies, Jan. 2007, http://dx.doi.org/10.1007/s00542-006-0374-x
4. C.Saha, T.O’Donnell, S.Beeby, J. Tudor, “Optimisation of Electromagnetic Vibrational Energy Harvesting Device, IEEE Trans. Magnetics, 2006, vol. 42, no. 10, October 2006.
5. E. Koukharenko, S. P. Beeby, M. J. Tudor, N. M. White, T. O’Donnell, C.Saha, S. Kulkarni and S. Roy, "Microelectromechanical systems vibration powered electromagnetic generator for wireless sensor applications" Microsystems Technology, Volume 12, Numbers 10-11 / September, 2006, Pages 1071-1077
6. O. Chevalerais, T. O’Donnell, S. C. O’Mathuna, “Inductive Telemetry of Sensor Modules”, IEEE Pervasive Computing, vol 4. no. 1, Jan-Mar 2005, pp46-52..