From a3271f0522d24b21264456e1a0d47aece608283b Mon Sep 17 00:00:00 2001
From: Fabio Manganiello <blacklight86@gmail.com>
Date: Thu, 1 Aug 2019 23:33:36 +0200
Subject: [PATCH] Only return the sensor data whose value has changed on the
 envirophat backend

---
 platypush/backend/sensor/envirophat.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/platypush/backend/sensor/envirophat.py b/platypush/backend/sensor/envirophat.py
index 03f9cbc5..2d7711ab 100644
--- a/platypush/backend/sensor/envirophat.py
+++ b/platypush/backend/sensor/envirophat.py
@@ -27,6 +27,7 @@ class SensorEnvirophatBackend(SensorBackend):
         super().__init__(self, **kwargs)
 
         self.qnh = qnh
+        self._last_read = {}
         self.enabled_sensors = {
             'temperature': temperature,
             'pressure': pressure,
@@ -43,9 +44,10 @@ class SensorEnvirophatBackend(SensorBackend):
         ret = {
             sensor: sensors[sensor]
             for sensor, enabled in self.enabled_sensors.items()
-            if enabled and sensor in sensors
+            if enabled and sensor in sensors and sensors[sensor] != self._last_read.get(sensor)
         }
 
+        self._last_read = ret
         return ret