Reed Switches and Reed sensors in Canal Hearing Aids
As widely known, Hearing Aids are devices designed to improve hearing by making sound audible to a person with hearing loss. Over the years, hearing aids have been getting smaller and smaller from behind-the-ear versions to in-the-ear versions called Canal Hearing Aids.
The behind-the-ear and in-the-ear versions were larger and had micro switches on the body that could be used to adjust the power on-off and volume levels. In the case of Canal Hearing Aids, the device itself is so tiny and fitted inside the ear canal, that remote operation is required. Such hearing aids use external wands to cycle the device through the various levels of volume.
Reed sensors have also shrunk a lot in size and aid themselves for use in such applications, and they also have other added benefits such as not requiring power of operation. A tiny reed sensor or a reed switch fitted inside helps sense the external “wand” or magnet which then signals the control circuit. The control circuit is programmed to switch the hearing aid between volume levels to power-off state each time the magnet is brought near the ear canal. Reed sensors are also very good at stably switching extremely low signal level currents reliably and are best suited for such hearing aids. An added bonus is that Reed Switches do not drain power from the battery when not in use.
Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.
The Reed Switches and Sensors used in such applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.
R5 Ultra-Miniature SMD Reed Sensor
|Omni polar, normally open (NO), 9.5 mm SMD pitch. 5W switching capability at 0.35...Continue reading|
R4 Ultra-miniature SMD Reed Sensor
|Omni polar, normally open (NO), 12.5 mm SMD pitch. 10W switching capability at 0.5...Continue reading|