CoyoPedal is a do‑it‑yourself guitar amp and effects pedal built around the Waveshare ESP32‑S3‑Touch‑AMOLED‑2.06 development board. That board provides a 410×502 pixel AMOLED touchscreen, 8 MB of PSRAM, a microSD card slot, and a USB port that the ESP32‑S3 can operate as a host for USB Audio Class 2 interfaces. The firmware, constructed with the Gea Stack, compiles a TypeScript‑based user interface to native C++ so no JavaScript engine runs on the device.
This image shows the physical hardware described in the article, including the ESP32‑S3 touchscreen board used for the pedal’s user interface and storage.
At its core CoyoPedal runs a full‑size Neural Amp Modeler (NAM) A2 WaveNet—a 23‑layer, eight‑channel model that processes audio at 48 kHz using block‑floating‑point arithmetic and hand‑written Xtensa kernels split across the ESP32‑S3’s two cores. Around this amp model the pedal places a configurable effects chain: a noise gate, compressor, chorus, and drive stage before the amp, followed by digital delay and stereo spring reverb after it. Users can tap each block on the touchscreen to toggle it on or off, hold to edit parameters via sliders, and manage presets that store amp, cabinet, and effect settings; an on‑screen keyboard lets them name presets, and a built‑in tuner mutes the output while active. The pedal also reads .nam or .namb capture files from a FAT‑formatted microSD card, creating a cached .s3cache file on first load for faster subsequent recalls, and supports user‑supplied impulse‑response files for cabinet simulation.
Because the same firmware is also built to WebAssembly, anyone can try the pedal in a browser at coyopedal.playtaurus.com, where the page acts as a virtual SD‑card folder for loading .nam files and mirrors any preset changes back to the local folder in Chrome or Edge. Performance measurements on a headless ESP32‑S3‑DevKitC show the A2 model consuming roughly 91‑94 % of the 1 333 µs per‑block budget across both cores, demonstrating that the full neural network can run in real time on the hardware without missed deadlines.