diff --git a/readme.md b/readme.md
index 9596432..786db2e 100644
--- a/readme.md
+++ b/readme.md
@@ -1962,7 +1962,9 @@ UK 13A sockets at the moment.
 ## Microswitches
 Used for limit switches. Currently only the button type is supported as the lever and roller types are less accurate.
 
-The switch is drawn with the button at the nominal operation point. This can be plus or minus `microswitch_op_tol(type)`.
+The origin of the switch is in the center of the body. `microswitch_button_pos()` is the offset to tip of the button at its operating point.
+
+The switch is drawn with the button at the nominal operation point. This actual trigger point can be plus or minus `microswitch_op_tol(type)`.
 
 When the button is released it comes out by a maximum of `microswitch_fp_max(type)` from the nominal operating point.
 
diff --git a/vitamins/microswitch.scad b/vitamins/microswitch.scad
index af6b131..28059ef 100644
--- a/vitamins/microswitch.scad
+++ b/vitamins/microswitch.scad
@@ -20,7 +20,9 @@
 //
 //! Used for limit switches. Currently only the button type is supported as the lever and roller types are less accurate.
 //!
-//! The switch is drawn with the button at the nominal operation point. This can be plus or minus `microswitch_op_tol(type)`.
+//! The origin of the switch is in the center of the body. `microswitch_button_pos()` is the offset to tip of the button at its operating point.
+//!
+//! The switch is drawn with the button at the nominal operation point. This actual trigger point can be plus or minus `microswitch_op_tol(type)`.
 //!
 //! When the button is released it comes out by a maximum of `microswitch_fp_max(type)` from the nominal operating point.
 //