diff --git a/sense_morse.py b/sense_morse.py
index 7854b90..fe2d5b8 100644
--- a/sense_morse.py
+++ b/sense_morse.py
@@ -32,6 +32,10 @@ END_WORD = '       '
 
 class MorseSenseHatKeyer:
 
+    green = [0, 255, 0]
+    yellow = [255, 255, 0]
+    red = [255, 0, 0]
+
     def __init__(self):
         self.sense = SenseHat()
         self.sense.stick.direction_up = self.pushed_up
@@ -49,66 +53,86 @@ class MorseSenseHatKeyer:
             self.current_morse_char = ''
 
     def pushed_right(self, event):
-        """ validation """
+        """ validation : caractère, mot, message """
         # selon le cas : validation de la lettre, du mot etc
         if event.action != ACTION_RELEASED:
             if self.current_morse_char == '': # pas de lettre en cours, validation du mot, et affichage
                 self.sense.show_message(self.message_ascii)
             elif self.current_morse_char != '': # validation de la lettre
-                self.message_ascii += morse_talk.decode(self.current_morse_char)
-                self.current_morse_char = ''
+                self.validate_char()
 
     def pushed_down(self, event):
         """ ajout trait """
-        if event.action != ACTION_RELEASED:
+        if event.action == ACTION_HELD:
             self.show_dash()
-            self.current_morse_char += '-'
-            self.show_char()
+        if event.action == ACTION_RELEASED:
+            self.add_dash()
 
     def pushed_up(self, event):
         """ ajout point """
-        if event.action != ACTION_RELEASED:
+        if event.action == ACTION_HELD:
             self.show_dot()
-            self.current_morse_char += '.'
-            self.show_char()
+        if event.action == ACTION_RELEASED:
+            self.add_dot()
 
 
-    def show_dot(self, duration=0.1):
+    def show_dot(self, rgb=None):
+        rgb = rgb or [150, 150, 150]
         self.sense.clear()
         for x in range(3, 5):
             for y in range(3, 5):
-                self.sense.set_pixel(x, y, 255, 255, 255)
-        time.sleep(duration)
+                self.sense.set_pixel(x, y, rgb)
+        # time.sleep(duration)
 
-    def show_dash(self, duration=0.1):
+    def show_dash(self, rgb=None):
+        rgb = rgb or [150, 150, 150]
         self.sense.clear()
         for x in range(1, 7):
             for y in range(3, 5):
-                self.sense.set_pixel(x, y, 255, 255, 255)
-        time.sleep(duration)
+                self.sense.set_pixel(x, y, rgb)
+        # time.sleep(duration)
 
     def refresh(self, event):
         pass
         # self.sense.clear()
 
-    def show_char(self):
-        char = morse_talk.decode(self.current_morse_char)
+    def show_char(self, char, rgb=None):
+        """ affiche un caractère """
+        rgb = rgb or [150, 150, 150]
         self.sense.clear()
-        self.sense.show_letter(char)
+        self.sense.show_letter(char, rgb)
 
     def add_dot(self):
-        pass
+        """ ajout d'un point au caractère courant """
+        try:
+            self.current_morse_char += '.'
+            char = morse_talk.decode(self.current_morse_char)
+            self.show_char(char, self.yellow)
+        except KeyError as err: # l'ajout ne donne pas un caractère interprétable
+            self.show_char('X', self.red)
+            self.current_morse_char = ''
 
     def add_dash(self):
-        pass
+        """ ajout d'un trait au caractère courant """
+        self.current_morse_char += '-'
+        try:
+            char = morse_talk.decode(self.current_morse_char)
+            self.show_char(char, self.yellow)
+        except KeyError as err: # l'ajout ne donne pas un caractère interprétable
+            self.show_char('X', self.red)
+            self.current_morse_char = ''
+
 
     def reset_char(self):
         """ annule le caractère courant """
         pass
 
     def validate_char(self):
-        """ valide la lettre et ajoute un espace """
-        pass
+        """ valide la lettre courante """
+        char = morse_talk.decode(self.current_morse_char)
+        self.show_char(char, self.green)
+        self.message_ascii += char
+        self.current_morse_char = ''
 
     def show_message(self):
         """ affiche le message courant """
@@ -117,10 +141,10 @@ class MorseSenseHatKeyer:
 if __name__ == "__main__":
     try:
         keyer = MorseSenseHatKeyer()
-        keyer.sense.show_message("morse://")
+        keyer.sense.show_message("morse://", 0.02)
         # waiting for jostick events and directing them to keyer
         pause()
     except (KeyboardInterrupt, SystemExit) as err:
         sense = SenseHat()
-        sense.show_message('out')
+        sense.show_message('out', 0.02)
         sense.clear()