An unlucky consequence of the fast improvement of expertise is the fast tempo at which digital units grow to be out of date. We regularly see very well-made {hardware} find yourself lined in mud inside only a few years, as a result of the underlying expertise is now not related. To save lots of that high-quality {hardware} from the e-waste mountains of the world, many manufacturers get artistic and switch to upcycling. That’s how bitluni was in a position to revive a classic audio management panel as a contemporary ESP32-controlled music sequencer/synthesizer.
Whereas attending the Hackaday Supercon in California this yr, bitluni visited the Apex Electronics Surplus retailer in LA. That retailer has an enormous number of previous digital units and elements, the place bitluni discovered a management panel from a ‘90s audio workstation. That may have been a really high-end workstation for skilled audio engineers that contained a number of of those management panels. Every panel has 16 rotary encoders in a 4×4 grid. Each encoder has its personal four-digit VFD-style show and mode button with LED indicator, and the encoder knobs even have an outer ring of LEDs to point out quantity, amplitude, depth, or anything. Lastly, each column has a keypad on the backside with 12 buttons, every with an LED indicator.
That’s plenty of good {hardware} in a compact interface, making it fairly fascinating. Bitluni and a pal at Hackaday each began reverse-engineering the gadget, with that pal (Jeoen Domburg, AKA “Spritetm”) unlocking every thing by getting access to the FPGA (Area-Programmable Gate Array) controller. With that entry, bitluni was ready to make use of the controls nevertheless he preferred.
To realize that, bitluni designed a customized PCB that plugs into the management panel’s bus interface. That PCB incorporates an ESP32 microcontroller that reads button presses and encoder positions, and in addition units the shows and LEDs. He selected to make use of the ESP32 to create a synthesizer/sampler sequencer that makes use of the knobs and buttons to play both synthesized tones or sampled WAV recordsdata in repeating patterns. The ESP32 outputs audio as 1-bit, as a result of a lot of the microcontroller’s pins had been wanted to interface with the panel. The standard isn’t nice, nevertheless it has a pleasant lo-fi sound that’s interesting for sure music.
Bitluni initially pushed that audio output by means of a small amplifier board to a speaker, however that lowered the standard even additional. He ended up feeding the audio as a line-out sign, which he can connect with an exterior speaker system or his digicam’s mic enter. As you possibly can hear on the finish of his video, this works fairly effectively and was surprisingly inexpensive to construct utilizing this in any other case out of date piece of classic tech.
