US 12,676,612 B2 · IR timing calibration for a key switch

Abstract

A keyboard system comprises a key structure including a key switch with a lighting element and phototransistor, and one or more processors that drive the lighting element for a first pulse duration. The output of the phototransistor is determined at the end of the first pulse duration, wherein the key structure is determined to be pressed when the output is below a first output value at an end of the first pulse duration, and unpressed when the output of the phototransistor is above a second output value at the end of the first pulse duration. A fall-time of the output during the first pulse duration is determined and the first pulse duration is calibrated to a second pulse duration when the fall time less than the first pulse duration, the second pulse duration being greater than the fall time and less than the first pulse duration.

Claims16

Dependent claims

A keyboard system comprising:

a key structure including a key switch comprised of:
a lighting element;
and
a phototransistor;
one or more processors communicatively coupled to the key switch, the one or more processors configured to:
drive the lighting element for a first pulse duration;
determine an output of the phototransistor at an end of the first pulse duration;
determine a press state of the key structure based at least in part on an output value of the output of the phototransistor at the end of the first pulse duration;
determine a fall-time of the output of the phototransistor during the first pulse duration;
and
calibrate the first pulse duration to a second pulse duration when the fall-time of the output of the phototransistor is less than the first pulse duration, wherein the second pulse duration is greater than the fall-time and less than the first pulse duration.

8 more elements

Dependencies are inferred from the claim text.

IR timing calibration for a key switch

Life of this patent

IR timing calibration for a key switch

Life of this patent

Abstract

Claims16