diff --git a/chime/sensor.py b/chime/sensor.py
index 61d8408..e2d1f7d 100644
--- a/chime/sensor.py
+++ b/chime/sensor.py
@@ -38,10 +38,13 @@ class Reading:
     def __str__(self):
         return f'{self.time.strftime("%F %T %Z")},{self.time.timestamp()},{self.temp},{self.press},{self.hum}'
 
+    def timestamp(self):
+        return int(self.time.timestamp())
+
     def list(self):
         return [
             self.time.strftime("%F %T %Z"),
-            self.time.timestamp(),
+            self.timestamp(),
             self.temp,
             self.press,
             self.hum
@@ -68,7 +71,7 @@ class Reading:
 
     def json(self) -> bytes:
         return bytes(json.dumps({
-            'timestamp': self.time.timestamp(),
+            'timestamp': self.timestamp(),
             'temperature': self.temp,
             'pressure': self.press,
             'relative_humidity': self.hum,