Pi looper

Project Introduction
One sentence “sound bite” that describes our
project.
“Pi-Looper”, an innovative and affordable loop station empowers musicians to record and create their
musical journey.
A summary of what we did and why.
A loop station is a music device used by musicians for recording, looping, and playing back audio
snippets in real-time during performance. It allows musicians to capture and reproduce short musical
segments, often played on instruments or vocals, and then layer these recordings on top of each other to
build complex arrangements.
We developed a loop station called “Pi-Looper” using Raspberry Pi Pico that empowers musicians to
effortlessly layer, record, and save instrument tracks. Unlike traditional loop stations, “Pi-Looper”
incorporates FRAM to enable users to save and retrieve tracks through serial communication, providing a
new level of flexibility and persistence in music creations. We designed and tested an amplifier circuit
to amplify instrument signal, in our case a guitar signal, to an optimal input range for the pico’s ADC.
We then implemented loop station logic by designing a finite state machine (FSM) based on button inputs
for record, playback, stop, and clear functionalities.

Detailed Project Description

Pi looper is an embedded-systems build that integrates sensors, actuators, a microcontroller and firmware into one working device, with the design decisions and test results documented so it can be reproduced.

How It Works
1. Input devices (sensors, buttons, encoders, wireless links) are connected to the microcontroller.
2. Firmware samples the inputs at a fixed rate and runs the control/processing logic (often with interrupts, timers or PIO for precise timing).
3. Outputs (motors, LEDs, displays, audio, radio) are driven according to the result.
4. The system is tested against its specification and tuned for reliability and responsiveness.

Key Components and Their Role
- Raspberry Pi Pico (RP2040): dual-core Cortex-M0+ microcontroller with PIO state machines used for precise, low-level timing.
- RP2040: dual-core Cortex-M0+ microcontroller with programmable I/O used for precise, low-level timing.
- Raspberry Pi: single-board Linux computer that runs the higher-level processing and networking.
- Bluetooth Low Energy: short-range low-power wireless link to a phone or browser.

Implementation Steps
1. Collect the components and study each module's datasheet (pin-out, voltage, interface).
2. Wire the circuit on a breadboard following the pin mapping; power sensors from the correct rail (3.3 V / 5 V).
3. Install C, Arduino IDE and the required libraries; flash a minimal test sketch for each module separately.
4. Write the main firmware: read sensors → process → drive outputs / send data.
5. Configure network or cloud credentials and test communication end-to-end.
6. Calibrate thresholds, add error handling (reconnect, sensor time-out) and run a long-duration test.
7. Finalise on a PCB / enclosure and document wiring, code and results.

Key Features
- Real-time firmware
- Custom hardware integration
- Measured performance
- Documented design and trade-offs

Expected Output
On completion the student will have a demonstrable device that meets its functional specification, with wiring diagram, code and results.

Deliverables
- Complete source code with comments
- Circuit diagram and pin mapping
- Project report with screenshots and results
- Demonstration-ready build