Wireless door opener - Page 1
Forum section: electronics / projects

author: PinheadBE
author_rank: Regular Contributor
timestamp: March 10, 2015, 11:09:31 am
content: Hi there,My mother suffers from disability and is not able to open the main door of her building with a key.Fortunately, that door is also equipped with an electric opener so that the residents can open the main door to visitors, as in any building I know of.Therefore, I installed a simple RC relay which emulates the press on the openenr switch present on her interphone device from inside her apartment.That was very easy because this old system was purely analog. So the contacts of my relay were just screwed on the right wires for the opener switch on the interphone and it worked like a charm for years.But now, the whole interphone system in the building has been replaced by a digital system on a 2 wire bus.The unit inside her apartment is a Aiphone GT-1D v2.There is, of course, a simple push button to actuate the door opener on the unit, but, as read in the user manual, the unit must be in conversation with the main unit in the entrance hall for this button to work.So, my guess to solder two wires on the push-button on the PCB to be closed by the RC relay will not work anymore.First, I am trying to find a schematic of the GT-1D unit (without success until now). It would help me to understand how that bl**dy thing works.Then, I am also in search of any information on the alternatives I could have to install my RC relay on her unit, with the limitaiton that I cannot (and will not) do any modification to the main panel in the entrance hall.I suspect I would have to emulate an actuation on the switch detecting that the phone is off-hook, and then, switch the door opener PB, but I'm not sure this would be enough...Any help and/or information would be welcome.Thanks a lot.

author: Fred27
author_rank: Unknown
timestamp: March 10, 2015, 11:37:01 am
content: It sounds like the relay would still work if the unit "is in conversation with the main unit". How is this achieved? Would she have to just ring the bell for her apartment (to start the conversation) and then use the relay?Also, have you tried asking the manufacturer. If you explain why you want to do this then they might be helpful.

author: Muttley Snickers
author_rank: Unknown
timestamp: March 10, 2015, 12:17:24 pm
content: This is an easy fix, simply notify the building/ property managers of your mothers difficulty, hacking into or potentially compromising the security of other residents in addition to your family is completely out of order.PS: I install these systems and have done so for over 25 years, so you should really leave it alone.

author: kolbep
author_rank: Frequent Contributor
timestamp: March 10, 2015, 01:22:29 pm
content: You might need 2 relays,One that Mimics the hookswitch,and then about a second later the 2nd one operates mimicing the press switchBut I do agree about the security aspects

author: PinheadBE
author_rank: Regular Contributor
timestamp: March 11, 2015, 09:09:33 am
content: For the security aspect, don't worry: this is not a cheap 2 $US system ...but more sort of 32-bit code (4 billion possibilities....).It's more easy to duplicate a stolen/borrowed key than find out the right combination.Or even simply force the keyslot with a simple screwdriver (door is not shielded...) . I am even pretty sure that a signle 9V battery could be sufficient, since the wires going to the electric opener are accessible from the entrance hall.And of course, an installator (or salesman) would tell me to not try to do it by myself.... because they sell an even less secured solution (8-bit coded RC) for almost 800 EUR (including installation).No thanks.So back to square one:The two relay option (first the off-hook switch, then the door opener switch) was indeed one of my guesses, but i am still not sure this would be sufficient, because there could be some sort of protocol that needs first that a call be initiated from the main entrance hall panel by pressing the bell switch..So the scheme would be:- Call an apartment (bell switch in entrance hall)- apartment takes the set off-hook (and now, the communication is settled between units),- apartment presses the opener buttonTo be sure of that, I'd need more technical documentation that what is available ....Thanks again

author: Muttley Snickers
author_rank: Unknown
timestamp: March 11, 2015, 09:46:03 am
content: Well Pinhead if you were in Australia doing this not only would you get a big kick in the ass but you would probably get a knock on your door from the relevant authority. Over here you must be a registered installer or licenced technician to work on or install within reason any security system or device.Regardless of the quality of your RF devices if your relay latches then the door will remain unlocked. On a technical level the door would generally be released by a contact either in the front door station otherwise by the Bus Controller, also the system may be configured to permit code entry at the front door station for emergency services, etc.Your double relay solution could potentially render the entire system offline and it would be rather difficult for the installer to trace and diagnose the problem should it arise. I've said my peace, I understand your problem and am sorry to hear that your mother is having difficulty with access.Best Wishes.

author: PinheadBE
author_rank: Regular Contributor
timestamp: March 11, 2015, 06:14:18 pm
content: I understand and totally agree with you, Muttley, on the security aspects as you describe them, but here are some elements I will give to give some more precision.- There is no digicode access installed. All the inhabitants only have their old school physical key to open that door, and the electronic opener from within their apartment to open for visitors.- Emergency services would not rely on an electric opener in case of fire, for example. And in case of other emergencies, the door can be forced open by a screwdriver or a simple steel bar.- We are not very concerned by theft and things like that. That's why the level of security may appear so low.The only thing here is that old people and/or people with disabilities can not turn the key of the main entrance door (which is pretty hard to turn) and in the same time pull the door open (which is fairly heavy for oldsters).Unfortunately, when it was asked to the co-owners committee to foresee the possibility to use remote control access in the new system, it was discarded, because the majority didn't want to have to pay an extra couple of euros. Their decision was that the people who need it must find a solution on their own (as I did with the old system and my RC opener)And that's precisely where we are in now.We could go on a legal course, and have a solution in maybe ... a year or two (yes, that's how it works here....)So, as you can see, I have not a lot of options left besides a clean "hack" of that Aiphone system.So once again, if anyone has a technical information (besides the usual mounting plans that are found on the official website) on the protocol used on that 2 wire bus, or the full schematics of the GT-1D v2 unit, I would be delighted(May be sent by PM if you do not want a "public" release ... I would respect that)Anyway, thanks Muttley for your opinions and thanks to all for all help that could be provided.

author: Rory
author_rank: Frequent Contributor
timestamp: March 11, 2015, 06:48:50 pm
content: You know, it would probably be better if your mother could be able to call one or more of her neighbors to buzz her in. Why go through all this rigamarole when folks can look out for one another?

author: kolbep
author_rank: Frequent Contributor
timestamp: March 11, 2015, 07:48:16 pm
content: QuoteOk, then if they have said that, then you have basically an open invitation to do what you want.If you follow the wires from the door solenoid lock, eventually you will find that they go to a relay (either built into the Main Entry Doorstation, or a powersupply/controller box nearby). You will also, at that same point, find a 12v supply for the Intercom itself.Take a remote control receiver, hook it up to the 12v at that point, Now your receiver has power.Then (if it is a Strike Lock that needs power to open [and the Intercom relay is thus Normally Open], then just hook your receivers Normally Open contacts in parallel with those contacts on the builtin relay.Of Course, if the lock is one that releases when power is removed, then hook your receivers normally closed contacts in Series with the intercom's builtin relay.Stick a note on the receiver with your name and number, in case a technician needs to query why it is there (in future)And there you go.What you could even say to the Body Corp (and this might get them to be more accepting of you adding a receiver onto the system in the common property area), is tell them that you will do the above. Then program in a few remotes, and leave them with your family member (that lives there). If any other tenants then want a remote, they can purchase it directly from your family member (Maybe at cost price + a small charge for a programming fee - But that will be up to you. If you just want to charge cost on the remotes then that will be your own initiative).But, 1 more thing to remember. If you do not go for a complex (townhouse) receiver, then if somebody looses their remote, you might have to get all the remotes back, erase the receiver, and reprogram them all.The townhouse receiver will allow you to delete a specific remote. For that you will have to keep track of which remote is in what memory location in the receiver, and then note which owner / unit number the remote was given to.Although you say security is not paramount, if 1 or 2 remotes go missing, if found (and if the owner has a keychain with identification details on it), then some oppertunistic shopper can just walk in the front door.

author: miguelvp
author_rank: Super Contributor
timestamp: March 12, 2015, 08:13:40 am
content: Remember those old DTMF programmable dialers? you could store some numbers and you just put them to the microphone part of a phone handset and press a button or two and it will dial....So, She can push her unit button to call in. You have to have something that listens for the ring (or is wired to the ring circuit of her handset inside her place) that takes the phone out of hook via some micro controller, and generates a tone to let her know the device is ready for the preprogrammed touch tone code. If the right sequence of DTMF signals are received on the hacked handset, it activates the open door button.This way you don't have to hack the actual system, just the handset at her place.Don't want to touch the handset? then servos to press the intercom button and if the right DTMF code is sent a 2nd servo to activate the open door switch. Totally non invasive way to get around the problem.Or maybe voice recognition, and she just has to say "It's me!" to a trained speaker dependent system.probably a ton of other options that don't require hacking the system.But as Rory says, she can always call the neighbors to let her in, although after a while they might get annoyed if she needs their service often, then again she can in return do the same for them as he proposes. Win/Win!

author: Torbjorn
author_rank: Newbie
timestamp: July 22, 2017, 03:23:37 pm
content: Did you get any further with this?I kinda have the same problem. Have not been able to find out what sort of communication protocol aiphone gt-series are using.

author: PinheadBE
author_rank: Regular Contributor
timestamp: July 22, 2017, 07:51:40 pm
content: I stopped searching. My mother has since moved.But to satisfy my curiosity, I am still monitoring this topic