Explore a conference talk from RubyConf 2021 that delves into PicoRuby, an alternative implementation of the mruby interpreter for one-chip microcontrollers, and PRK Firmware, the world's first keyboard firmware framework in Ruby. Learn how to write custom keymaps and configure additional behavior using Ruby's features like open class system and Proc objects. Discover the potential of Ruby as a scripting language for microcontrollers, comparable to MicroPython, CircuitPython, or Lua. Gain insights into keyboard building, including keycap selection and firmware installation. Witness demonstrations of Fibonacci sequences and password generators in keymap.rb. Understand the architecture, multitasking capabilities, and memory optimization techniques used in PicoRuby and PRK Firmware. Explore the challenges and solutions in creating a small Ruby compiler for embedded applications, including RAM consumption and memory allocation strategies.