Getting Started with arduino
Leonardo 6 dollar board will get you going was easy to clean the pcb and it works with HID device emulation like keyboard / mouse / joystick. if you want more get the x86 sam boards
Arduino projects and links.
esp8266 door bell writeup / review
https://subversion.nexusuk.org/projects/doorbell door bell repository from a different project. same effect.
knock sensor / clap peizo sensors / mic
drum shoes for making midi signals.
LED heart rate(pulse) detector
servo / stepper controll
digi weight scale hack for part of the bar bot.
melzi 3d printer board
various electronics ebay parts worth buying with price charts.
https://klamfx.wordpress.com/2017/01/27/fixing-upload-problem-with-arduino-uno-clone-with-ch340-on-linux/ << apparently this is why… i had issues with 2 other esp8266 programmers and a esp8266 r1d2 clone with 32mb of flash.
the mini r1d2 worked and the red pcb with a little switch on them, add hotglue to make the switch more rigid.
esp8285 is better option for the esp-01 style boards because it needs no modifications to do deepsleep power saving.
https://github.com/earlephilhower/ESP8266SAM speech synthesizer for arduino
https://github.com/Matheus-Garbelini/esp32_esp8266_attacks beware of security issues when designing.