Imec and Holst Centre announce that they have made a micromachined harvester for vibration energy with a record output power of 489 µW. Measurements and simulation show that the harvester is also suited for shock-induced energy harvesting in car tires, where it could power built-in sensors. In a tire, at 45 mph, the new device can deliver a constant 42 µW, which is enough to power a simple wireless sensor node. These results, obtained within the research centre’s program for Micropower Generation and Storage, are presented at the 2011 IEEE International Electron Devices Meeting (IEDM) in Washington (December 7-9).
Imec’s innovative harvester consists of a cantilever with a piezoelectric layer sandwiched between metallic electrodes, forming a capacitor. At the tip of the cantilever a mass is attached, which translates the macroscopic vibration into a vertical movement – putting strain on the piezoelectric layer and generating a voltage across the capacitor. As piezoelectric material, AlN (aluminum nitride) was chosen. The harvesters are packaged with a 6-inch wafer scale vacuum packaging process. The micromachining production process is compatible with low-cost mass-production fabrication. [via]
Car tires harvest energy - [Link]
Stephen Evanczuk writes:
Micro-harvesting, or energy scavenging, relies on extracting power from minute but pervasive sources of ambient energy such as light, heat, RF, or vibration. With piezoelectric devices, energy from vibration can supply low-power applications, such as wireless sensors that are difficult to reach and maintain, for equipment or structural monitoring. By following a few key design considerations, engineers can build applications powered by piezoelectric transducers from Parallax, Measurement Specialties/Schaevitz, and Mide Technology and power management devices from Linear Technology.
Compared to other micro-harvesting energy sources, vibration and motion are relatively robust sources of ambient power (Figure 1). Placed on motors, for example, vibration-powered sensors can harvest power precisely when it is needed during motor operation. In a practical application, the piezoelectric transducer would likely be used to charge a high efficiency storage device rather than provide power directly to application circuits.
Energy Scavenging with Piezoelectric Transducers - [Link]
The same piezoelectric effect that ignites your gas grill with the push of a button could one day power sensors in your body via the respiration in your nose.
Writing in the September issue of the journal Energy and Environmental Science, Materials Science and Engineering Assistant Professor Xudong Wang, postdoctoral Researcher Chengliang Sun and graduate student Jian Shi report creating a plastic microbelt that vibrates when passed by low-speed airflow such as human respiration.
In certain materials, such as the polyvinylidene fluoride (PVDF) used by Wang’s team, an electric charge accumulates in response to applied mechanical stress. This is known as the piezoelectric effect. The researchers engineered PVDF to generate sufficient electrical energy from respiration to operate small electronic devices. [via]
Electricity from the nose - [Link]
Dave shows how the piezoelectric effect applies to oscilloscope probes. [via]
Oscilloscope Probe Noise when Physically Shocked – [Link]
Piezoelectric materials are about as close to magic as you can get. They turn physical pressure into electricity and can even turn electricity into physical pressure – an amazing sort of bidirectional converter for mechanical and electrical energies. Perhaps even more amazing is the fact that you can easily ‘grow’ your own piezoelectric crystals overnight using just a couple of common ingredients – awesome.
Collin’s Lab: Homebrew Piezo - [Link]
I-Swarm robot is a fully-integrated and functional micro robot. What makes these robots so impressive is the level of integration; they possess a micro-step locomotion mechanism, a solar cell, custom IR communication modules, and an ASIC (custom silicon circuitry) all in a very compact package.
The locomotion unit consists of a flexible printed circuit board (FPC) with three legs that have a piezoelectric polymer actuator multilayer film on top.
I-Swarm Micro Robots Realized – [Link]