A BETTER WAY TO GO WIRELESS
James Anderson · The Hearing Journal · 2008
Although I enjoyed your November 2007 special issue on wireless technology, people tend to forget that hearing aid batteries typically supply only a thousandth of a watt of power, most of which is used to create acou-stic waves rather than radio waves. Even the planned low-power version of Bluetooth will consume more than 20 times this amount. As a result, some hearing aid manufacturers have developed wireless links that consume less than a millionth of a watt. Unfortunately, such links typically are unable to handle multiple users in close proximity, and may be susceptible to interference from nearby machinery and even solar activity. Recent advances in RFID (radio frequency identification) technology, however, hold promise for hearing aid applications. In an RFID system, battery-free computers operate from power that is wirelessly beamed to them by an external source, and the same wireless link is also used to transmit bi-directional data. Over a decade ago, such equipment used the microwave band now occupied by Bluetooth (see U.S. Pat. No. 5,721,783 and SCS's Dura-label), but it was expensive at the time. Since 2003, low-cost RFID systems operating at 13.56 MHz, known as near-field communication, have been developed that provide data rates of nearly a half-million bits per second. Because these signals pass safely through the human body, this approach presently holds the most promise for practical and cost-effective wireless hearing aid systems. James Anderson, PhD Inventor, Islington, MA