Company: Technology Trends

Hidden Sensors - Embedded Designs Are Watching You

The design is watching you; not the designer. New technologies (interfaces and sensors) are showing up in widgets where we might not even realize it. Sensors are being designed into products to detect a user's presence and motion to make the products more responsive to the user. Camera-based solutions like the Microsoft Kinect are incredibly intelligent but at $249 it's not cost effective for an embedded design. The good news is that emerging interfaces are becoming more practical to add to embedded designs because for as low as a few dollars or less, designers can add sensing capabilities to their products.

The cost effective innovations that enable sensing proximity or motion are:

  • Capacitive proximity detection
  • Infrared and ambient-light sensors
  • Dual-core gyroscopes

We will review each of these sensing capabilities in the TRENDS Indesign newsletter starting with Capacitive Proximity Detection in this edition.

Capacitive Proximity

Touchscreen smartphones and tablets are what really made capacitive sensing popular. The popularity of capacitive touch has enabled production costs to drop as well as but has also enabled proximity sensing in addition to traditional touch and gestures. Proximity sensing allows systems to become more intelligent and determine if a touch was intended or not (i.e. if a user grabs a device to hold it but touches the edges of the screen). Proximity sensing also enables battery powered systems to keep a system in a deeper sleep state and then wake up just before a user makes contact. This can be critical for designs that require a system to have long battery life.

Capacitive proximity sensing requires few or no additional components for systems that already have capacitive touch capabilities. Freescale MPR121, Atmel QTouch (AT42QT2120), Cypress CY8C21434, and Semtech SX8636 are a few solution options that support distances up to ~ 1 foot.

Keep an eye out for the next TRENDS Indesign when we will discuss Infrared Proximity.