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FIG. 02 — ENERGY CONVERSION

The Science Behind Every Step

Six stages take a footstep and convert the mechanical work into electrical power.

SIGNAL FLOW

From pressure to charging potential

  1. 01

    Mechanical Pressure

    A footstep presses down on the top plate and squeezes the discs underneath.

  2. 02

    Piezoelectric Response

    The PZT ceramic inside each disc deforms slightly, which shifts electric charges and creates a voltage.

  3. 03

    Electrical Output

    Pressing and releasing makes the voltage swing back and forth, so the raw output is alternating current (AC).

  4. 04

    Rectification

    A bridge rectifier of four diodes flips the negative swings so current only flows in one direction (DC).

  5. 05

    Storage

    A capacitor collects the small pulses from many presses and holds the charge.

  6. 06

    CHARGING DEMONSTRATION

    When enough charge builds up, the capacitor releases it into an powerbank module that charges a battery and stores energy, which is then used to charge a device using a USB-A cable.

Did you know?

Piezo discs output AC, not DC — the voltage flips direction between pressing and releasing. That's why the bridge rectifier exists: a capacitor and powerbank module need current flowing one way.

FIG. 03 — HARDWARE

Components

Every component and the role it plays in the circuit. Building blocks that turn ideas into working prototypes for real life application.

C-01

PZT Piezoelectric Discs

Function: Generate a small voltage when pressed.

Role: The energy source — 10–20 discs form the sensing array.

C-02

Acrylic Plates

Function: Sandwich the discs and spread the force of a step.

Role: Mechanical structure and even pressure distribution.

C-03

Parallel Wiring

Function: Connects the discs so their outputs combine.

Role: Lets current from many discs add together.

C-04

Bridge Rectifier

Function: Converts the AC output of the discs to DC.

Role: Makes the signal usable for storage.

C-05

Capacitor

Function: Stores charge collected over many presses.

Role: Energy buffer between harvesting and use.

C-06

Wires

Function: Carry current between every stage.

Role: Physical links in the electrical pathway.

C-07

Multimeter

Function: Measures voltage across the circuit.

Role: Used to observe output during testing.

C-08

Power Bank Module

Function: Charges a device over a USB-A cable using stored energy.

Role: Turns stored charge in the battery into usable charging output.

BUILD LOG

From Components to a Working Prototype

  1. Step 1

    Design

    I sketched the disc layout and plate structure; including the orientation of the piezoelectric transducers.

  2. Step 2

    Assembly

    Discs were fixed between the acrylic plates which a firm yet compressable material to transfer the pressure to the discs on either sides of the plate.

  3. Step 3

    Electrical Connections

    The discs were wired together in parallel using electrical wires that were soldered carefully to ensure the piezoelectric function is not lost.

  4. Step 4

    Circuit Integration

    The bridge rectifier and capacitor were added that convert the Alternating current to Direct current and store the charge respectively.

  5. Step 5

    Testing

    Output was observed with a multimeter under the 20V setting to identify the voltage that is being produced and how it will be transferred.

  6. Step 6

    Demonstration

    Stored energy was used to charge a device using a power bank module which applies the final touch to the entire idea.

FIG. 04 — CIRCUIT PATH

Following the Electrical Pathway

Piezo Array

Pressure creates AC voltage that is passed to the bridge rectifier.

Bridge Rectifier

AC becomes DC the the use to diodes connected in a Full-Wave Bridge rectification design.

CAPACITOR & BATTERY

DC charge is stored in capacitor to be transferred at a constant rate to the battery.

POWER BANK FUNCTION

Stored energy charges devices via the Power Bank module.