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Low Frequency alarm for hearing impaired

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    Low Frequency alarm for hearing impaired

    RE: NFPA 72-2013 29.3.8.1


    Does anyone know of a smoke alarm with a low frequency (520 hz) sounder?


    Does any one know of a 120V low frequency (520 hz) sounder? (could be connected to smoke alarms via relay)

    #2
    I forget what exactly is on the interconnect red wire of detectors that have it. Std is 9v, I just not sure if that is dc or ac. But you could harness that signal to turn on something else.

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      #3
      Originally posted by FionaZuppa View Post
      I forget what exactly is on the interconnect red wire of detectors that have it. Std is 9v, I just not sure if that is dc or ac. But you could harness that signal to turn on something else.
      It's 9 volts DC. But you need to look at codes and regs to see if you can tap into it or not.
      Cheers and Stay Safe,

      Marky the Sparky

      Comment


        #4
        Originally posted by olc View Post
        RE: NFPA 72-2013 29.3.8.1


        Does anyone know of a smoke alarm with a low frequency (520 hz) sounder?


        Does any one know of a 120V low frequency (520 hz) sounder? (could be connected to smoke alarms via relay)
        The problem with 520 Hz sounders is that these are actually speakers, not piezo sounders. That means they are real power hogs. You could never make one that was only battery operated. No one that I know of currently has 520 Hz smoke alarms.

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          #5
          Originally posted by K8MHZ View Post
          It's 9 volts DC. But you need to look at codes and regs to see if you can tap into it or not.
          Dont need to tap it. Just need e field sensor by the wire

          Comment


            #6
            Originally posted by gadfly56 View Post
            The problem with 520 Hz sounders is that these are actually speakers, not piezo sounders. That means they are real power hogs. You could never make one that was only battery operated. No one that I know of currently has 520 Hz smoke alarms.
            These meet NFPA 72 code spec
            520Hz, and not a speaker
            http://www.ti.com/lit/ug/tidu994a/tidu994a.pdf

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              #7
              Originally posted by FionaZuppa View Post
              Dont need to tap it. Just need e field sensor by the wire
              The 9v signal wire is run in the same cable as the 120 VAC powering the alarm so a field sensor may be problematic.
              Cheers and Stay Safe,

              Marky the Sparky

              Comment


                #8
                Originally posted by FionaZuppa View Post
                These meet NFPA 72 code spec
                520Hz, and not a speaker
                http://www.ti.com/lit/ug/tidu994a/tidu994a.pdf
                Not so fast there, sunshine. This is a PCB that contains all the fixin's for a compliant product, but it ain't the thing itself. System Sensor, Wheelock, Gentex, etc will have to incorporate it into a product that meets UL1971 (strobe) and UL 464 (low Hz sounder).

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                  #9
                  Originally posted by K8MHZ View Post
                  The 9v signal wire is run in the same cable as the 120 VAC powering the alarm so a field sensor may be problematic.
                  Not really. They are pigtailed in a box, so you push the 120 to one side, and keep the control wire on the other side, tape sensor to signal wire, hook sensor back to what device will alarm when voltage is detected on signal wire.

                  Hence, no tapping and no trying to get to the signal wire outside of the typical 4wire NM.
                  You could also add a jbox in attic (if possible) and simply remove some sheath from the wire, separate the wires, add sensor there.

                  And just for as-example, one tiny 20cent FET can be wired to be a near-field detector. Need to be smarter than the problem. This cat has many skinnings.


                  And just for clarity, I posted that Tex Instr PDF to show that a 520Hz piezo does exist. Was not saying to go buy those boards.

                  Comment


                    #10
                    Thanks for the replies.
                    The application would be a 1 or 2 bedroom apartment designated for hearing impaired.


                    Plan B is a small household fire alarm system 12V or 24V and use smoke detectors and AV alarms.

                    Comment


                      #11
                      Originally posted by olc View Post
                      Thanks for the replies.
                      The application would be a 1 or 2 bedroom apartment designated for hearing impaired.


                      Plan B is a small household fire alarm system 12V or 24V and use smoke detectors and AV alarms.
                      I'll recommend you call these folks to get some answers to the products that will work for your specific needs.
                      https://edwards-signals.com/

                      Comment


                        #12
                        Originally posted by olc View Post
                        Thanks for the replies.
                        The application would be a 1 or 2 bedroom apartment designated for hearing impaired.


                        Plan B is a small household fire alarm system 12V or 24V and use smoke detectors and AV alarms.
                        Use a bedshaker for sleeping quarters and a strobe accessory for waking hours.

                        Comment


                          #13
                          Originally posted by gadfly56 View Post
                          Use a bedshaker for sleeping quarters and a strobe accessory for waking hours.
                          What if they are blind?
                          You need items for blind and/or deaf people.

                          Bed shaker is a good idea.

                          Comment


                            #14
                            Originally posted by FionaZuppa View Post
                            What if they are blind?
                            You need items for blind and/or deaf people.

                            Bed shaker is a good idea.
                            Since the OP said "hearing impaired" I thought I'd try and break tradition and stay on topic.

                            Comment


                              #15
                              These are provisions for hearing impaired. There may never actually be hearing impaired people living there.
                              It is a specific requirement of the funding agency.
                              I have worked on a facility (group home) for deaf people before where we used bed shakers.

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