Reed sensors in Survival rafts and ELTs
Survival rafts contain water sensors which trigger the compressed air cylinder to inflate the raft when dropped into the sea or a lake or a river. To prevent against accidental inflation, a reed switch is placed in the control circuit of the raft which is activated with a magnet on the outside of the case.
Before the raft can be used, it needs to be taken out of the case which then takes the magnet away from the reed switch. This activates the water sensor and the homing beacon. Reed Switches are also used in emergency locator transmitters (ELT) to prevent the unit from transmitting when inside the cover. This is also achieved in a similar manner, by placing a magnet inside the pocket of the cover and mounting a reed switch inside the ELT. This keeps the ELT from transmitting as long as it is inside its cover. Such applications use normally open or normally closed type reed switches depending on the control circuit logic.
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.
R2B, Normally Closed, SMD Reed Sensor
|Polarity Sensitive, Normally Closed (NC), 19.5 mm SMD and low-profile SMD pitch. 10W switching...Continue reading|
MS-106 Reduced Miniature PCB Mountable Reed Sensor
|Omni polar, normally open (NO), epoxy encapsulated, 15.2 mm PCB mountable pin pitch, capable...Continue reading|
MS-108 Standard Size PCB Mountable Reed Sensor
|Omni polar, normally open (NO), epoxy encapsulated, 17.7 mm PCB mountable pin pitch, capable...Continue reading|