diff --git a/src-slider_io/src/controller_state.rs b/src-slider_io/src/controller_state.rs
index cc30383..733f5e1 100644
--- a/src-slider_io/src/controller_state.rs
+++ b/src-slider_io/src/controller_state.rs
@@ -1,13 +1,25 @@
 use parking_lot::Mutex;
 use std::{sync::Arc, time::Instant};
 
+/// Stores the input state of a slider controller, including ground touch pads,
+/// air strings and extra buttons.
 pub struct ControllerState {
+  /// Represents touch pressure in 32 touch pads in a 2 tall and 16 wide grid.
+  /// Each pressur is in a `u8` from 0 to 255. Pads are represented in order of
+  /// bottom left, then top left, then flows from left to right.
   pub ground_state: [u8; 32],
+
+  /// Represents air string state in 6 pads starting from bottom to top. 0 means
+  /// uninterrupted, 1 means interrupted.
   pub air_state: [u8; 6],
+
+  /// Represents extra button state, usually used for coin/test/card entry
+  /// functions.
   pub extra_state: [u8; 3],
 }
 
 impl ControllerState {
+  /// Make a blank input state.
   pub fn new() -> Self {
     Self {
       ground_state: [0; 32],
@@ -16,11 +28,13 @@ impl ControllerState {
     }
   }
 
-  pub fn flat(&self, sensitivity: &u8) -> Vec<bool> {
+  /// Converts an input state to a `Vec<bool>`, used for output simulation and
+  /// visualisation.
+  pub fn to_flat(&self, sensitivity: &u8) -> Vec<bool> {
     self
       .ground_state
       .iter()
-      .map(|x| x > sensitivity)
+      .map(|x| x >= sensitivity)
       .chain(
         self
           .air_state
@@ -31,6 +45,9 @@ impl ControllerState {
       .collect()
   }
 
+  /// Flips the ground slider state vertically. Used when taking input for
+  /// tasoller controllers as they report starting from top left (instead of
+  /// botton left that is used internally).
   pub fn flip_vert(&mut self) {
     for i in 0..16 {
       self.ground_state.swap(i * 2, i * 2 + 1);
@@ -38,13 +55,21 @@ impl ControllerState {
   }
 }
 
+// Stores the lighting state of a slider controller.
 pub struct LedState {
+  /// Represents the RGB pixel values of the slider controller from left to
+  /// right. Alternates between 16 touch pad pixels and 15 divider pixels.
   pub led_state: [u8; 3 * 31],
+
+  /// Internal dirty flag used to indicate that new lighting data is available.
   pub dirty: bool,
+
+  /// To deprecate
   pub start: Instant,
 }
 
 impl LedState {
+  /// Make a blank lighting state.
   pub fn new() -> Self {
     Self {
       led_state: [0; 3 * 31],
@@ -53,17 +78,25 @@ impl LedState {
     }
   }
 
+  /// Apply a RGB color to some pixel in the lighting state.
   pub fn paint(&mut self, idx: usize, color: &[u8; 3]) {
     self.led_state[3 * idx..3 * (idx + 1)].copy_from_slice(color);
   }
 }
 
+/// Stores data required for a single slider controller. Data and lighting
+/// states are stored seperately in their own `Arc<Mutex<T>>` so that they can
+/// be locked independently.
 pub struct FullState {
+  /// Input data for the slider controller.
   pub controller_state: Arc<Mutex<ControllerState>>,
+
+  /// Lighting data for the slider controller.
   pub led_state: Arc<Mutex<LedState>>,
 }
 
 impl FullState {
+  /// Creates a blank slider controller state
   pub fn new() -> Self {
     Self {
       controller_state: Arc::new(Mutex::new(ControllerState::new())),
@@ -71,14 +104,8 @@ impl FullState {
     }
   }
 
-  pub fn clone_controller(&self) -> Arc<Mutex<ControllerState>> {
-    Arc::clone(&self.controller_state)
-  }
-
-  pub fn clone_led(&self) -> Arc<Mutex<LedState>> {
-    Arc::clone(&self.led_state)
-  }
-
+  /// Takes an instantaneous slider controller state (input + lighting) as a
+  /// `Vec<u8>` that can be used for visualisation.
   pub fn snapshot(&self) -> Vec<u8> {
     let mut buf: Vec<u8> = vec![];
     {
@@ -99,8 +126,8 @@ impl FullState {
 impl Clone for FullState {
   fn clone(&self) -> Self {
     Self {
-      controller_state: self.clone_controller(),
-      led_state: self.clone_led(),
+      controller_state: Arc::clone(&self.controller_state),
+      led_state: Arc::clone(&self.led_state),
     }
   }
 }