Add an example for the Threshold binary sensor (#15073)

Co-authored-by: Franck Nijhof <git@frenck.dev>

source/_integrations/threshold.markdown

@@ -60,3 +60,24 @@ name:
   type: string
   default: Threshold
 {% endconfiguration %}
+
+## Examples
+
+### Is the temperature rising or falling
+
+The hysteresis parameter can be used in this use-case to avoid frequent state changes around the maximum or the minimum of a temperature curve. We also have to utilize the [derivative sensor](/integrations/derivative/) for this use-case:
+
+```yaml
+sensor:  
+  - platform: derivative # will be positive for rising temperatures and negative for falling temperatures
+    source: sensor.temperature
+    unit_time: min
+    name: temperature derivative
+    time_window: 00:05:00
+binary_sensor:
+  - platform: threshold # will switch state not at 0°C/min but 0.1°C/min or -0.1°C/min depending on the current state of the sensor, respectively
+    entity_id: sensor.temperature_derivative
+    upper: 0
+    hysteresis: 0.1 # sensor 
+    name: temperature rising
+```