And here it is...a dual 4-Stage envelope generator 8HP Eurorack. 2xADSR is a dual envelope module in 8HP Eurorack format based on the Arturia Minibrute. The schematics are openly published on the internet, so it would seem reasonable to have adapted a fun DIY panel/pcb project for educational purposes under fair use. Each envelope is an independent Attack-Decay-Sustain-Release linear contour. Each envelope takes a gate input, puts out a positive-voltage contour and a buffered negative-voltage (DC inverted) contour.
This is a DIY project, just a pcb/panel only, with surface-mount soldering required. You supply the parts components (not included), but it uses all very affordable and easy-to-find parts. I would not recommend this as your very first SMT build, maybe your 2nd or 3rd SMT build though. The BOM and Schematics for this project can be found on muffwiggler
PCB/panel are available in my Reverb Store