diff --git a/Tools/px4moduledoc/srcparser.py b/Tools/px4moduledoc/srcparser.py
index c1ef753755..258ba0bfa4 100644
--- a/Tools/px4moduledoc/srcparser.py
+++ b/Tools/px4moduledoc/srcparser.py
@@ -16,7 +16,7 @@ class ModuleDocumentation(object):
     valid_categories = ['driver', 'estimator', 'controller', 'system',
                         'communication', 'command', 'template', 'simulation', 'autotune']
     valid_subcategories = ['', 'distance_sensor', 'imu', 'airspeed_sensor',
-                           'magnetometer', 'baro', 'optical_flow']
+                           'magnetometer', 'baro', 'optical_flow', 'rpm_sensor']
 
     max_line_length = 80 # wrap lines that are longer than this