Mathew Laibowitz, Joseph A. Paradiso

Abstract

Not too long ago, incorporating a wireless RF link into an electronics project implied mastery of the mysteries of RF electronics and layout or the need to incorporate often a fairly cumbersome subsystem into your design. This has all changed enormously over the past few years, with the introduction of embedded modules that encapsulate the radio’s electronics onto a compact device, which can easily be mounted onto a small part of your project’s circuit card. The embedded RF arena is now exploding with development of new products – although many small hybrid transmitter, receiver, and transceiver modules are on the market, the latest entries include totally integrated RFIC’s that put the radio on a CMOS chip with a microcontroller, in some cases adorned with peripherals such as ADC’s, DAC’s, timers, etc. These elements are intrinsically interconnected, with signal strength, transmit frequency, and other radio parameters digitally accessible as processor registers, and protocols available as subroutines or resident in the device’s firmware. Although one still needs to be mindful of proper antenna matching, appropriate bypassing, zero-balancing, interference issues, etc., incorporating radio links into projects has never been simpler. In this article, we present a quick snapshot of the state-of-the-art in embedded RF devices, then discuss an application that we have built around one of them in a wearable badge platform to facilitate social interaction in large events. We conclude by briefly mentioning how we use embedded RF in a dense wearable sensor platform, and point to RFIC’s built around heavier protocols, such as Bluetooth [1] and ZigBee [2].