![[piezo animation]](/julius-gun/piezopendulum/blob/main/assets/piezopendulum_animation.gif)
This project revitalizes a classic 1993 piezoelectric pendulum, a key educational tool at the Technical University of Munich. The original, while brilliant, was facing obsolescence due to aging electronics and inaccessible Assembler software. The vision was to engineer a modern, robust, and user-friendly successor that preserves its core teaching value for the next generation of engineers.
The new demonstrator successfully replicates all key operations of the original, including self-sensing impulse detection, launching a suspended ball, and achieving a precise, bounce-free catch upon its return.
- Complete Technological Overhaul: Replaced 30-year-old electronics and Assembler code with a modern system based on a Raspberry Pi Pico and C++.
- Self-Sensing Actuation: The piezo actuator itself detects the returning ball's impact, eliminating the need for external sensors.
- Precise Bounce-Free Catch: The system discharges the piezo's energy at the right moment, causing the ball to "stick" to the actuator without bouncing.
- Integrated & Robust Design: A compact, 3D-printed enclosure integrates the actuator and control unit, eliminating fragile external cables.
- Intuitive User Interface: Simple rotary encoder and a clear LCD screen.
The project followed a clear modernization path:
- Electronics Redesign: A custom PCB was designed featuring a half-bridge configuration with fast-switching MOSFETs and a bootstrap gate driver to precisely control the high-voltage piezo actuator.
- Intelligent Control: A Raspberry Pi Pico runs the C++ firmware, handling user input, display updates, and the critical microsecond-level timing required for the bounce-free catch.
- Physical Redesign: The enclosure and actuator mount were designed in CAD and 3D printed, allowing for rapid prototyping and a compact, integrated final form.
For a complete technical deep-dive, including schematics, code, and design evaluation, you can access the full bachelor's thesis.