Door alert/chime

Discussion in 'The Projects Forum' started by m121212, Jul 24, 2011.

  1. m121212

    Thread Starter Active Member

    Jul 24, 2011
    71
    0
    Hi,

    I'm interested in making a door alert/chime, and wanted to collect suggestions and ideas before I start.

    The door chime has a magnetic sensor and a transmitter unit that wirelessly triggers the chime of a distant receiver unit.

    There are lots of products for sale that almost do what I want, but nothing quite perfect. A lot of them have limited range (< 200ft line of sight, less through walls), or only single receivers. I want to have multiple receivers (so that I can hear the chime upstairs, or in the basement, as well as on the ground floor).

    I'd like to have some type of modulation or encoding to limit eliminate incorrect alerts.

    I can probably come up with an op-amp circuit that can do this, but thought there might be ICs available that handle a lot of this stuff. Perhaps I could even repurpose some existing products to do exactly what I want.

    Does anyone have any recommendations for an easy way to accomplish what I want? If not, perhaps some recommendations on circuit topology?

    Thanks!
    m121212
     
  2. castley

    Member

    Jul 17, 2011
    31
    0
    Using babyminder will give you all the range you need
     
  3. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    By "door alert chime" what do you mean. You want to know when someone presses a doorbell, or you want to know when someone is in close proximity to the door, or you want to know when someone opens a door?

    It appears that you want to hear it upstairs and in the basement and you want it wireless and transmittable throughout the house. Incorrect alerts seem only to apply in the second scenario above.
     
    Last edited: Jul 25, 2011
  4. m121212

    Thread Starter Active Member

    Jul 24, 2011
    71
    0
    I'd like to know when the door is opened. I'd like something like a two-tone chime (as opposed to a 120 dB alarm).

    Regarding incorrect alerts, i'm referring to a lightning bolt or other noise source creating a false positive at the receiver end. Encoding helps avoid this.

    The other bad thing that could happen is a missed alert - someone opens the door and the chime doesn't sound. I think the only way to help this is make sure you have a good sensor system with well tuned sensitivity.

    I was hoping there was an IC available that handles the TX/RX and encoding, one low level enough for this simple application. I'm able to find many transceiver ICs for really complex digital comms applications, I don't want any of those.

    Babyminders sound interesting but expensive. Maybe garage door openers? Though ours at home only gets about 75 ft of range.
     
  5. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    Are you afraid of a few wires? A magnet proximity sensor attached to door and door jam connected to a simple two-tone chime with 2 speakers, one upstairs and the other in the basement.

    The following circuit could be modified to fit your needs.
    Two Tone Door Chime

    Another possibility:
    Basement alarm

    Another:
    Two Tone Generator
     
  6. m121212

    Thread Starter Active Member

    Jul 24, 2011
    71
    0
    Wires are no good for this situation; the wires would have to be very long and would get in the way. This is begging for a wireless solution.
     
  7. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
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    I have a 3-pack of these and they work through walls. The range is quoted at 100ft. You would have to hack it and add some circuitry.

    Remote Controlled Switch Socket - 3-Pack
     
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