diff --git a/msg/sensor_accel.msg b/msg/sensor_accel.msg
index 9dcefa6b87..d6d957cb8f 100644
--- a/msg/sensor_accel.msg
+++ b/msg/sensor_accel.msg
@@ -15,4 +15,4 @@ int16 y_raw
 int16 z_raw
 int16 temperature_raw
 
-uint32 device_id
+uint32 device_id	# unique device ID for the sensor that does not change between power cycles
diff --git a/msg/sensor_gyro.msg b/msg/sensor_gyro.msg
index 31636d148a..8b0b72f12d 100644
--- a/msg/sensor_gyro.msg
+++ b/msg/sensor_gyro.msg
@@ -15,4 +15,4 @@ int16 y_raw
 int16 z_raw
 int16 temperature_raw
 
-uint32 device_id
+uint32 device_id	# unique device ID for the sensor that does not change between power cycles