Maker Eirik Brandal has put collectively a circuit sculpture, dubbed cwymriad, which mixes sound and lightweight to visualise ring-modulated audio generated by an Espressif ESP32 microcontroller — a follow-up to the sooner audio-only ioalieia and maze-like ddrysfeöd.
“‘Cwymriad’ relies on a twin ring modulation circuit by which the ESP32 creates each the provider and modulation indicators,” Brandal explains of his newest creation. “The sq. wave output of the ESP is filtered right down to one thing resembling a triangle wave and mixed within the ring modulator earlier than the ensuing sign is shipped by means of an echo impact, after which despatched again to the ESP32’s inside ADC in order that it may be displayed on the LED matrix.”
Like his earlier initiatives, the sculpture is put along with elements floating in mid-air — suspended on wires that double because the circuit traces themselves. It isn’t an entirely free-form circuit sculpture, nonetheless: Key elements, together with the LED matrix and the speaker, are housed in or mounted on acrylic.
The cwymriad sculpture — Welsh for “collapse” — is not Brandal’s first enterprise into microcontroller-driven audio initiatives: Its direct precursor was ddrysfeöd — maze — which lights up sections of a labyrinth in time to the generated music. Ioalieia, in the meantime, had no visible ingredient — however does represented Brandal’s first go at constructing a speaker enclosure. “I did not have excessive hopes for it,” he writes, “and was anticipating it to have a a lot sharper resonance frequency, nevertheless it turned out fantastic.
“I am utilizing an MCP4251 digital potentiometer to perform as a type of voltage managed amplifier, besides that the management voltage envelope is created within the code of the ESP and transferred to the digital pot by way of SPI,” Brandal writes of his newest construct
“Ring modulation in itself is in fact fairly much like amplitude modulation, however right here the digital pot is doing the amount management, whereas the ring modulator is creating the bell-like sounds out of solely a few oscillators. I am utilizing a PT2399 echo chip to offer some depth to the sound, and the entire thing is amplified by two bridged LM380 chips, whereas the LED matrix is pushed by a couple of MAX7219s.”
Extra particulars on the construct, together with a schematic, can be found on Brandal’s Hackaday.io venture web page.