project/stefan.raileanu (#983)

* added my documentation - dj controller

* changed rezo for arhitecture

* my kicad

* link to github and changed schematic kicad

* put schematics in index.md

* good size for kicad and changed name

* webp for kicad

* clean

---------

Co-authored-by: raylaj23 <raileanu@Rayla-J.localdomain>
Co-authored-by: Irina Bradu <72762129+irina-b-dev@users.noreply.github.com>

Author: 3 people

website/versioned_docs/version-acs_cc/project/2026/stefan.raileanu/images/architecture.svg

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+# DJ Controller
+
+A standalone two-deck DJ controller running on the STM32U5, written in Rust.
+
+:::info
+
+**Author**: Stefan Răileanu \
+**GitHub Project Link**: [link_to_github](https://github.com/UPB-PMRust-Students/acs-project-2026-raylaj23)
+
+:::
+
+## Description
+
+A fully standalone two-deck DJ controller built on the STM32U5 
+microcontroller, written in Rust using the Embassy async embedded framework.
+The board reads WAV audio files from an SD card and allows real-time mixing 
+between two decks.
+
+Each deck has its own jog wheel (a rotary encoder with a disc on top), three
+EQ knobs (bass, mid, high), a low and high-pass filter, a volume knob, and 
+dedicated buttons for Play/Pause, Cue, Loop, Sync, and Headphone Cue Select. 
+Two shared controls: a crossfader and a headphone volume knob. Each deck has 
+its own display showing track name, position, BPM and the loop, or the SD card
+file list when in browse mode.
+
+Audio leaves the STM32U5 through its **internal DAC**: the main mix goes out via a 3.5mm 
+AUX jack into a **Marshall Middleton** speaker (using its built-in 50W amplifier), and the 
+cued deck is routed through a **TPA6132 headphone amplifier** to the headphone output.
+
+## Motivation
+
+I'm a techno enthusiast and wanted a project that combines the technical
+skills I'm learning with a hobby I already love.
+
+## Architecture
+
+The system is organized around four main architectural components: an **Input
+Handler** that aggregates all user controls, an **Audio Engine** that 
+streams, processes, and mixes audio in real time, a **Display Driver** that 
+renders per-deck UI, and an **Output Stage** that splits the final audio into 
+a main mix and a separate cue channel.
+
+* **Input Handler** — reads rotary encoders via GPIO interrupts, 
+potentiometers via ADC + DMA, and buttons via GPIO. Maintains a per-deck 
+state machine that distinguishes jog-wheel pitch-bend (rotate only), 
+scrubbing (press + rotate), and mode switching (short press toggles between 
+play and browse).
+
+* **Audio Engine** — streams two WAV files from the SD card simultaneously over SPI 
++ DMA. Each deck runs an independent DSP chain (3-band EQ + LPF + HPF as biquad 
+filters), then pitch/seek/loop/sync logic adjusts the read pointer or sample rate, 
+and a final mixer applies per-deck volume and the crossfader before pushing samples 
+to the STM32U5's internal DAC.
+
+* **Display Driver** — receives playback state from the Audio Engine and UI 
+navigation events from the Input Handler. In play mode it renders track name, 
+position, BPM, and loop/sync state. In browse mode it renders a scrollable list of 
+WAV files from the SD card.
+
+* **Output Stage** — the STM32U5's internal DAC produces two analog channels: the main
+mix is sent over a 3.5mm AUX jack into a Marshall Middleton speaker (which has its own
+built-in 50W amplifier), and the cue channel is sent through a TPA6132 headphone
+amplifier to the headphones (used by the DJ to prepare the next transition).
+
+![Architecture](images/architecture.svg)
+
+## Log
+
+### Week 21 - 27 April
+* Completed the documentation and ordered the hardware parts
+
+### Week 28 April - 4 May
+* Connected all the parts to stm
+
+### Week 5 - 11 May
+
+### Week 12 - 18 May
+
+### Week 19 - 25 May
+
+## Hardware
+
+The controller is built around the **STM32U5 Nucleo board**, which handles SD streaming, 
+DSP, display output, and input reading concurrently using Embassy's async runtime. Two WAV 
+streams are read from a microSD card over SPI with DMA so the CPU stays free for DSP. 
+Audio is generated by the **STM32U5's internal DAC** — no external DAC chip is used. The 
+main mix leaves the board through a **3.5mm AUX jack** and feeds a **Marshall Middleton** 
+speaker, which provides its own built-in 50W amplifier. The cue channel goes through a 
+**TPA6132 headphone amplifier** to the headphones (carrying only the cued deck).
+
+Each deck has a rotary encoder with a 3D-printed disc as a jog wheel, six potentiometers 
+(Bass / Mid / High EQ, LPF, HPF, Volume), and five push buttons (Play/Pause, Cue, Loop, 
+Sync, Headphone Cue Select). Shared controls are a crossfader and a headphone volume knob. 
+Two **ILI9341 2.4" TFT displays** (one per deck) connect over SPI and show playback state 
+in play mode and the file list in browse mode.
+
+### Schematics
+
+![Schematics](images/dj_controller.webp)
+
+### Bill of Materials
+
+| Device | Usage | Price |
+|--------|--------|-------|
+| [STM32U5 Nucleo Board](https://www.st.com/en/evaluation-tools/nucleo-u575zi-q.html) | Main microcontroller | — |
+| [TDA1308 Headphone Amplifier](https://www.emag.ro/amplificator-audio-stereo-pentru-casti-cu-tda1308-dc-3-6v-emg232/pd/DPSG9VYBM/?ref=fav_pd-title) | Headphone output | 24 RON |
+| [3.5mm Stereo Audio Jack (female) x2](https://ardushop.ro/en/electronics/2021-cjmcu-trrs-35mm-stereo-jack-module-6427854030856.html) | AUX output to speaker/headphone | 1.97 RON |
+| Marshall Middleton | Main speaker output via built-in 50W amplifier (AUX in) | — |
+| [Rotary Encoders ×2](https://ardushop.ro/en/electronics/1271-encoder-module-6427854018274.html) | Jog wheels — pitch-bend, scrubbing, browse | 10 RON |
+| [Potentiometers 10kΩ ×11](https://ardushop.ro/en/discrete-components/280-374-liniar-potentiometer-10k-50k-100k-6427854002952.html#/156-valoare_rezistenta-10k) | EQ Bass/Mid/High ×6, LPF ×2, HPF ×2, Headphone Vol ×1 | 1.31 x11 RON |
+| [Linear potentiometers x3](https://www.optimusdigital.ro/ro/componente-electronice-potentiometre/2420-modul-poteniometru-liniar.html)| Volume x 2, Crossfader x1 | 20 x3 RON|
+| [Push Buttons (×10)](https://ardushop.ro/en/buttons--switches/713-push-button-small-trough-hole-6427854009050.html) | Play/Pause ×2, Cue ×2, Loop ×2, Sync ×2, Headphone Cue Select ×2| 0.83 x10 RON |
+| [ILI9341 2.4" TFT Display (x2)](https://ardushop.ro/en/displays-and-leds/2534-lcd-tft-display-240x320-24-inch-il9341-touch-sd-6427854038630.html) | Per-deck display: track info, BPM, position, file list and SD module | 67 RON |
+| Micro sd card | storing the music | 40 RON |
+| [resistors](https://ardushop.ro/en/discrete-components/1444-set-rezistente-1-4w-600buc-30-valori-10r-1m-6427854021199.html), [capacitors](https://ardushop.ro/en/discrete-components/1299-set-electrolytic-capacitors-120pcs-12-values-022uf-470uf-6427854018779.html), [wires](https://ardushop.ro/en/wires-and-connectors/5-10-x-dupont-cables-male-male-10cm-6427854025869.html), [breadboard](https://ardushop.ro/en/electronics/2297-breadboard-830-points-mb-102-6427854012265.html), [leds](https://ardushop.ro/en/leds/293-468-5mm-led.html#/172-color-orange) | Debouncing, decoupling, wiring | 92 RON |
+| | | Total: 330 RON | 
+
+## Software
+
+| Library | Description | Usage |
+|---------|-------------|-------|
+| [embassy-rs](https://github.com/embassy-rs/embassy) | Async embedded framework for Rust | Main async runtime on STM32U5; drives SPI, internal DAC, ADC, and DMA peripherals concurrently |
+| [embedded-sdmmc](https://github.com/rust-embedded-community/embedded-sdmmc-rs) | SD card FAT filesystem driver | Reads WAV and `.cue` metadata files from the SD card |
+| [ili9341](https://crates.io/crates/ili9341) | ILI9341 TFT display driver | Drives the two per-deck displays over SPI |
+| [embedded-graphics](https://github.com/embedded-graphics/embedded-graphics) | 2D graphics library | Renders track info, BPM, loop/sync state, and the browse-mode file list |
+| [micromath](https://github.com/tarcieri/micromath) | Lightweight math for embedded | Biquad filter coefficient calculations for EQ, LPF, and HPF |
+
+## Links
+
+1. [STM32U5 Reference Manual](https://www.st.com/resource/en/reference_manual/rm0456-stm32u5-series-armbased-32bit-mcus-stmicroelectronics.pdf)
+2. [Embassy — Async Embedded Rust](https://embassy.dev/)
+3. [Numark Mixtrack Platinum FX — reference DJ controller](https://www.numark.com/product/mixtrack-platinum-fx)
+4. [WAV file format specification](http://soundfile.sapp.org/doc/WaveFormat/)
+5. [Cookbook formulae for audio EQ biquad filter coefficients (Robert Bristow-Johnson)](https://www.w3.org/TR/audio-eq-cookbook/)