diff --git a/esphomeyaml/components/sensor/pulse_counter.rst b/esphomeyaml/components/sensor/pulse_counter.rst
index a16a83306..18c1cf0c8 100644
--- a/esphomeyaml/components/sensor/pulse_counter.rst
+++ b/esphomeyaml/components/sensor/pulse_counter.rst
@@ -42,6 +42,8 @@ Configuration variables:
 - **internal_filter** (*Optional*, :ref:`config-time`): If a pulse shorter than this
   time is detected, it’s discarded and no pulse is counted. Defaults to ``13us``. On the ESP32,
   this value can not be higher than ``13us``, for the ESP8266 you can use larger intervals too.
+  If you enable this, set up the ``count_mode`` to increase on the falling edge, not leading edge.
+
 - **update_interval** (*Optional*, :ref:`config-time`): The interval to check the sensor. Defaults to ``60s``.
 
 - **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.