Volture - Frequently Asked Questions

Q1. What are it's vibration energy scavenging advantages?
The Volture is a robust, reliable and inexpensive means to harvest vibration energy for you application! The Volture vibration energy harvester device harvests otherwise wasted energy from mechanical vibrations. The Volture accomplishes this by using piezoelectric materials to convert mechanical strain into useable electrical energy. The Midé Volture energy harvester is unique because it incorporates Midé's patented QuickPack Piezoelectric transducer technology. Through a proprietary manufacturing process, the QuickPack transducer packages piezoelectric materials in a protective skin with pre-attached electrical leads, producing a highly reliable component with no soldered wires. The QuickPack actuator's protective skin also provides electrical insulation and defense against humidity and harsh contaminants.

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Q2. What is a Raw Volture Vibration Energy Harvester?
Mide currently offers six energy harvesting products. Both the PEH20W and PEH25W include power conditioning electronics as well as an anodized enclosure with integrated clamp. When you order a raw energy harvester, the V20W, V25W, V21B, or V21BL, you will just receive the packaged piezo energy harvester with pre-routed mounting holes and connector. You will NOT receive the power conditioning electronics or anodized case with integrated clamp. This product is good for "testing" the technology and seeing how it will fit into your application.

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Q3. What are Energy Harvesting Electronics?
The output from a cantilevered piezo element in the presence of a vibration is sinusoidal or AC (alternating current). Most sensors that would be powered by an energy harvester require DC (direct current) power. Thus the raw AC output from the piezo needs to be converted from AC to DC. This process is done using a simple rectifying circuit. Midé currently offers two forms of its power conditioning electronics, the ehe001c has a capacitive storage element, and the other, the ehe001nc, has no capacitive storage element. More sophisticated electronics are available for directly powering sensors and charging specific batteries. Please contact Chris Ludlow (through our contact page) if you would like to learn more.

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Q4. What is the unit cost at high volume?
Mide has performed extensive quotes for high volume production with results in the $1  to $10 dollar range.  The discrepancy is due to the size of the device.  A smaller device with a small amount of materials will be cheaper than a larger product.

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Q5. How much power will I get out?
This depends on a number of factors.  The first factor is which product you are using.  The second factor is what is your vibration environment?  The last factor is how well is your device tuned to the vibration frequency.  On the product pages there is a performance tab at the top of the page that gives the performance envelope for the current product offerings.

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Q6. What is the energy harvesting bandwidth?
The Volture is a cantilevered beam with a natural frequency that is matched to the vibrating structure.  If the vibration changes slightly the power from the Volture goes down.  The energy harvesting bandwidth is the frequency range around the tuned frequency where 50% of the peak power is still available from the Volture.

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Q7. Can Mide make different shapes and sizes?
Yes, our manufacturing facility gives us the opportunity to make virtually any shape or size you wish.  If you require a custom shape or size please contact Mide.

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Q8. How robust is the Volture?
Compared to bare piezo wafers, the Volture is very robust.  There are limits however to how hard the device can be driven.  Being a cantilevered beam (often with a tip mass) the device is designed to strain and thus produce power.  However if the piezo material is over strained it will either slowly fail via fatigue or catastrophically fail.  For design purposes (with a built in factor of safety) Mide keeps the maximum strain witnessed by the piezo below 800 us.

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Q9. What is your lead time?
We keep a small number of products on the shelf, so usually our lead time is less than a week.  However if parts need to be manufactured our lead time will be 2-3 weeks.

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Q10. How fast can you make a million for me!?
We currently produce over 20,000 products a year.  Our current manufacturing line has the capability to produce over a million units a year.  We would be able to ramp to production of one million units in 6-12 months.

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Q11. How do I mount the Volture?
This depends on which product you need to mount.  The PEH systems come with four mounting holes that can be used to attach to your vibration structure.  It is also acceptable to adhere or tape the system to the structure.  The raw Volture requires a bit more work.  A clamp needs to be made to attach the Volture in a cantilevered manner.

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Q12. Can I get power from someone walking?
Yes…..but not much.  Typically the Volture is best used at higher frequencies than a person walking generates.  That said, Mide has generated acceptable power levels from “impact” situations where the Volture is excited by an impact (stomping of foot) and the device rings out to give power.  However there tends to be a lot of damping on a human body (some more than others) that diminishes the power output.

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Q13. How do I tune my raw Volture?
After the device is clamped properly, add a tip mass to the end of the device.  Drive the device at the desired vibration and monitor the output of the Volture.  Re-position the mass until the maximum power (voltage) level is found.  Your device is now tuned.  Best ways to adhere the tip mass are bee’s wax during tuning and then super glue or a high quality adhesive once the tuned position is found.

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Q14. I’m not getting anything out of my Volture, what is wrong?
Most likely you are not driving the Volture at a frequency near the natural frequency of the Volture.  However it is possible that your device is not operating properly.  To check this, take the device in your hand and lightly tap the device on your knuckle.  Monitor the output using an oscilloscope to see the voltage output.  If you see nothing, ensure that the scope is set to a low voltage division and that the probe multiplication is appropriate.  If you still see nothing out, contact Mide.

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Q15. How do I Tune my Volture Energy Harvester??
The simplest and easiest means to tune the Volture is to use a proof mass or tungsten tuning mass. A tip mass has the effect of driving down the natural frequency of the Volture™. Midé offers for sale thin tungsten tip masses that are machined to fit in an ultra low profile onto Midé’s Volture™ products. The products are made from tungsten to ensure the most possible mass in the smallest volume. The mass can be attached to the Volture™ harvesters using adhesive for permanent installations, or bee’s wax for prototype installations. Obtaining authority over the natural frequency of the Volture™ for a given tip mass can be achieved by translating the tungsten tip mass along the length of the Volture™ until the appropriate tuning is reached.

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For more information:

Please contact Chris Ludlow (Products), or call: 781-306-0609 x227