Piezoelectric Shoe Soles

Issues:

• Our planet faces an energy crisis due to climate change and pollution.

• Traditional energy sources contribute to greenhouse gases and are unsustainable.

• Kinetic energy from human movement is wasted every day.

• Sedentary lifestyles contribute to health problems like obesity and heart disease.

Our Solution:

• Integrates piezoelectric sensors into 3D-printed shoe soles to harvest energy.

• Converts mechanical energy from walking into electrical energy.

• Energy can be stored in batteries or capacitors to power devices like fitness trackers and smartphones.

• TPU-based 3D-printed housing ensures comfort and durability.

• Encourages sustainable energy generation and reduces reliance on fossil fuels.

1. 12 x 27mm Piezoelectric Discs
2. 4 x Schottky Diodes (1N5819) for a Bridge Rectifier
3. 5V Boost Converter (Power Supply Module Lithium Battery Li-ion Charging Protection Board 134N3P)
4. 18650 Battery Storage Case/Charging Board
5. 1￵8￵6￵5￵0 Rechargeable Battery
6. 3D-printed Sole pieces: 85A ninjaflex filament (More below)

1. Connect Piezo Discs in Series:
2. Take Piezo Disc #1 and connect its negative (-) lead to the positive (+) lead of Piezo Disc #2.
3. Repeat the wiring pattern on the rest Piezo Discs.
4. The remaining positive lead of Piezo Disc #1 and the negative lead of Piezo Disc #12 will be the final output.
5. Connect to a Bridge Rectifier:
6. Final Positive Lead (Piezo #1) → Connect to AC1 input of the bridge rectifier.
7. Final Negative Lead (Piezo #12) → Connect to AC2 input of the bridge rectifier.
8. Rectify AC to DC Using Schottky Diode Bridge:
9. Bridge Rectifier DC Output (+) → Connect to Boost Converter IN+.
10. Bridge Rectifier DC Output (-) → Connect to Boost Converter IN-.
11. Charge the Battery:
12. Boost Converter 5V OUT+ → Connect to Battery Charging Board IN+.
13. Boost Converter Ground → Connect to Battery Charging Board IN-.
14. Connect to 18650 Battery:
15. Battery Charging Board Output → Connect to Battery Holder + and -.

OPTION 1: DOWNLOADING THE STL

1. Download the STL file from below
2. Proceed to the printing section

OPTION 2: CAD THE SHOE SOLE

1. Make a drawing of your shoe sole, scan it, and then import the scan into Fusion 360.
2. Carve out a space for the piezoelectric sensors as well as the other electrical components.
3. Create a cover for the shoe sole that can be stepped on and has a loose tolerance
4. Cut the different parts according to the size restraints of your build plate and add connection segments.
5. Proceed to the printing

Slicing: We used curaLE as a slicer

Printing: We used a Lulzbot Mini (infill of the shoe sole is 15% with the "cross" pattern)

Filament: 85A ninjaflex

Dr. Rayne Zheng's research team at Virginia Tech is at the forefront of developing advanced 3D-printed piezoelectric materials. This technology achieves much higher levels of efficiency, and is a lot easier to manipulate and incorporate into custom designs. In the future, such materials could be used to capture wasted kinetic energy in new ways and possibly even power daily electric devices we use today.