I'm a noob as far as Arduino is concerned and my knowledge in this area is also limited, but I'm willing and eager to learn. Right now, we are facing a real problem and I'm exploring if Arduino can help us:
We are a housing society of a few buildings and my specific building has 28 apartments. We have a security door at the ground level which is accessed by biometric and access cards. We also have intercoms. So when a guest visits, she calls the respective apartment and the host must come down to open the door. What I am looking at is a way to somehow avoid that visit downstairs everytime.
We can add "exit switch" in every apartment. But thats costly and too much wiring. Another option to install some sort of GSM relay switch, but then host must dial in again to a different number after or while guest is speaking on the intercom. Since the intercoms are placed right next to the biometric unit, I wonder if we can do something like this:
Visitor calls from intercom
Host picks up the phone and if satisfied, presses some key combination on landline (can be as simple as 1 to accept, 0 to reject and hang up)
If correct keys are pressed, Arduino at the ground floor activates a relay and open the door.
Is this realistic and possible using Arduino? Is there some ready-to-install kit available to solve this problem?
I don't know what the layout of your building is, but you might get away with 433 MHz. radio transceivers.
I' m using RFM22B's for an 8 node home sentry project; they can output (depends on antenna quality) 0.1 watts, which should give several hundred yards range open air. So if each apartment had a little box, which transmitted to a unit at the front door, you could activate a door unlock when a correct code was received. In order to enhance range, you could use a high quality antenna on the door opener unit, to boost effective radiated power. Also, this would also allow you to change the pass codes if renters moved out and took the door opener with them.
I bought the RFM22B's for about $5, mated them with a Nano on a purpose-built circuit board, which altogether costs about $10.00/board. I integrate this little board into any project that requires a radio. The resulting boards use five pins (2, 10, 11, 12, 13) to interface to the radio, allowing me the remaining pins for whatever functions are required and the Nano is still programmable in circuit, if you leave D0 and D1 alone.
If you message me, I'll supply you with the circuit board layout and my radio routines.
Grumpy_Mike:
What is to stop a visitor injecting these tones from outside into the intercom and opening the door?
Thanks for your reply. What I've in mind that each resident will have a passcode that they keep safe. So the key combinations will not be available for to the visitor. Moreover if the module can detect the end which is pressing the tones, thats even better.
pavanarduino:
We can add "exit switch" in every apartment. But that's costly and too much wiring.
But you just said you already have the wiring!
pavanarduino:
Is there some ready-to-install kit available to solve this problem?
Yes, from the company who fitted the security door and intercoms. That is a standard part of the intercom system. What you have to ask is why it was not fitted correctly in the first place?