Progress 05/15/04 to 12/31/04
Outputs
This Small Business Innovation Research Phase I project demonstrated the feasibility of using animal motion to generate power for animal telemetry devices. The Phase I research focused on avian species to prove the feasibility of a non-invasive means of generating sufficient electrical power from host bird's motion that can be integrated with TenXsys' already developed animal telemetry devices. The Phase I work used homing pigeons and captive wood ducks to gather motion data that was then used in simulations to determine the amount of mechanical energy available for a scavenging device. Developing an instrument that was light-weight and capable of sampling 3 axes of acceleration at 60 Hz, with at least 8 hours of storage space, was challenging and required the use of TenXsys R&D funds. The total weight of the first version electronics, battery, packaging, and harness material was 18.8 grams. Our aspirational goal for total weight was 9 grams, and the maximum allowable
weight was 15 grams (3% of the host bird's body weight). Since our initial assembly exceeded the weight limit, we redesigned the electronics, case, and attachment means. A different battery was selected, a 1/3N, 3V, 320 mAH, weight 3.6 gm, for a weight savings of 5.8 grams. The base, used to attach the electronics to the bird, was simplified to be a strip of Velcro punched with slots for threading the Teflon ribbon. The case was reduced to a length of heat shrinkable tubing, with a strip of adhesive backed Velcro that attached to the base Velcro. The total weight of version 2 electronics, battery, base, case, and harness material is 10.8 grams, within our allowable range. The model used in the design study was a simple, second order, spring-mass model with linear energy conversion equations. The charging circuit is modeled as a pure resistive load. The oscillator was modeled in Simulink based on a transfer function. The input of the model was a Matlab vector containing the actual time
record of the z-axis acceleration from the homing pigeon studies. The power (rate of energy converted) output of this model was given by the voltage of the generator circuit and the current delivered to the load. This quantity is specific power as it indicates the amount of power generated per unit mass of the proof mass. The Simulink scaling factor for mass in the computation was set at 1 gram. All results used a 1 gram proof mass, but they scale directly. Using a script file in Matlab, the simulation was run for a wide range of input parameter values. Knowing that the input signal contained a dominant frequency component around 7.5 Hz, the parameter values were chosen to bracket that value. In addition, a range of parameter values were chosen so that we could see its effect on the energy generated. The simulation showed a range of available energy from 2mJ up to 11 mJ of total energy. This is sufficient energy to trickle charge a small rechargeable battery, thus proving the
feasibility of our energy-scavenging animal telemetry device for avian species.
Impacts
This technology will allow scientists and researchers to track animals in remote regions and watch large scale movements as never before. Ecological studies will provide the insight to the trends of natural history, and will enable humans to coexist peacefully with all species of animals. Through the research that the expanded wildlife studies will perform, our natural resources and environment can be better understood and protected, and more informed land management decisions made. The ambient power device developed will be integrated into various small electronic devices such as animal telemetry devices and other devices that are regularly moved about such as cell phones, PDAs, hearing aids, pedometers, or pace makers. These devices will allow motion and acceleration to be converted electrical power to recharge batteries for longer-term device operation without user intervention, or to reduce the dependence on batteries altogether. Our kinetic energy scavenger will
be very attractive to both the battery manufacturers and the consumer device manufacturers. As per business impact, a successful kinetic energy scavenger offers significant competitive advantages by being lighter weight, enabling longer-duration studies, allowing more sensors instead of batteries, and being maintenance-free relative to battery or solar powered animal telemetry devices. In the consumer products market, our kinetic energy scavenger will provide cell phones, PDAs, and laptops a means of recharging their batteries as the devices are being moved about, thus providing longer on the go operation.
Publications
- No publications reported this period
|