app: Implement volume curve

software/src/app.py

@@ -9,6 +9,9 @@ from utils import TimerManager
 
 Dependencies = namedtuple('Dependencies', ('mp3player', 'nfcreader', 'buttons'))
 
+# Should be ~ 6dB steps
+VOLUME_CURVE = [1, 2, 4, 8, 16, 32, 63, 126, 251]
+
 
 class PlayerApp:
     def __init__(self, deps: Dependencies):
@@ -18,6 +21,8 @@ class PlayerApp:
         self.player = deps.mp3player(self)
         self.nfc = deps.nfcreader(self)
         self.buttons = deps.buttons(self) if deps.buttons is not None else None
+        self.volume_pos = 3
+        self.player.set_volume(VOLUME_CURVE[self.volume_pos])
 
     def onTagChange(self, new_tag):
         if new_tag is not None:
@@ -50,8 +55,10 @@ class PlayerApp:
 
     def onButtonPressed(self, what):
         if what == self.buttons.VOLUP:
-            self.player.set_volume(min(255, self.player.get_volume()+1))
+            self.volume_pos = min(self.volume_pos + 1, len(VOLUME_CURVE) - 1)
+            self.player.set_volume(VOLUME_CURVE[self.volume_pos])
         elif what == self.buttons.VOLDOWN:
-            self.player.set_volume(max(0, self.player.get_volume()-1))
+            self.volume_pos = max(self.volume_pos - 1, 0)
+            self.player.set_volume(VOLUME_CURVE[self.volume_pos])
         elif what == self.buttons.NEXT:
             self.player.play_next()