To take full advantage of the ESP32’s features, I will set up a mobile phone interface that enables complete control over my multi-effect chain’s components via either WIFI or Bluetooth. The first notable solution for creating the app is the MIT App Inventor, a visual programming environment designed to build fully functional apps for Android and iOS smartphones or tablets.
A more complex option for my purposes is TouchOSC, a modular control surface toolkit used to design and construct custom controllers compatible with a wide range of operating systems and devices. TouchOSC can communicate with other software and hardware using the MIDI and Open Sound Control protocols in a variety of ways, also via different types of wired and wireless connections simultaneously.
The development of this remote control application will not only reduce the size of the physical interface on the device but will also expand its capabilities significantly. On the unit, the controls will include only the basic parameters, such as volume, rate, and mode, all controlled by rotary encoders and displayed on an LCD module.
In the app, however, the possibilities are greatly expandable, allowing for operations such as selecting which individual taps of the delay line will be scanned, setting presets, and changing the order of the components in the chain. Compared to the original Hammond unit that had a fixed rate and only 3 presets for both Vibrato and Chorus, this design will offer much more flexibility in shaping the width and rate of the phase shift that is applied to the audio signal.
Sources:
Appinventor.mit.edu. n.d. About Us. [online] Available at: <https://appinventor.mit.edu/about-us> [Accessed 27 December 2021].
Antonio, J., 2020. ESP32. WiFi. WebServer. LED on/off. Static IP. Soft Access Point. [online] MIT App Inventor Community. Available at: <https://community.appinventor.mit.edu/t/esp32-wifi-webserver-led-on-off-static-ip-soft-access-point/9323> [Accessed 27 December 2021].
Hexler.net. 2021. Introduction · TouchOSC | hexler.net. [online] Available at: <https://hexler.net/touchosc/manual/introduction> [Accessed 27 December 2021].
Forum.aemodular.com. 2022. OSC to CV with an ESP32 (TouchOSC) | AE Modular. [online] Available at: <https://forum.aemodular.com/thread/1887/osc-cv-esp32-touchosc> [Accessed 10 January 2022].
Teja, R., 2021. In-depth ESP32 PWM Tutorial | How to use PWM in ESP32?. [online] Electronics Hub. Available at: <https://www.electronicshub.org/esp32-pwm-tutorial/> [Accessed 11 January 2022].
