diff --git a/src/config.rs b/src/config.rs
index e962e4d..ac685d2 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,10 +1,9 @@
-use crate::patterns::PixelColor;
+use crate::pixel_color::PixelColor;
 use crate::runner::DeviceSequence;
 use serde_derive::{Deserialize, Serialize};
 use std::collections::HashSet;
 use std::fs;
 
-
 #[derive(Serialize, Deserialize)]
 pub struct Config<const N: usize> {
     devices: Vec<Device<N>>,
diff --git a/src/main.rs b/src/main.rs
index 98618f5..911e409 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ mod audio;
 mod bluetooth;
 mod config;
 mod patterns;
+mod pixel_color;
 mod runner;
 mod spectacle;
 
diff --git a/src/patterns.rs b/src/patterns.rs
index cf3e76b..d99377f 100644
--- a/src/patterns.rs
+++ b/src/patterns.rs
@@ -25,11 +25,9 @@ use crate::patterns::ring::Ring;
 use crate::patterns::ring_scanner::RingScanner;
 use crate::patterns::scanner::Scanner;
 use crate::patterns::stars_random::StarsRandom;
-use rand::rngs::ThreadRng;
-use rand::Rng;
+use crate::pixel_color::PixelColor;
 use serde_derive::{Deserialize, Serialize};
-use std::fmt;
-use std::ops::{Add, AddAssign, Div, Index, IndexMut, Sub, SubAssign};
+use std::ops::{Index, IndexMut};
 
 #[derive(Serialize, Deserialize, Debug, Eq, Hash, PartialEq, Copy, Clone)]
 #[serde(tag = "type")]
@@ -49,6 +47,11 @@ pub(crate) enum Patterns<const N: usize> {
     StarsRandom(StarsRandom<N>),
 }
 
+/// Pattern that have to be implemented
+///
+///
+///
+///
 pub trait Pattern: Iterator {
     type Strip;
 
@@ -151,108 +154,6 @@ impl<const N: usize> Pattern for Patterns<N> {
     }
 }
 
-///
-/// a struct for an RGB color
-#[derive(Clone, Copy, Debug, Serialize, Deserialize, Default, Eq, Hash, PartialEq)]
-pub struct PixelColor {
-    pub(crate) red: u8,
-    pub(crate) green: u8,
-    pub(crate) blue: u8,
-}
-
-impl fmt::Display for PixelColor {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "[{},{},{}]", self.red, self.green, self.blue)
-    }
-}
-
-impl Div<u8> for PixelColor {
-    type Output = PixelColor;
-
-    fn div(self, rhs: u8) -> Self::Output {
-        PixelColor {
-            red: self.red / rhs,
-            green: self.green / rhs,
-            blue: self.blue / rhs,
-        }
-    }
-}
-
-impl Add for PixelColor {
-    type Output = Self;
-
-    fn add(self, rhs: Self) -> Self::Output {
-        PixelColor {
-            red: self.red.saturating_add(rhs.red),
-            green: self.green.saturating_add(rhs.green),
-            blue: self.blue.saturating_add(rhs.blue),
-        }
-    }
-}
-
-impl Sub<u8> for PixelColor {
-    type Output = Self;
-
-    fn sub(self, rhs: u8) -> Self::Output {
-        PixelColor {
-            red: self.red.saturating_sub(rhs),
-            green: self.green.saturating_sub(rhs),
-            blue: self.blue.saturating_sub(rhs),
-        }
-    }
-}
-
-impl SubAssign for PixelColor {
-    fn sub_assign(&mut self, rhs: Self) {
-        self.red = self.red.saturating_sub(rhs.red);
-        self.green = self.red.saturating_sub(rhs.green);
-        self.blue = self.red.saturating_sub(rhs.blue);
-    }
-}
-
-impl AddAssign for PixelColor {
-    fn add_assign(&mut self, rhs: Self) {
-        self.red = self.red.saturating_add(rhs.red);
-        self.green = self.red.saturating_add(rhs.green);
-        self.blue = self.red.saturating_add(rhs.blue);
-    }
-}
-
-impl PixelColor {
-    /// apply random delta to pixel and return computed value
-    ///
-    /// # Arguments
-    ///
-    /// * `pixel`: pixel to apply delta
-    /// * `stability`: amplitude of delta between 0 and `stability`
-    ///
-    /// returns: PixelColor
-    ///
-    pub fn random_delta(&self, stability: usize, rng: &mut ThreadRng) -> PixelColor {
-        let minus_interval = -(stability as i8);
-        let max_interval = stability as i8;
-        let red_delta = rng.gen_range(minus_interval..max_interval) as i8;
-        let green_delta = rng.gen_range(minus_interval..max_interval) as i8;
-        let blue_delta = rng.gen_range(minus_interval..max_interval) as i8;
-        self.delta((red_delta, green_delta, blue_delta))
-    }
-
-    pub fn delta(&self, delta: (i8, i8, i8)) -> PixelColor {
-        let (red, green, blue) = delta;
-        PixelColor {
-            red: (self.red as i16 + red as i16) as u8,
-            green: (self.green as i16 + green as i16) as u8,
-            blue: (self.blue as i16 + blue as i16) as u8,
-        }
-    }
-
-    pub fn is_closer(&self, pixel: PixelColor, distance: PixelColor) -> bool {
-        (self.red as i16 - pixel.red as i16).abs() <= distance.red as i16
-            && (self.green as i16 - pixel.green as i16).abs() <= distance.green as i16
-            && (self.blue as i16 - pixel.blue as i16).abs() <= distance.blue as i16
-    }
-}
-
 ///
 /// a basic newtype based on a fix array size.
 ///
diff --git a/src/patterns/color_wipe.rs b/src/patterns/color_wipe.rs
index 279c050..73b9bd6 100644
--- a/src/patterns/color_wipe.rs
+++ b/src/patterns/color_wipe.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_init_background, impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/fade.rs b/src/patterns/fade.rs
index b928697..c3873f9 100644
--- a/src/patterns/fade.rs
+++ b/src/patterns/fade.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::Strip;
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/fill_random.rs b/src/patterns/fill_random.rs
index f159a9d..305c325 100644
--- a/src/patterns/fill_random.rs
+++ b/src/patterns/fill_random.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/fill_unstable.rs b/src/patterns/fill_unstable.rs
index 1b77fe6..a87b8b3 100644
--- a/src/patterns/fill_unstable.rs
+++ b/src/patterns/fill_unstable.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/rain.rs b/src/patterns/rain.rs
index e564906..d8d9350 100644
--- a/src/patterns/rain.rs
+++ b/src/patterns/rain.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_last_iteration, Strip};
 use rand::Rng;
 use serde::{Deserialize, Serialize};
diff --git a/src/patterns/rainbow.rs b/src/patterns/rainbow.rs
index d3bec86..70d98a1 100644
--- a/src/patterns/rainbow.rs
+++ b/src/patterns/rainbow.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/ring.rs b/src/patterns/ring.rs
index d8b58cb..03cfef9 100644
--- a/src/patterns/ring.rs
+++ b/src/patterns/ring.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_init_background, impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/ring_scanner.rs b/src/patterns/ring_scanner.rs
index f533413..804c8bd 100644
--- a/src/patterns/ring_scanner.rs
+++ b/src/patterns/ring_scanner.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_init_background, impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/scanner.rs b/src/patterns/scanner.rs
index cbf72cd..e5a9088 100644
--- a/src/patterns/scanner.rs
+++ b/src/patterns/scanner.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_init_background, impl_pattern_last_iteration, Strip};
 use serde::{Deserialize, Serialize};
 
diff --git a/src/patterns/stars_random.rs b/src/patterns/stars_random.rs
index 30c4f30..75c77f9 100644
--- a/src/patterns/stars_random.rs
+++ b/src/patterns/stars_random.rs
@@ -1,4 +1,5 @@
-use crate::patterns::{Pattern, PixelColor};
+use crate::patterns::Pattern;
+use crate::pixel_color::PixelColor;
 use crate::{impl_pattern_last_iteration, Strip};
 use rand::Rng;
 use serde::{Deserialize, Serialize};
@@ -26,14 +27,13 @@ impl<const N: usize> Pattern for StarsRandom<N> {
     fn init(&mut self) -> Option<Self::Strip> {
         if let Some(color) = self.background_color {
             self.strip = Strip::<N>::new(color);
-            let red = (self.color.red as i16 - color.red as i16) as i8;
-            let green = (color.green as i16 - self.color.green as i16) as i8;
-            let blue = (self.color.blue as i16 - color.blue as i16) as i8;
-            println!("{} {} {}", red, green, blue);
+            let red = (self.color.red as i16 - color.red as i16);
+            let green = (color.green as i16 - self.color.green as i16);
+            let blue = (self.color.blue as i16 - color.blue as i16);
             self.step = (
-                red / self.steps as i8,
-                green / self.steps as i8,
-                blue / self.steps as i8,
+                -(red / self.steps as i16) as i8,
+                -(green / self.steps as i16) as i8,
+                -(blue / self.steps as i16) as i8,
             );
             Some(self.strip)
         } else {
@@ -59,10 +59,8 @@ impl<const N: usize> Iterator for StarsRandom<N> {
         let mut rng = rand::thread_rng();
         for i in 0..N {
             let current_color = self.strip[i];
-            if current_color == self.background_color {
-                if rng.gen_bool(1.0 / self.ratio as f64) {
-                    self.strip[i] = Some(self.color);
-                }
+            if rng.gen_bool(1.0 / self.ratio as f64) {
+                self.strip[i] = Some(self.color);
             } else {
                 let color = current_color.unwrap();
                 let background = self.background_color.unwrap_or(PixelColor::default());
diff --git a/src/pixel_color.rs b/src/pixel_color.rs
new file mode 100644
index 0000000..69501e5
--- /dev/null
+++ b/src/pixel_color.rs
@@ -0,0 +1,122 @@
+use rand::prelude::ThreadRng;
+use rand::Rng;
+use serde_derive::{Deserialize, Serialize};
+use std::fmt;
+use std::ops::{Add, AddAssign, Div, Sub, SubAssign};
+
+///
+/// a struct for an RGB color
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, Default, Eq, Hash, PartialEq)]
+pub struct PixelColor {
+    pub(crate) red: u8,
+    pub(crate) green: u8,
+    pub(crate) blue: u8,
+}
+
+impl fmt::Display for PixelColor {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[{},{},{}]", self.red, self.green, self.blue)
+    }
+}
+
+impl Div<u8> for PixelColor {
+    type Output = PixelColor;
+
+    fn div(self, rhs: u8) -> Self::Output {
+        PixelColor {
+            red: self.red / rhs,
+            green: self.green / rhs,
+            blue: self.blue / rhs,
+        }
+    }
+}
+
+impl Add for PixelColor {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        PixelColor {
+            red: self.red.saturating_add(rhs.red),
+            green: self.green.saturating_add(rhs.green),
+            blue: self.blue.saturating_add(rhs.blue),
+        }
+    }
+}
+
+impl Sub<u8> for PixelColor {
+    type Output = Self;
+
+    fn sub(self, rhs: u8) -> Self::Output {
+        PixelColor {
+            red: self.red.saturating_sub(rhs),
+            green: self.green.saturating_sub(rhs),
+            blue: self.blue.saturating_sub(rhs),
+        }
+    }
+}
+
+impl SubAssign for PixelColor {
+    fn sub_assign(&mut self, rhs: Self) {
+        self.red = self.red.saturating_sub(rhs.red);
+        self.green = self.red.saturating_sub(rhs.green);
+        self.blue = self.red.saturating_sub(rhs.blue);
+    }
+}
+
+impl AddAssign for PixelColor {
+    fn add_assign(&mut self, rhs: Self) {
+        self.red = self.red.saturating_add(rhs.red);
+        self.green = self.red.saturating_add(rhs.green);
+        self.blue = self.red.saturating_add(rhs.blue);
+    }
+}
+
+impl PixelColor {
+    /// apply random delta to pixel and return computed value
+    ///
+    /// # Arguments
+    ///
+    /// * `pixel`: pixel to apply delta
+    /// * `stability`: amplitude of delta between 0 and `stability`
+    ///
+    /// returns: PixelColor
+    ///
+    pub fn random_delta(&self, stability: usize, rng: &mut ThreadRng) -> PixelColor {
+        let minus_interval = -(stability as i8);
+        let max_interval = stability as i8;
+        let red_delta = rng.gen_range(minus_interval..max_interval) as i8;
+        let green_delta = rng.gen_range(minus_interval..max_interval) as i8;
+        let blue_delta = rng.gen_range(minus_interval..max_interval) as i8;
+        self.delta((red_delta, green_delta, blue_delta))
+    }
+
+    pub fn delta(&self, delta: (i8, i8, i8)) -> PixelColor {
+        let (red, green, blue) = delta;
+
+        let red = self.red as i16 + red as i16;
+        let green = self.green as i16 + green as i16;
+        let blue = self.blue as i16 + blue as i16;
+
+        let bound = |color: i16| {
+            if color < 0 {
+                0
+            } else if color > 255 {
+                255
+            } else {
+                color as u8
+            }
+        };
+
+        PixelColor {
+            red: bound(red),
+            green: bound(green),
+            blue: bound(blue),
+        }
+    }
+
+    pub fn is_closer(&self, pixel: PixelColor, distance: PixelColor) -> bool {
+        (self.red as i16 - pixel.red as i16).abs() <= distance.red as i16
+            && (self.green as i16 - pixel.green as i16).abs() <= distance.green as i16
+            && (self.blue as i16 - pixel.blue as i16).abs() <= distance.blue as i16
+    }
+}
diff --git a/src/runner.rs b/src/runner.rs
index 2db4758..386c826 100644
--- a/src/runner.rs
+++ b/src/runner.rs
@@ -1,5 +1,6 @@
 use crate::config::Device;
-use crate::patterns::{Pattern, Patterns, PixelColor};
+use crate::patterns::{Pattern, Patterns};
+use crate::pixel_color::PixelColor;
 use crate::Strip;
 use bluer::Address;
 use serde::{Deserialize, Serialize};
@@ -41,7 +42,16 @@ pub struct Context<const N: usize> {
 
 pub(crate) type DeviceSequence<const N: usize> = Vec<Context<N>>;
 
-pub async fn runner_loop<const N: usize>(runner: DeviceSequence<N>, tx: Sender<Strip<N>>) {
+/// iterate over `runner` and stream strip data to `tx` channel
+///
+/// # Arguments
+///
+/// * `runner`: Sequence to stream
+/// * `tx`: channel to stream data to
+///
+/// returns: ()
+///
+async fn runner_loop<const N: usize>(runner: DeviceSequence<N>, tx: Sender<Strip<N>>) {
     let mut background = Strip::<N>::default();
     for mut context in runner {
         let mut strip = context.pattern.init().unwrap_or(background);
@@ -59,7 +69,7 @@ pub async fn runner_loop<const N: usize>(runner: DeviceSequence<N>, tx: Sender<S
     }
 }
 
-pub fn apply_mask<const N: usize>(previous_strip: Strip<N>, strip: Strip<{ N }>) -> Strip<N> {
+fn apply_mask<const N: usize>(previous_strip: Strip<N>, strip: Strip<{ N }>) -> Strip<N> {
     let mut new_strip = Strip::default();
     for i in 0..N {
         if let Some(color) = strip[i] {
@@ -94,6 +104,15 @@ impl<const N: usize> Spectacle<N> {
         }
     }
 
+    /// add default sequence for any device implementing **adafruit neopixel BLE**
+    /// not specified in an other sequence.
+    ///
+    /// # Arguments
+    ///
+    /// * `runner`: sequence to stream
+    ///
+    /// returns: ()
+    ///
     pub fn add_default(&mut self, runner: DeviceSequence<N>) {
         let (tx, rx) = tokio::sync::watch::channel(Strip::<N>::new(PixelColor {
             red: 0,
@@ -104,6 +123,15 @@ impl<const N: usize> Spectacle<N> {
         self.default_receiver = Some(rx);
     }
 
+    /// Get channel associated with the mac address passed in parameters. If no channel found,
+    /// give back the default channel if existing.
+    ///
+    /// # Arguments
+    ///
+    /// * `mac_address`: mac address to look for
+    ///
+    /// returns: Option<Receiver<Strip<{ N }>>>
+    ///
     pub fn get_channel(&self, mac_address: &Address) -> Option<Receiver<Strip<N>>> {
         let channel = self.channels.get(mac_address);
         match channel {
@@ -124,6 +152,12 @@ impl<const N: usize> Spectacle<N> {
         }
     }
 
+    /// start to stream configured sequences. Returns the joinhandle of task to wait for
+    ///
+    ///
+    ///
+    /// returns: Vec<impl Future<Output = ()>>
+    ///
     pub fn run(&mut self) -> Vec<impl Future<Output = ()>> {
         let mut joinhandles = vec![];