sangibeaud / blackstomp

ESP32-A1S Digital Audio Effect Processor

BLACKSTOMP

• Description: A quick development platform for ESP32-A1S digital effect pedal
• Version: 3.7

Features

• Dual core 240MHz Tensilica Xtensa LX-6 (32-bit processor with floating point unit)
• WiFi and Bluetooth connectivity
• 24-bit stereo codec with analog pass-through bypass
• Six control inputs (for potentiometers, expression pedal, button, or selector switch)
• 3 buttons inputs (for foot switches)
• Guitar input
• Microphone input
• Stereo input/output
• MIDI input/output

Available Sketches Example

• Taptempo Stereo (Ping-Pong) Delay
• Stereo Chorus
• BLE Pedal
• MIDI Pedal
• Mic Mixer
• Gain Doubler
• Distortion

TODO List

• Provide BLE terminal client app and implement debug monitoring API via BLE, so the Serial port can be dedicated for MIDI
• Provide implementation of multi-button mode of the control input

Change History

• Version 3.7
  • Edited bsdsp.h, bsdsp.cpp, and distortion.ino for more consistent camelCase class naming
  • Changed level detection algo in noiseGate object using only fullwave rectifier and 4th order 20Hz low pass filter
  • Added distortion.ino in the example (stacked distortion with tone control and noise gate)
• Version 3.6
  • Added waveshaper, rchipass, rclopass, simpletone, and noisegate objects in the library (bsdsp.h, bsdsp.cpp)
  • Added distortion.ino in the example (stacked distortion with tone control and noise gate)
• Version 3.5
  • Changed buffer count from 20 to 2 for 2 ms measured latency
  • Added BGPM-2 schematic and PCB gerber file
• Version 3.4
  • Added tap multiplier control and re-arrange the previous controls in taptempodelay scketch
  • Added noise gate control in micmixer sketch example
  • Added conversion optimization control in gaindoubler sketch example
  • Fixed optimizeConversion function to be callable inside setup
  • Added commented (inactive) optimizeConversion() code inside setup() section of all example sketches
• Version 3.3
  • Added optimizeConversion(range) API for ES8388-version module to produce much less noise at default range 250mVrms/707mVpp
  • Enabled ALC to reduce the clipping effect for limited range of ES8388 version module
  • Enabled ALC to boost the microphoe gain with minimal compression and limiting effect
  • Added setMicNoiseGate() API to use the noise gate feature of ES8388-version module
  • Added setPhase method and setWaveTable method for oscillator object to accomodate non-sinusoidal waveforms
  • Added runScope function for sending real-time waveform data to Arduino IDE's serial plotter
• Version 3.2
  • Added slowSpeed property in control object to suppress the internal noise of ES8388 version in CM_POT control mode
  • Fixed some error in example scketches
• Version 3.1
  • Fixed uninitialized button pins for ES8388 version module
• Version 3.0
  • Adding setDeviceType() function to support for both AC101 version and the new ES8388 version of the ESP32-A1S module
  • Removing setOutMix() API function
  • Adding new bypass mode parameter for analogBypass() and analogSoftBypass() API function
• Version 2.1 Edited Gain Doubler sketch example to synchronize with the manual document.
• Version 2.0
  • All sketches in the example now left the main loop empty to dedicate core 1 for audio processing task
  • Performance monitoring method runSystemMonitor has been added to the API, can be called after blackstompSetup when MIDI is not implemented
  • All task's priorities has been reverted back to the same priority with audioprocessing task, except for the performance monitoring task which is the lowest (idle) priority
• Version 1.3 Fatal error fix at blackstomp.cpp at line 555 and 565
• Version 1.2 Changing the example sketches: change the serial to 9600 baud, deactivate the system info printing by commenting the code lines inside the loop
• Version 1.1 Fixed blackstomp.cpp at line 555 and 565
• Version 1.0 Initial release

Documentation

• Blackstomp hardware and software programming manual at https://www.deeptronic.com/blackstomp/