diff --git a/Code/devterm_keyboard/debouncer.h b/Code/devterm_keyboard/debouncer.h
deleted file mode 100644
index dc36f17..0000000
--- a/Code/devterm_keyboard/debouncer.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#ifndef DEBOUNCER_H
-#define DEBOUNCER_H
-
-#include <cstdint>
-
-typedef uint8_t millis_t;
-
-const millis_t DEBOUNCE_MS = 5;
-
-/**
-   @brief Asymmetric debouncer
-*/
-class Debouncer {
-  public:
-    Debouncer();
-    void updateTime(millis_t delta);
-    bool sample(bool value);
-  private:
-    millis_t timeout;
-};
-
-template<typename T, T millis>
-class Timeout {
-  public:
-    Timeout() {
-      timeout = 0;
-    }
-
-    void updateTime(millis_t delta) {
-      if (timeout > delta) {
-        timeout -= delta;
-      } else {
-        timeout = 0;
-      }
-    }
-
-    void expire() {
-      timeout = 0;
-    }
-
-    bool get() const {
-      return timeout == 0;
-    }
-
-    void reset() {
-      timeout = millis;
-    }
-  private:
-    uint16_t timeout;
-};
-
-
-#endif
diff --git a/Code/devterm_keyboard/debouncer.ino b/Code/devterm_keyboard/debouncer.ino
deleted file mode 100644
index 93cd13d..0000000
--- a/Code/devterm_keyboard/debouncer.ino
+++ /dev/null
@@ -1,23 +0,0 @@
-#include "debouncer.h"
-
-Debouncer::Debouncer()
-  : timeout(0)
-{
-}
-
-void Debouncer::updateTime(millis_t delta) {
-  if (timeout > delta) {
-    timeout -= delta;
-  } else {
-    timeout = 0;
-  }
-}
-
-bool Debouncer::sample(bool value) {
-  if (value || timeout == 0) {
-    timeout = DEBOUNCE_MS;
-    return true;
-  }
-
-  return false;
-}
diff --git a/Code/devterm_keyboard/glider.h b/Code/devterm_keyboard/glider.h
deleted file mode 100644
index f4f9785..0000000
--- a/Code/devterm_keyboard/glider.h
+++ /dev/null
@@ -1,29 +0,0 @@
-#ifndef GLIDER_H
-#define GLIDER_H
-
-#include <cstdint>
-
-
-class Glider {
-public:
-  Glider();
-  void setDirection(int8_t);
-  void update(float velocity, uint16_t sustain);
-  void updateSpeed(float velocity);
-  void stop();
-
-  struct GlideResult {
-    int8_t value;
-    bool stopped;
-  };
-  GlideResult glide(uint8_t delta);
-
-public:
-  int8_t direction;
-  float speed;
-  uint16_t sustain;
-  uint16_t release;
-  float error;
-};
-
-#endif
diff --git a/Code/devterm_keyboard/glider.ino b/Code/devterm_keyboard/glider.ino
deleted file mode 100644
index 8ecb221..0000000
--- a/Code/devterm_keyboard/glider.ino
+++ /dev/null
@@ -1,60 +0,0 @@
-#include <cmath>
-
-#include "glider.h"
-#include "math.h"
-
-Glider::Glider()
-: speed(0),
-  sustain(0),
-  release(0),
-  error(0)
-{}
-
-void Glider::setDirection(int8_t direction) {
-  if (this->direction != direction) {
-    stop();
-  }
-  this->direction = direction;
-}
-
-void Glider::update(float speed, uint16_t sustain) {
-  this->speed = speed;
-  this->sustain = sustain;
-  this->release = sustain;
-}
-
-void Glider::updateSpeed(float speed) {
-  this->speed = speed;
-}
-
-void Glider::stop() {
-  this->speed = 0;
-  this->sustain = 0;
-  this->release = 0;
-  this->error = 0;
-}
-
-Glider::GlideResult Glider::glide(millis_t delta) {
-  const auto alreadyStopped = speed == 0;
-
-  error += speed * delta;
-  int8_t distance = 0;
-  if (error > 0) {
-    distance = clamp<int8_t>(std::ceil(error));
-  }
-  error -= distance;
-
-  if (sustain > 0) {
-    const auto sustained = min(sustain, (uint16_t)delta);
-    sustain -= sustained;
-  } else if (release > 0) {
-    const auto released = min(release, (uint16_t)delta);
-    speed = speed * (release - released) / release;
-    release -= released;
-  } else {
-    speed = 0;
-  }
-
-  const int8_t result = direction * distance;
-  return GlideResult { result, !alreadyStopped && speed == 0 };
-}
diff --git a/Code/devterm_keyboard/ratemeter.h b/Code/devterm_keyboard/ratemeter.h
deleted file mode 100644
index 451b189..0000000
--- a/Code/devterm_keyboard/ratemeter.h
+++ /dev/null
@@ -1,38 +0,0 @@
-#ifndef RATEMETER_H
-#define RATEMETER_H
-
-#include <cstdint>
-
-#include "debouncer.h"
-
-class RateMeter {
-public:
-  RateMeter();
-  void onInterrupt();
-  void tick(millis_t delta);
-  void expire();
-
-  uint16_t delta() const;
-  // Hall sensor edges per seconds.
-  // stopped: 0
-  // really slow => ~3
-  // medium => ~30
-  // fast => < 300
-  // max => 1000
-  float rate() const;
-
-private:
-  uint32_t lastTime;
-
-  // really Range, emperically:
-  // fast => < 5_000 us,
-  // medium => 20_000 - 40_000 us
-  // really slow => 250_000 us
-  uint32_t averageDelta;
-
-  static const uint16_t CUTOFF_MS = 1000;
-  // Cut off after some seconds to prevent multiple timestamp overflow (~70 mins)
-  Timeout<uint16_t, CUTOFF_MS> cutoff;
-};
-
-#endif
diff --git a/Code/devterm_keyboard/ratemeter.ino b/Code/devterm_keyboard/ratemeter.ino
deleted file mode 100644
index bcc3528..0000000
--- a/Code/devterm_keyboard/ratemeter.ino
+++ /dev/null
@@ -1,47 +0,0 @@
-#include <Arduino.h>
-#include <cstdint>
-
-#include "ratemeter.h"
-#include "math.h"
-
-RateMeter::RateMeter()
-: lastTime(0)
-{}
-
-void RateMeter::onInterrupt() {
-  const auto now = millis();
-  if (cutoff.get()) {
-    averageDelta = CUTOFF_MS;
-  } else {
-    const auto delta = getDelta(lastTime, now, CUTOFF_MS);
-    averageDelta = (averageDelta + delta) / 2;
-  }
-  lastTime = now;
-  cutoff.reset();
-}
-
-void RateMeter::tick(millis_t delta) {
-  cutoff.updateTime(delta);
-  if (!cutoff.get()) {
-    averageDelta += delta;
-  }
-}
-
-void RateMeter::expire() {
-  cutoff.expire();
-}
-
-uint16_t RateMeter::delta() const {
-  return averageDelta;
-}
-
-float RateMeter::rate() const {
-  if (cutoff.get()) {
-    return 0.0f;
-  } else if (averageDelta == 0) {
-    // to ensure range 0 ~ 1000.0
-    return 1000.0f;
-  } else {
-    return 1000.0f / (float)averageDelta;
-  }
-}