Module Features :
1, imported normally open reed
2 , the comparator output signal is clean, good waveform , driving ability , more than 15mA.
3, the working voltage of 3.3V-5V
4, the output format : digital switching outputs ( 0 and 1 )
5 , a fixed bolt holes for easy installation
6, small PCB board size : 3.2cm x 1.4cm
7 , using a wide voltage LM393 comparator
Reed is a dry reed pipe for short, is a kind of passive electronic switching element contacts , with a simple structure , small size easy to control , etc., which is generally a sealed enclosure glass tube are installed there are two elastic spring plate of iron , also called rhodium metal filling with inert gas . Normally, the two reed glass tube made of special materials are separated . When a magnetic substance near the glass tube under the action of the magnetic field lines of the two reed tube is magnetized to attract each other in contact spring will pull together to make a circuit node connected to the communication . External magnetic disappear after two reeds are separated because of their flexibility , the line also disconnected. Therefore, as a signal to control the use of a magnetic field line switching devices , reed can be used as a sensor for counting , limit , etc. ( in the security system is mainly used for door sensor , magnetic window production ) , but also is widely used in a variety of communications devices. In practice, this is usually controlled by the permanent magnet is turned on or not two pieces of metal , it is also called " magnetron ."
Module for use:
1 Reed needs the use of magnets in magnetic induction to a certain time, will create a conductive state , the module output low, when there is no magnetic force , was disconnected state , the output high , reed and sensing distance beyond the magnet within 1.5cm of insensitivity or may no trigger phenomenon ;
2 module DO output can be MCU I / O port is directly connected through the microcontroller can detect dry reed pipe trigger state ;
3 output and relay module DO IN terminal connected to form high-power reed switches, high voltage direct control .