Monitoring Door using Reed Switch:
Monitoring the door quite simply works done with the help of Magnetic Reed Switch. This used to check whether the door closed or opened. Based on the status about the door, we can make an alarm, send a message to the user or people, storing the data about the home in the cloud etc. These are the daily life applications of Reed switch. This might seem to be a simple one, but if we add some more sensors along with it, we can use this in a Home security system, Burglar Alarm, calculating the speed of cycle, etc.,
A magnetic contact switch is basically a reed switch encased in a plastic shell so that we can easily apply them in a door, a window or a drawer to detect if the door is open or closed.
When the Reed switch kept near to Magnet, the magnetic material inside the reed switch pull together and switch closes. When there is no magnetic field, then ferrous materials separate and switch open. By the way, this element reacts as a non-contact switch on a circuit, and also it can carry up to 1.2A current. Reed switches data continuously monitored by the Arduino. If there are any changes, the Arduino will immediately react to the change.
Reed Switch is an Electric switch impact by Magnetic field. Inside the Reed switch, there will be a contact made up of Ferrous Material.
The reed switch contains a pair (or more) of magnetizable, flexible, metal reeds whose end portions separated by a small gap when the switch open. The reeds hermetically sealed in opposite ends of a tubular glass envelope.
A magnetic field (from an electromagnet or a permanent magnet) will cause the reeds to attract each other, thus completing an electric circuit. The spring force of the reeds causes them to separate, and open the circuit when the magnetic field ceases. Another configuration contains a non-ferromagnetic normally-closed contact that opens when the ferromagnetic normally-open contact closes.
A thin layer of non-ferromagnetic material applied to the reed switch contact area to serve as an electrical contact switching (wear) surface and, for normally-open contacts, as a magnetic spacer whose thickness is important in controlling the magnetic field level at which the contact opens (the drop-out). Reed switch contacts are typically Rh, Ru, Ir, or W. The other versions of reed switches is Mercury “Wetted” contacts. Such switches must mount in a particular orientation. Otherwise, drops of mercury may bridge the contacts even when not activated.
Since the contacts of this switch sealed away from the atmosphere, they protected against atmospheric corrosion. The hermetic sealing of a reed switch makes them suitable for use in explosive atmospheres where tiny sparks from conventional switches would constitute a hazard.