What is the principle of hotel card accessing electricity?

Whether it's a hotel or a hotel, there is a small box the size of a switch at the door of every room, which says "Plug in the card to get electricity". But have you thought about it? Can we insert other cards besides the room card? What is the principle of this plug-in card to get electricity?

First, let's look at the power switch on the back of the card:

As can be seen from the three terminals, the working principle of this switch is to control the room power supply by controlling the on-off of the live wire.

At present, there are several induction forms for a large number of plug-in power switches on the market:

1. photoelectric type-the principle of this switch is to emit a beam of light inside the switch. When the light beam is blocked (plugged in), the internal electronic system will provide power by recognizing this signal. This switch has a disadvantage, that is, not only the room card, but anything that can block the light beam can be inserted into the switch to realize the power supply to the room. This kind of switch is gradually being eliminated and only exists in small hotels with old decoration and low price. Check-in staff can take advantage of this disadvantage, and insert small opaque cards, such as bank cards, ID cards and membership cards, which are similar in size to room cards, into the power switch, so that the room will still be electrified after leaving the room.

2.IC card type-an IC card identification device is installed inside the switch, and whether the room card is inserted is sensed by touching the metal chip on the room card. If the identification is correct, start power supply. This switch is improved on the basis of photoelectric switch. But it is not perfect. After a period of use, it is easy to cause the room card chip to fall off and the sensing device to malfunction. The later maintenance cost is high, and it is gradually eliminated. At first, it was widely used in chain hotels, hotels and so on.

3. Card frequency type-can be divided into low frequency card and high frequency card. Identify the frequency of the room card by switching the internal sensor, and judge whether the room card is correct. This card is very popular because of its smooth appearance and low maintenance cost. And you can customize your own hotel's exclusive frequency card to avoid the situation that the A hotel room card can get electricity from the B hotel, which is the most popular form of take-off switch identification in the market at present.

4. Dedicated-the principle is similar to the card frequency type, except that this card switch can not only read the card frequency, but also read the information of the room number in the card during the identification process. This kind of card is private, but it has many functions, complex internal structure and high cost. So it is generally used in more advanced hotels or office buildings.

Then, when the power switch identification card is successful, how to proceed to the next step? Inside the power switch, there is an integrated circuit board with a key component-micro relay, which controls the power supply. When the switch successfully identifies the card, it will automatically send a signal to the microswitch. After the microswitch is turned on, the relay coil is energized, and the relay is attracted to start power supply. After the card is pulled out, the microswitch is turned off, the contactor coil is powered off and the room is powered off.