diff --git a/pico-dashboard/hardware/buzzer.py b/pico-dashboard/hardware/buzzer.py
index e69de29..936c227 100644
--- a/pico-dashboard/hardware/buzzer.py
+++ b/pico-dashboard/hardware/buzzer.py
@@ -0,0 +1,26 @@
+class Buzzer:
+    def __init__(self, pin=None):
+        self.pin = pin
+        self.enabled = False
+        self.pattern = None
+
+    def on(self):
+        self.enabled = True
+        if self.pin:
+            self.pin.value(1)
+
+    def off(self):
+        self.enabled = False
+        self.pattern = None
+        if self.pin:
+            self.pin.value(0)
+
+    def set_pattern(self, pattern):
+        self.pattern = pattern
+        self.enabled = pattern is not None
+
+    def update_from_alarm_view(self, alarm_view):
+        if alarm_view.should_buzz():
+            self.set_pattern("critical")
+        else:
+            self.off()
diff --git a/tests/test_pico_core.py b/tests/test_pico_core.py
index 72d4195..26b1ea4 100644
--- a/tests/test_pico_core.py
+++ b/tests/test_pico_core.py
@@ -628,3 +628,43 @@ def test_alarm_view_model_sensor_failure():
     assert alarm["severity"] == "warning"
     assert alarm["title"] == "Sensor Failure"
     assert alarm["detail"] == "Outside"
+
+
+class FakePin:
+    def __init__(self):
+        self.values = []
+
+    def value(self, value):
+        self.values.append(value)
+
+
+def test_buzzer_on_off():
+    from hardware.buzzer import Buzzer
+
+    pin = FakePin()
+    buzzer = Buzzer(pin)
+
+    buzzer.on()
+    assert buzzer.enabled is True
+    assert pin.values[-1] == 1
+
+    buzzer.off()
+    assert buzzer.enabled is False
+    assert pin.values[-1] == 0
+
+
+def test_buzzer_updates_from_alarm_view():
+    from hardware.buzzer import Buzzer
+    from ui.alarm_view_model import AlarmViewModel
+
+    buzzer = Buzzer()
+
+    buzzer.update_from_alarm_view(AlarmViewModel(["fridge_zone_1_high"]))
+
+    assert buzzer.enabled is True
+    assert buzzer.pattern == "critical"
+
+    buzzer.update_from_alarm_view(AlarmViewModel([]))
+
+    assert buzzer.enabled is False
+    assert buzzer.pattern is None