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voice opearted switch

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New Member
hi all,

i am a new member and thoughrt that i would get some sort of educational help form teh more experienced memberor should i say professionals of the electronic world. .enought **** chat

i need to build a voice operated switch that switches on when i say ON, get dim when i say dim, and goes off when i say off. i am compleately new at electronics well i knwo that i need to check or analyze the wave form of the voice. but i am actually do not knwo where to begin the process of ho wteh voice is going to cause the component to switch from an open circuit to a closed circuit. i need to know about the circuit that i have to build and also the type of analysis that i need to incooperate in for the circuit to operate as said above

any help on what should be done would be of great apperation and ,also any links that has projects of that sort will eb of ever more importance to me

thank you
Alternative to Voice Recognition?

The subject of voice recognition is way beyond me - I don't think the big boys have really mastered it yet; it would require serious computing power to analyse a waveform and compare it to a pre-recorded sample. To have all this technology to achieve just a few commands seems OTT to me.

Could you consider an alternative such as clapping one, two, three times?
How about whistling three different pitches?

The above schemes are feasable but will suffer from false triggering if the background music/noise is too high.

What kind of lamp are you wanting to control? are you switching mains? (it makes a big difference to the method of dimming).
well actually it is for a project at colledge.

i thought that if i analize the waye formand then check the amplitiude of the wave or teh frequency i would be able to find three different switching capacitors to switch oanat a specific frequency or a specific amplitude.

i amnot actually switching mains. it is just a simple circuit that ensure that teh procedure can switch maybe even a battry powered lighting circuit .

what r yoru views
i was trying to fnd a way to do it without any software involved. i wanted to do it using only hardwae componetnts and no programing. i shat possibel, if so how and what components and circuits needed, also what instrument si used to analise hat circuit

Hi All,
He is just asking for a simple voice operated switch hat would respond to sharp sounds like clap. One clap will make the switch on and other would make it off. The basics is to attach a condenser microphone to input of a pre-amplifier and then drive a toggle filp-flop (IC or transistor based). Thus sharp pulses like clap received by mic. will serve as clock to the filp-flop and toggle its output.
I had built this circuit ages back. The circuit can be found on the next page:

well sorry but if u read the first mail that i posted u will see tha i only wanted to circuit to be operated by the process stated below. when i say ON the light will go on, when i say OFF the light will go off, and wheni say DIM the light will go dim.

that is much different from a sound operated switch that only operates when teh switch hears a sound. PLZZZZZZZZZZZZZ i need soem positive input i rreally do. am by the way if someone in london can build me or shwo me a circuit of soem sort of help i will be happy to put some money down for the help that the person offered but there are conditions.

I am sorry I misunderstood your question.
The method of voice recognition will include huge circuitry namely a microcontroller, large memory space, high resolution ADC etc. The trick is to store the sounds "ON","OFF" and "DIM" in memory. Now whenever the sound sample arrives, compare it with one within memory and do the job accordingly.
But this is not as simple as it sounds. It requires many processing on audio signal because the environment isn't same always. Like if you are recoding a sound in silent environment, the system won't work if you operate it in noisy environment. So Digital Signal Processing will also be requied to extract only vocal signal from the incoming audio and eliminate rest of the signals. :roll:

Could a Vocoder do it ?

I wonder if a stripped- down vocoder could do the voice analysis, giving the volume value of, say, twenty frequency bands; all twenty volume levels changing throughout the duration of the analysis would form the 'signature' of the command word.
A computer (via a bank of twenty 8 bit A-D converters) would analyse the twenty values and compare them to the recorded samples.

This sounds just about feasable, I can only guess how reliable it would be -- but still a massive overkill to replace three switches, an advanced college project :?:
20 ADCs? :shock: Oh My God !

I better suggest you use ONLY 1 DSP instead. :wink:

Scanner ?

OK, OK, OK -- compromise?
One ADC fed from a 20 input multiplexer, selecting one of the twenty filter envelope followers. 8)

The whole thing (vocoder and all) could be software but I'm a purist :wink: and still think in terms of circuitry rather than programs.

My idea was meant to be "food for thought" and suggests (correctly, I believe) at the complexity of this project, not its 'best' solution.

I wonder if sixteen channels would be enough :?:
Would a DSP be required if implemented in software, could'nt a microprocessor (with ADC) do the lot :?:

ps. I'm a technophobe :?
Yeh, Microcontroller can be put to do the job of a DSP. But it will take a lot of time to process the audio signal which a DSP can do in fraction of second. I am still favouring DSP 8). It has lot many advantages over crude old signal processing techniques. And the performance of your system is going to be awsome. :wink:
well, i have something that could help....
in a book i have a project that works for 10 commands, but u can use only 3 of them or how many u need.
it uses a IC called TC8860, wich contains a microprocessor, A/D convertor, ROM, etc. U have to record the commands, so it might only respond to ur voice.
that's all i can say now, couldnt find anything about the ic, maybe u are luckyer........ :lol:
I searched for TC8860 datasheet on the net but it seems its a rare IC. Yyou can try come other ICs which are easily available like the Philips "SBF1005 Hello IC".
You may study these files:
**broken link removed**
**broken link removed** (Some other company)
Hmm.. although I can't help with the electronics (I was a programmer by profession but still this is a little bit hard with voice recognition), it would be fun watching the lamps go on and off while saying something like "only going off-pist on your ski vacation is one of the best things on winter vacations out of sweden"


Albert "thec" Sandberg
Clap Switch

Im new to this stuff, and i tried doin a calp switch. The problem is i dont know how it works, the basic principle, what each component does, and the mechanism behind. I tried looking for it on the web but i found only clap switches based on IC and not Transistors :cry: . Plzzzzzzzzzz. can anyone help me on how a Transistor Clap Switch works?


P.S. : If anyone has a diagram or know whare i can get one, plz, inform me. Plus my e-mail address is
A clap switch is nothing but a simple bi-stable flip-flop which toggles its output (1 to 0 or 0 to 1) whenever a clock pulse is applied to it. In a clap switch, the sharp pulse created by a clap serves the clock to the flip-flop and ths it turns the connected device on and off.

Thanks. But i'm doing a project and i need to know the detailed mechanism. Is it possible for you to send me that info. Also i need it for a transistor clap switch not an an ic based one. Plzzzzzzz. Help me out here
as i need this stuff before the 1st of Feb. If u know a website which tells me this info, plz. give it to me. U can contact me directly using this address:
I did a quick search on google and found this:
**broken link removed**
I'me not sure if it's the right thing or not, I didn't really look into it but from what I read it's voice recognition system and there is a link to a schematic towards the end.
Long back I had built this clap switch the schematic of which is shown below. Hope this is what you want.


  • clapsw.JPG
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