The Drone Machine is a 5-voice DIY synthesizer built on the On Board sProject PCB. Powered by an ESP32-S3 microcontroller with audio out via a stereo I2S DAC board, the Drone Machine takes advantage of the sProject’s capacitive touch pads for triggering tones, and potentiometers are used to adjust features of each tone such as frequency, release time, timbre, vibrato, drive, delay and reverb. An OLED screen displays the current parameter values a sounding voice levels.
The sound of the On Board Drone Machine ranges from a pure triangle wave to various FM tones and can be made more aggressive with overdrive and delay feedback.
Software for the Drone Machine was written by Andrew R. Brown using the M16 audio synthesis library.
Above is an image of the Drone Machine version 1 – which has suffered a bit of wear and tear through use and testing.
Like all sProject PCB designs, the Drone Machine is DIY assembled from a kit. Workshops for building Drone Machines have been run since 2023. Below are some photos from these workshops.