IEBPROJECT CASE STUDY
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A large science fair poster titled Pielar Panel with columns of research text, cost tables, an efficiency comparison table and photographs, set over a photo of rain on a solar panel

Science-fair prototypeDrawing 20 of 47

Pielar
Panel

A solar panel sitting on springs above a bed of eighteen piezoelectric discs, so rain hitting the panel makes power too. A classmate and I built it for a science fair in March 2019.

Sheet 02 of 07/The idea

The idea

Our idea was to put a solar panel on springs over a bed of piezoelectric discs, so rain would push the panel down and make power on its own.

A CAD render of three flat teal panels stacked in an exploded view, the top one covered in a grid of small circular seats
PL 02The three printed parts: the solar panel carrier on springs, the bed with eighteen seats for the piezoelectric discs, and the circuit tray with its cap.

Sheet 03 of 07/The build

What we built

We 3D printed three stacked parts: a carrier on six springs, a bed of eighteen piezoelectric discs, and a circuit tray with a switch and an LED that lights up to show the charge coming back out.

A hand drawn wiring diagram showing eighteen piezoelectric discs in three columns wired down to five capacitors, a resistor, a switch and an LED
PL 03The eighteen discs are wired in three strings into a capacitor bank, a 100 ohm resistor, a tactile switch and one LED, so you can dump the stored charge and see it.

Sheet 04 of 07/The crystal

Trying to grow a crystal

We tried to grow our own piezoelectric material, Rochelle salt. We cooked it on the stove and left it for a month, but nothing crystallized because we used baking soda instead of washing soda.

A photograph of a flexible dark solar panel next to a small circuit board wrapped in yellow tape
PL 04The thin film solar panel and the first circuit, taped up on a workbench before it went into the printed frame.

Sheet 05 of 07/The numbers

Where the numbers come from

The numbers on the board come from a spreadsheet, and none of them were measured. We calculated an 18 to 107 percent improvement from 30-year rain and sun averages, and the board's own results claim a lot more than that.

Two data tables comparing average monthly rainfall, sunshine hours, water drops per square inch and joules produced for Austin and Philadelphia
PL 05Our results all come from this spreadsheet. It uses rainfall and sunshine averages for Austin and Philadelphia and 0.3 joules per drop to work out the improvement.
Eight photographs of a glass measuring jug in a saucepan of simmering water, being stirred, and clear plastic containers of solution left to crystallise

Sheet 06 of 07/Next time

What I'd do differently

Next time I'd measure a real panel against a bare one before doing any more math. We calculated a lot but never tested the real thing.

PL 06Trying to grow our own Rochelle salt in a double boiler on the kitchen stove. A month later there was still nothing in the containers.

Sheet 07 of 07/Source

Inspect the work