This is the switch on the wall of hotels that only turns the power on to things like lighting and air conditioning while a guest is in the room. I was expecting this to actually sense an active card, but it's simpler than that, which also allows it to operate with a plain key identification card.
For some inexplicable reason I said LM324 (quad op amp) instead of LM358 (dual op amp) which I was thinking of. All the more impressive because I hardly ever use LM324s.
The modular approach to this design makes me wonder if there are other units that use the same power and relay base, but a different daughter board to implement other functions.
Although the instructions show the bezel and module as separate items, and mentions clipping the module into the frame, you can also just slide the front white plastic card holder up to remove it.
They win mega points for the main power PCB for robustness, electrical separation, and the decent relay. One slight twist could have been to shuffle the PCB and sandwich the thermal fuse between the relay's contact side and the MOV to add an extra layer of protection against burning contacts. The thermal fuse on the MOV transient suppressor is excellent. They tend to have an end of life failure mode of heating up, and a lot of products use them without allowing for that.
It would have been good to swap the positions of the power supply zener and decoupling capacitor to space the warm zener away from the electrolytic capacitor.
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For some inexplicable reason I said LM324 (quad op amp) instead of LM358 (dual op amp) which I was thinking of. All the more impressive because I hardly ever use LM324s.
The modular approach to this design makes me wonder if there are other units that use the same power and relay base, but a different daughter board to implement other functions.
Although the instructions show the bezel and module as separate items, and mentions clipping the module into the frame, you can also just slide the front white plastic card holder up to remove it.
They win mega points for the main power PCB for robustness, electrical separation, and the decent relay. One slight twist could have been to shuffle the PCB and sandwich the thermal fuse between the relay's contact side and the MOV to add an extra layer of protection against burning contacts. The thermal fuse on the MOV transient suppressor is excellent. They tend to have an end of life failure mode of heating up, and a lot of products use them without allowing for that.
It would have been good to swap the positions of the power supply zener and decoupling capacitor to space the warm zener away from the electrolytic capacitor.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Fascinating. I hadn’t realised about the off delay and assumed that they contained a microswitch mechanically activated by the card insertion or removal.
I’m stopping in a hotel at the moment, the cards with is identical apart from it works via rfid, if I put any card apart from the hotel one it doesn’t work. Also if you put the card against the reader it triggers the rfid and works
It has delay.
I remember some hotels, that have a slot for the key chain thingy with your room number on it.
Hello. If you stick in an old credit card or library card will it trick the system?
But I did visit London uk and that one can only be used with the keycards they give you(lucky they gave me and my family 4 cards)
i saw that in china and just stuck a standard card their and it works
I just mounted such card switches last week. But as a completely mechanical version. (Of course I took a closer look at them. It's just a "normal" push-button for the light installation, where only a mechanism is mounted on it that mechanically pretensions the push-button so that the thickness of the card is sufficient to actuate the push-button). It can also be operated with other cards without any problems. (e.g. identity card, driving licence, credit card, etc.).
How do they manage to heat shrink the 105 Deg C thermal fuse to the MOV without tripping the thermal fuse due to the heat of shrinking the heat shrink tubing?
I've never seen heat shrink that shrinks at below 105 deg C (the temperature of the thermal fuse).
Does anyone know how they do it?
K Watt.
So I don't see any security in this schematic so you could take any card like your own credit card and walk up to anybody's room and just walk into the room?
Never mind I heard you say it was just to turn on power inside of the hotel room I have never seen this and any hotel I've been in is this a UK thing
Very easy, and necessary, to defeat. I can't imagine these things are ever used properly. I have been known to leave my hotel TV on when I'm out because finding the one English news channel was such a palaver.
So this is a serious question. What would even be the need for something like this? I can understand for the door to get Into the room but once you are in the room why have to mess with a key card to turn on lights and stuff? Seems like a normal switch would just make more sense. I don't think hotels in the united States have anything like this for turning on lights in hotel rooms. Seems odd to me.