Human-machine interaction has evolved significantly over the past decade through enhancements in user interfaces and smart design. Many of these changes have focused around touchscreen interfaces with high-precision, low-power capacitive touchscreens at the forefront particularly in the handset market. Now, through advancements in human interface (HI) technology and design, infrared proximity sensors are poised to usher in the next user interface innovations centered on touchless gesturing.
Traditionally, infrared proximity sensing systems have incorporated legacy photo-detectors and photo-interrupters, which trigger based on motion or interruption respectively. These proximity sensing solutions are used extensively in automatic doors and lavatory dispensing systems, but the applications have been limited due to the sensor size, power and configurability. More advanced active proximity sensors offer exciting features and promise enhancements to consumer electronics and industrial products.
Next-generation infrared sensor offerings, such as the Silicon Labs Si114x product family, are not only smaller and lower power than previous offerings, but also have the ability to drive multiple infrared light emitting diodes (LEDs), thereby enabling advanced gesture inputs in multiple dimensions.
Evolution from single- to multi-LED systems
Single-LED driver proximity sensors have been used in touchscreen handsets for many years and represent the highest-volume proximity sensor market, but their use has not been without issues. For example, although proximity sensors are used to deactivate handset touchscreens during calls to eliminate errant touches by the cheek, a quick web search reveals that many end-users are unhappy with proximity-sensor performance in their handsets. Accidentally muting calls, initiating conference calls and hanging up on callers are frequent mishaps caused by erroneous proximity sensor operation.
Why does a seemingly simple proximity-sensing system malfunction so frequently? The answer lies in the sensor design and configurability as well as the mechanical guidelines that accompany them. Many infrared proximity sensors are just that: dumb sensors that output raw data based on the signals received. The sensors do not have any onboard smarts to aid in