Determining Hover Distance of an Active Stylus

Abstract

In one embodiment, a change in capacitance at one or more capacitive nodes of a touch sensor of a device is detected. The change in capacitance is detected in response to a stylus being in proximity with but not touching the touch sensor. The stylus includes one or more computer-readable media embodying logic and one or more electrodes for effecting charge transfer wirelessly in the device through the touch sensor of the device. The change in capacitance is analyzed to determine a distance between the stylus and the device.

What is claimed is: 
     
         1 . A method comprising:
 detecting a change in capacitance at one or more capacitive nodes of a touch sensor of a device in response to a stylus being in proximity with but not touching the touch sensor, the stylus comprising one or more computer-readable media embodying logic and one or more electrodes for effecting charge transfer wirelessly in the device through the touch sensor of the device; and   analyzing the change in capacitance to determine a distance between the stylus and the device.   
     
     
         2 . The method of  claim 1 , wherein the electrodes are located in a tip of the stylus. 
     
     
         3 . The method of  claim 1 , wherein the device detects the change in capacitance at the one or more capacitive nodes of the touch sensor and analyzes the change in capacitance to determine the distance between the stylus and the device. 
     
     
         4 . The method of  claim 2 , wherein the stylus detects the change in capacitance at the stylus electrodes and analyzes the change in capacitance to determine the distance between the stylus and the device. 
     
     
         5 . The method of  claim 1 , wherein analyzing the change in capacitance comprises analyzing a magnitude of the change in capacitance. 
     
     
         6 . The method of  claim 1 , wherein analyzing the change in capacitance comprises analyzing the change in capacitance in each of the one or more capacitive nodes of the touch sensor. 
     
     
         7 . The method of  claim 1 , wherein the distance between the stylus and the device is measured between one or more of the electrodes of the stylus and the touch sensor. 
     
     
         8 . One or more computer-readable non-transitory storage media embodying logic that is operable when executed to:
 detect a change in capacitance at one or more capacitive nodes of a touch sensor of a device in response to a stylus being in proximity with but not touching the touch sensor, the stylus comprising one or more electrodes for effecting charge transfer wirelessly in the device through the touch sensor of the device; and   analyze the change in capacitance to determine a distance between the stylus and the device.   
     
     
         9 . The media of  claim 8 , wherein the electrodes are located in a tip of the stylus. 
     
     
         10 . The media of  claim 8 , wherein the logic is located at the device. 
     
     
         11 . The media of  claim 9 , wherein the stylus further comprises one or more computer-readable non-transitory storage media embodying logic that is operable when executed to detect a change in capacitance at the stylus electrodes and analyze the change in capacitance to determine the distance between the stylus and the device. 
     
     
         12 . The media of  claim 8 , wherein analyzing the change in capacitance comprises analyzing a magnitude of the change in capacitance. 
     
     
         13 . The media of  claim 8 , wherein analyzing the change in capacitance comprises analyzing the change in capacitance in each of the one or more capacitive nodes of the touch sensor. 
     
     
         14 . The media of  claim 8 , wherein the distance between the stylus and the device is measured between one or more of the electrodes of the stylus and the touch sensor. 
     
     
         15 . A device comprising:
 a touch sensor comprising one or more capacitive nodes; and   one or more computer-readable non-transitory storage media embodying logic that is operable when executed to:
 detect a change in capacitance at a capacitive node in response to a stylus being in proximity with but not touching the touch sensor, the stylus comprising one or more electrodes for effecting charge transfer wirelessly in the device through the touch sensor of the device; and 
 analyze the change in capacitance to determine a distance between the stylus and the device. 
   
     
     
         16 . The device of  claim 15 , wherein the electrodes are located in a tip of the stylus. 
     
     
         17 . The device of  claim 16 , wherein the stylus further comprises one or more computer-readable non-transitory storage media embodying logic that is operable when executed to detect a change in capacitance at the stylus electrodes and analyze the change in capacitance to determine the distance between the stylus and the device. 
     
     
         18 . The device of  claim 15 , wherein analyzing the change in capacitance comprises analyzing a magnitude of the change in capacitance. 
     
     
         19 . The device of  claim 15 , wherein analyzing the change in capacitance comprises analyzing the change in capacitance in each of the one or more capacitive nodes of the touch sensor. 
     
     
         20 . The device of  claim 15 , wherein the distance between the stylus and the device is measured between one or more of the electrodes of the stylus and the touch sensor.