An unlucky consequence of the fast growth of expertise is the fast tempo at which digital gadgets grow to be out of date. We regularly see very well-made {hardware} find yourself coated in mud inside just some years, as a result of the underlying expertise is 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 12 months, bitluni visited the Apex Electronics Surplus retailer in LA. That retailer has a large number of previous digital gadgets and elements, the place bitluni discovered a management panel from a ‘90s audio workstation. That might 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 indicate quantity, amplitude, depth, or anything. Lastly, each column has a keypad on the backside with 12 buttons, every with an LED indicator.
That’s quite a lot of good {hardware} in a compact interface, making it fairly fascinating. Bitluni and a buddy at Hackaday each began reverse-engineering the machine, with that buddy (Jeoen Domburg, AKA “Spritetm”) unlocking every thing by getting access to the FPGA (Discipline-Programmable Gate Array) controller. With that entry, bitluni was ready to make use of the controls nevertheless he favored.
To realize that, bitluni designed a customized PCB that plugs into the management panel’s bus interface. That PCB comprises an ESP32 microcontroller that reads button presses and encoder positions, and likewise 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 many of the microcontroller’s pins had been wanted to interface with the panel. The standard isn’t nice, but it surely 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 hook up with an exterior speaker system or his digital camera’s mic enter. As you possibly can hear on the finish of his video, this works fairly nicely and was surprisingly inexpensive to construct utilizing this in any other case out of date piece of classic tech.