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Home Speech recognition for Home Automation

Discussion in 'Electronic Design' started by Soren, Sep 9, 2007.

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  1. Soren

    Soren Guest


    I'm looking at possibilities of constructing a relatively cheap home
    speech recognition system to turn appliances on and off. As i see it I
    have several options:

    - Use a computer: Pros: Good Software is easy to get, Probably the
    fastest way to get a system. Devices could be run from the serial/
    parallel port.
    Cons: Expensive solution for such a
    "simple task". Computer must be dedicated and run all the time = high
    power consumption = expensive.

    - Build a system from speech recognition IC's or Microcontrollers:
    Pros: Components are relatively cheap, Low
    power consumption, Good recognition rate
    Cons: Components are often SMD's (haven't
    found any that are not) which means specialized equipment is to be
    used. Demo/development boards costs too much to justify its use. Maybe
    long development time.

    - Buy Specialized solution:
    Pros: Plug'n'play
    Cons: Extremely expensive, removes the fun
    of DIY :)

    What I really need is a robust recognition system that works with
    microphones not placed directly in front of the speaker.. like in the
    corner of the living room.

    Does anyone here know of such a system, or tried to develop one? It
    only needs to recognize 5-10 words. It's really a "toy" project.

  2. If you wait until end of month Asus will come out with a Linux based
    198$ laptop, the Eee PC, run perlbox voice on it.
    Perlbox-voice is user independent, needs no training, and that PC platform
    cannot be beaten for cost.
    As to far away mikes, it may or may not work depending on environment
    Beware of false triggers too.
  3. Soren

    Soren Guest

    Nice, Thanks for the tip! I'm not sure about Eee PC, the price in
    Denmark will be close to what I could build a server for myself (also
    using old parts i have lying around). I didn't know about perlbox, and
    thats very interesting, since I could then run Linux, and save alot on
    required hardware specifications.

    As for the microphones... yes it may prove difficult to get good
    recognition if im far away.. multiple microphones could maybe solve
    it.. but then I have to come up with a way to use multiple microphones
    on one input, and isolate speech from noise and echo.
  4. Ecnerwal

    Ecnerwal Guest

    If you have a good magnifier to see what you are doing (or a pair of
    "strong" reading glasses), skinny solder and a soldering iron with a
    fine point, SMDs are no big deal to hand solder. Really.
    That's good. I find the idea of the overly automated house rather
    difficult to grasp the appeal of - whether the "my house is online"
    version (Hackers broke into my house systems and...) or the voice
    control version (I was on the phone, and the house went berserk
    listening to the conversation). Having a computer or microprocessor
    collate and coordinate house systems seems fine, the methods of control
    should be quite well defined so that the odds of unpleasant conditions
    are reduced to a practical minimum.
  5. Soren

    Soren Guest

    Thanks for the tips everyone!

    I found an IC that looks like the thing I need... its a HM2007(P) ..
    now I have trouble finding a place to actually buy it.. the problem
    is.. i only need 1. not import 100..

    Does anyone here know where to buy a HM2007 ? I found the datasheet

  6. From your description(s) some things came to mind.
    Have you ever used keyfinder which responds to whistle or handclap.
    They usually include the recognition of noise (microphone?) and respond
    by activating included noise producing circuit.
    Extremely convenient to start a "toy" project.
    Beware - in some of them batteries not included!

    Have fun

    Slack user from Ulladulla.
  7. Soren

    Soren Guest

    Thanks! Actually the idea came after i fell over a hand clapping
    circuit, used to turn appliances on/off. However, i wanted something a
    bit more advanced.. with less chance of false activation. The hand
    clapper switch is just set off by a loud noise... (i'll build one
    anyway though:)) so is the keychain wistler (had one of those once).
    Also, by connecting a record/playback IC, i could make the HM2007
    "answer back". Which i think is pretty neat.

    While surfing the net for my HM2007, I found someone who did a Talking
    Toaster.. funny application.

    I got the HM2007, 10$ .. only problem is i live in denmark.. grr..
    everything costs a fortune in transport to have it sent. But it's not
    nice either to charge 24$ to send two IC's to Denmark! But the HM2007
    is out of production,... and these guys where the only ones that sold
    single quantities.

  8. About 5 years ago, I was volunteered to look at several local home
    automation system that included voice control. I have to look at my
    office records to find the vendors. They were similar to what you are
    looking for. You can walk into any room, say the secret prefix, and
    the various microphones would attempt to pickup your voice and
    initiate a command.

    At least that was the theory. The reality was quite different. It
    didn't work at all if there was any unusual background noise. Run the
    vacuum cleaner, TV, stereo, or even have a running conversation going
    in the same room, would cause a failure to communicate. The system
    solved this problem by muting the sources of audio that it controlled
    when it thought it heard a command. That meant that the TV and hi-fi
    audio were always going on and off as commercials tended to set off
    the speech recognition system. If there were several groups of people
    talking at the same time, the system would not recognize anyone's
    voice. Interestingly, when the washing machine was running, voice
    control within 2 rooms of the machinery would not work.

    My fast fix was to install telephone handsets in every room (on the
    existing control panels) and hot wire the voice control system into
    the telephone switch. The user had to punch in the proper prefix
    (extension number) before the system would recognize their commands.
    It was fascinating to watch a 3 year old command the system perfectly,
    while all the grownups had nothing but problems.

    Lots of commercial products around that will do voice control. You
    might want to buy or adapt one:
    < control>

    I've also played with voice control far back as the 1970's, where we
    used mechanically resonant fiber optic bundles (Sceptron or Spectral
    Comparative Pattern Recognizer) to recognize syllables for what
    eventually became an IVR (interactive voice response) system for a
    hospital pharmacy. Much later, I was doing battle with a system for
    use on a production test line to allow the tech to control the test
    equipment and still have use of both hands. That monster was
    eventually replaced by a totally functional foot switch and a few push

    I've never designed or even re-designed a speech recognition system.
    My involvement was to get involved after various companies or
    individuals had lost the battle with the system and were looking for
    someone to do damage control. That makes me a non-expert with a bad
    attitude with lots of field experience disarming or reconfiguring
    voice control systems.

    Not all such systems are useless or badly designed. I use Microsoft's
    Voice Command:
    quite effectively on my PDA phone (Verizon XV6700). MS also has
    various speech recognition products, some of which I've tried with
    widely varying degrees of success:

    One thing I learned quickly was that the system has to have a positive
    method of being enabled and disabled or there is going to be a serious
    falsing problem. That should be an "out of band" push button, motion
    detector, or key fob. It cannot be anything "in band" such as a code
    word or hand clap. That's what originally was causing all the
    problems with the home automation systems I "fixed". Also, there's
    security, which I never really addressed. You don't want the 3 year
    olds friends trying to take over the house (which has happened).

    I don't think that starting at chip level is the correct approach.
    There are plenty of relatively cheap IR remote control systems that
    offer voice control as a starting point. Most have about a 50 word
    trainable vocabulary. Use one of those to build your system. There's
    nothing preventing you from using the output to trigger a relay,
    switch, or device. The real problems are not in the hardware
    implementation or even in the recognition algorithms. They're in how
    the user interacts with the device and how you deal with error
    conditions and modes (i.e. software). You'll hit those soon enough.

    Good luck.
  9. Gary Tait

    Gary Tait Guest

    0.05" SMD I can do on perfboard.


    Any finer I'd go for some sort of pre-built board, perhaps doing some I/O
    on a .05 protoboard, or full sized DIP.

    If I were going to try, I'd find a ready to go SBC and get my hands dirty
    with software.
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