QMK and Keyboards

Quantum Mechanical Keyboard (QMK) is a popular open source firmware for custom keyboards. Who knew a keyboard could do so much?
See my keymap on GitHub. Please feel free to open an issue or start a discussion about any problems, questions, or comments.
QMK feature libraries
Achordion – customize the tap-hold decision
Autocorrection – run rudimentary autocorrection on your keyboard
Caps Word – modern alternative to Caps Lock
Custom shift keys – they’re surprisingly tricky to get right; here is my approach
Layer Lock key – macro to stay in the current layer
Mouse Turbo Click – macro that clicks the mouse rapidly
Repeat Key – an extensible “repeat last key” implementation
Sentence Case – automatically capitalize the first letter of sentences
Word selection – macro for convenient word or line selection
QMK
Macro buttons – an assortment of practical QMK macros
Triggers: reacting to interesting events – layer changes, tap vs. long press, etc.
Typing non-English letters – several approaches to type symbols like ä, ç, λ
QMK song player – play QMK song code in your browser
General
Alt keyboard layouts – switching from QWERTY to an alternative keyboard layout
Designing a symbol layer – ergonomic and character frequency considerations
PSA: Thumbs can get overuse injuries – anecdotes, common injuries, countermeasures
Questioning the ergonomics of 40% keyboards – smaller ≠ better
Keyboard FAQs – thoughts on topics that come up regularly
Links about keyboards – interesting links about keyboards and related topics