py: add battery voltage to debug overlay

python_payload/st3m/run.py

@@ -75,6 +75,7 @@ def _make_compositor(reactor: Reactor, vm: ViewManager) -> overlays.Compositor:
     # Configure debug overlay fragments.
     debug = overlays.OverlayDebug()
     debug.add_fragment(overlays.DebugReactorStats(reactor))
+    debug.add_fragment(overlays.DebugBattery())
     compositor.add_overlay(debug)
 
     debug_touch = overlays.OverlayCaptouch()

python_payload/st3m/ui/elements/overlays.py

@@ -10,6 +10,7 @@ from st3m import Responder, InputState, Reactor
 from st3m.goose import Dict, Enum, List, ABCBase, abstractmethod, Optional
 from st3m.utils import tau
 from st3m.ui.view import ViewManager
+from st3m.input import power
 from ctx import Context
 
 import math
@@ -122,6 +123,17 @@ class DebugReactorStats(DebugFragment):
         return " ".join(res)
 
 
+class DebugBattery(DebugFragment):
+    """
+    DebugFragment which provides the OverlayDebug with information about the
+    battery voltage.
+    """
+
+    def text(self) -> str:
+        v = power.battery_voltage
+        return f"bat: {v:.2f}V"
+
+
 class OverlayDebug(Overlay):
     """
     Overlay which renders a text bar at the bottom of the screen with random