Improved pen harvester for powering a pulse rate sensor

Anthony Marin, Patrick Heitzmann, Jens Twiefel, Shashank Priya

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


With the continued advancement in electronics the power requirement for micro-sensors has been decreasing opening the possibility for incorporating on-board energy harvesting devices to create self-powered sensors. The requirement for the energy harvesters are small size, light weight and the possibility of a low-budget mass production. In this study, we focus on developing an energy harvester for powering a pulse rate sensor. We propose to integrate an inductive energy harvester within a commonly available pen to harvest vibration energy from normal human motions like jogging and jumping. An existing prototype was reviewed which consists of a magnet wedged between two mechanical springs housed within a cylindrical shell. A single copper coil surrounds the cylindrical shell which harvests energy through Faraday's effect during magnet oscillation. This study reports a design change to the previous prototype providing a significant reduction in the device foot print without causing major losses in power generation. By breaking the single coil in the previous prototype into three separate coils an increase in power density was achieved. Several pulse rate sensors were evaluated to determine a target power requirement of 0.3 mW. To evaluate the prototype as a potential solution, the harvester was excited at various frequencies and accelerations typically produced through jogging and jumping motion. The improved prototype generated 0.043 mW at 0.56 g rms and 3 Hz; and 0.13 mW at 1.14 g rms at 5 Hz. The design change allowed reduction in total volume from 8.59 cm 3 to 1.31 cm 3 without significant losses in power generation.

Original languageEnglish (US)
Title of host publicationActive and Passive Smart Structures and Integrated Systems 2012
StatePublished - 2012
EventActive and Passive Smart Structures and Integrated Systems 2012 - San Diego, CA, United States
Duration: Mar 12 2012Mar 15 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherActive and Passive Smart Structures and Integrated Systems 2012
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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