I have a old landline intercom in my building, and I always forget my keys. So I thought if I connected a arduino to my landline, then I'd ring it, and maybe the arduino can pick up and if the right DTMF tones or keys are pressed (like a password on the intercom) then it would send DTMF tones back, which would result in the door opening. I dont think it would be hard, but obviously I'm not good at coding at all so I'm just looking for some help here. And before you ask NO this landline is not connected to public lines, only private voip lines in the building, as far as i know. I would really appreciate the help, and if anyone could find me parts, and maybe even code, and debug for me that would be greatly appreciated (we can discuss a form of payment if wanted). Another thought is just connecting the arduino directly to the phones audio output, decoding DTMF then just using arduino as a relay and attacthing it to the button. THANKS AGAIN!!!
Are you good at working out the 'hardware', the electronics?
Perhaps you could use an old desktop, dial-up modem still
hmmmm im not that old so i wouldnt really know how to use dialup but i am pretty good w/ hardware..
you can find simple DTMF decoder modules based on MT8870 which decode to BCD:
https://s.click.aliexpress.com/e/_DFcvLLd
You will also find modules with an additional BCD decoder for 16 outputs
https://s.click.aliexpress.com/e/_DDl5oWJ
and ready made versions with relays
https://s.click.aliexpress.com/e/_DD6zcKR
A quick search found this:
I'm sure there are others.
The relay seems nice. Though in the desc of the page, I cant seem to find the data sheet/ how to program? I might be just stupid.
I am aware of dtmf decoding chips, but the only problem is I would have to make a whole circut and I would have to code. I am familliar with some basic C+ and others but not enough to make use of these by using libraries. Thanks for the suggestion, though.
usually the relay modules can be set to different modes.
eight modes of operation:Non-locking (Momentary ), self-locking (Toggle),inter-locking (Latch), 5/20/60/120/250-second delay
I guess the mode is set with the 3 solder pads.
If you want to use something with the Arduino and do some low level programming consider the first or second product.
This project will get you most of the way there.
https://drive.google.com/file/d/0BwvMUg2LVaTraVdkeG5zbHoyWWc/view?resourcekey=0-jwcLybiZMsW_yXOVA2dnQw
How will you interface with the phone in your unit: go off-hook, couple with the handset and all that?
DTMF'ing and so on is the least of it.
I'm sorry, can you elaborate? I dont get a single thibg you just said.
Thanks! I will try it iut when i get home.
Yes I saw the modes of operation but how do I set what the relays trigger to? I'm really not able to think right now. EDIT: nvm i see now
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