As I wrote in the introduction section, I started this project by hacking together a discarded scale, an ESP32 dev board (Lolin32 clone), a HX711 breakout board, and a monochrome 0.96" OLED screen. At first, I used the serial port for mode changes, etc., but soon after I added a few buttons for menu navigation and typical counter-top scale functions such as Tare and unit swap (g, kg, pound). The display also seemed a bit crammed on a single 0.96" screen (128x64), so I added a second one - now one screen displays measured weight, and the other can display, for example, the currently selected ingredient I pulled from my formula spreadsheet, and it's relative percentage. 

As this first update on the project is about the prototyping setup I use, I created a Fritzing breadboard scheme so others can follow along. I couldn't find a load cell object, so I created my own - you can find that in the files section above, if you're interested. Also, I used simpler OLED I2C screen objects, since they're much easier to handle than the 6 pin versions I have. With the 6 pin versions, the board is configured for SPI but does not break out the CS pin, and changing to I2C is quite a pain.  

For the firmware, I settled on developing it using Visual Studio code with the Arduino extension (+ Arduino-ESP32 core), I find it much nicer to use than the Arduino IDE. 

I hope to have the firmware stable enough by end of next week. Then I can go into more detail about the code, and maybe even start with mechanical + electronic design considerations.