Description: This breakout board uses the LTC3588 Piezoelectric Energy Harvester from Linear Technologies. This board can be used not only for harvesting piezoelectric energy, but solar energy as well. There is a bridge rectified input for piezo elements (PZ1 and PZ2) and a direct input (VIN) for DC sources. Both are clamped to 20V. In addition, the board can simply be used as a standalone nanopower buck regulator.
An ultralow quiescent current undervoltage lockout (UVLO) mode with a wide hysteresis window allows charge to accumulate on an input capacitor until the buck converter can efficiently transfer a portion of the stored charge to the output. In regulation, the LTC3588 enters a sleep state in which both input and output quiescent currents are minimal. The buck converter turns on and off as needed to maintain regulation.
Four output voltages (1.8V, 2.5V, 3.3V and 3.6V) are pin selectable with up to 100mA of continuous output current and comes pre-configured for an output of 3.3V. However, the output capacitor may be sized to service a higher output current burst. An input protective shunt set at 20V enables greater energy storage for a given amount of input capacitance.
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I’ve burnt through two of these boards with the exact circuit shown in the video. My theory (tested with an Oscope) is sometimes the piezo spikes above 20 V and burns out an internal component. You’d think there’d be protection built in…
On the flip side, I’ve found that hooking up the piezo to a voltage rectifier using a few diodes, and then a capacitor provides a good, low cost solution.
To change the output of the energy harvester you would need to move the solder jumper for either D1 or D0. Default is set to Vout = 3.3V:
(D1, D0) – VOUT (0, 0) – 1.8V (0, 1) – 2.5V (1, 0) – 3.3V (1, 1) – 3.6V
For more information, look at page 9 of the datasheet LTC3588 http://cds.linear.com/docs/en/datasheet/35881fb.pdf.
Testing it with the smaller piezo element [ https://www.sparkfun.com/products/10293 ] in our storefront, it does work but you have to bang it on the edge of the table with a pen so there is enough vibration to generate power for the harvester. It’s not efficient but it will work… eventually. You can see some small sparks on the piezo in the dark. It will probably be damaged by the time you generate enough energy.
Looking at the piezo using a oscilloscope, the MIDEV21BL had more vibrations and spikes than the piezo element. The piezos from MEAS loaded with masses had a significantly smaller spike than the other components.
A MIDE V21BL energy harvesting piezo (retired) was used in the demo video => http://www.mide.com/products/volture/piezoelectric-vibration-energy-harvesters.php. The parts used include:
Try looking at this schematic to hook it up => https://drive.google.com/open?id=0B0jwgLkjMWzDdnFCWW4yc3RGM0E&authuser=0.
Here’s an image of the application circuit wired up from the demo video => https://drive.google.com/open?id=0B0jwgLkjMWzDeFNuendDb0JCMWs&authuser=0.
For a quick test to see if it is working. The engineer that designed the breakout board suggested that you should try putting 5V through the Vin pin and see if you get 3.6V at the VCC side. If you are getting 3.6V at the Vcc pin, it verifies that the board is working.
I tried 3.3V and 5V but the energy harvester was not able to output any voltage at VIN. I then tried using 8V from my power supply set to 30mA and I was able to see an output of 3.3V based on the settings that my board was set to.