Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

80FFTs Per Second To Detect Whistles (and Switch On Lights)

timothy posted about a year ago | from the this-is-awesome dept.

Input Devices 156

New submitter Mathieu Stephan writes "Hello everyone! Some people told me that my latest project might interest you. I'm not sure you publish this kind of projects, but here it goes. Basically, it is a small platform that recognizes whistles in order to switch on/off appliances. It will be obviously more useful for lighting applications: just walk in a room, whistle, and everything comes on. The project is open hardware, and all the details are published on my website." The linked video is worth watching for the hidden-camera footage alone: it would be hard to not keep playing with this sensor.

cancel ×

156 comments

Sorry! There are no comments related to the filter you selected.

Put your lips together and blow... (2)

Vombatus (777631) | about a year ago | (#43672159)

What could possibly go wrong?

Re:Put your lips together and blow... (2)

noh8rz10 (2716597) | about a year ago | (#43672173)

where is apk these days? this sounds like a $10,000 challenge...

Re:Put your lips together and blow... (0)

Anonymous Coward | about a year ago | (#43672487)

That's what she said!

Re: Put your lips together and blow... (-1)

Anonymous Coward | about a year ago | (#43672649)

That's not funny Lauren Bacall died that way.

as popular as the clapper! (0)

Undead Waffle (1447615) | about a year ago | (#43672165)

Clap on. Clap off.

Re:as popular as the clapper! (0)

Anonymous Coward | about a year ago | (#43672195)

Clap on. Clap off.

Yes, but with gestures. Here's one for you: ,,|,,

Re:as popular as the clapper! (3, Interesting)

Nutria (679911) | about a year ago | (#43672485)

Back in the 70s (when The Clapper first came out), we had a similar contraption that was basically a plastic whistle stuck to a hollow rubber ball. Squeeze the ball, the whistle whistles and the lamp turns on.

As a teenager I enjoyed it, but I'm sure the adults thought it got old really quickly.

Re:as popular as the clapper! (1)

GerryHattrick (1037764) | about a year ago | (#43672531)

We still have ours, but use it only for the Christmas tree lights. It will switch 13A at 240V, but that doesn't seem very safe.

Re:as popular as the clapper! (1)

SuricouRaven (1897204) | about a year ago | (#43672557)

British, then?

Most of Europe runs at 230V, but only the UK has 13A sockets - and it was 240V back in the seventies, before the EU agreed on a common voltage.

Re:as popular as the clapper! (1)

GerryHattrick (1037764) | about a year ago | (#43672761)

On this chilly Spring morning in England it is 234.9V. That's either a British compromise, or yet more evidence that we never did really want to join 'Europe'.

Re:as popular as the clapper! (1)

maxwell demon (590494) | about a year ago | (#43672883)

Actually, while the mean voltage is 230V, there's a tolerance interval of 10%, so the actual voltage at any time may be anywhere between 207V and 253V (actually, in the UK the lower tolerance level is at 216V, to avoid problems with old devices). In other words, you might measure 234.9V elsewhere in Europe (actually, it also was already inside the tolerance interval in Germany even when the German voltage was just 220V).

Re:as popular as the clapper! (1)

rossdee (243626) | about a year ago | (#43673025)

"Actually, while the mean voltage is 230V"

Its AC - the mean voltage should be zero

Re:as popular as the clapper! (2)

lxs (131946) | about a year ago | (#43673561)

I'm pretty sure he's talking about the RMS [wikipedia.org] value. Or an approximation thereof if he uses a cheap multimeter.

Re:as popular as the clapper! (0)

Anonymous Coward | about a year ago | (#43672625)

Making a loud enough "SSSssss" noise did the same thing as the plastic sqeeze-ball whistle doodad, but was much less attention getting than clapping. A sort of fun way of messing with lights when you know people had them plugged into that thing.

Re:as popular as the clapper! (0)

Anonymous Coward | about a year ago | (#43673271)

We had one of these when I was a child, in the '70s. It was called (obviously) the "Whistle Switch". We lost the squeeze bulb whistle, but discovered that almost any loud noise would turn the light on, or off. As children, my siblings and I thought that it got old quickly!

Re:as popular as the clapper! (0)

Anonymous Coward | about a year ago | (#43672489)

And once you got it, it's really hard to get rid of the clap too.

FFT (0)

Anonymous Coward | about a year ago | (#43672185)

80 But why, your limiting your frequency range by your time domain range...derp derp

Multiple rooms (4, Funny)

Dan East (318230) | about a year ago | (#43672197)

Interesting idea, but I think there would be serious scalability problems. Imagine if this was in each room in your home, and the doors to the rooms were open. Whistling in one room would almost certainly trigger the lights in the adjacent rooms as well. You would run into similar issues trying to control multiple lights in the same room independently, unless you started getting into more complex whistle patterns then those shown in the video. In that case you would start to sound like a songbird, or maybe R2D2.

And finally two side notes...
Not for use in emergency situations while eating saltine crackers.
This method of controlling the lights would be extremely popular in the von Trapp house.

Re:Multiple rooms (0)

Anonymous Coward | about a year ago | (#43672213)

Not necessarily. You could connect all your receivers together somehow, weight their inputs and get the one that has the strongest signal.

Re:Multiple rooms (1)

dgatwood (11270) | about a year ago | (#43672503)

A better solution would be to pick the microphone where the sound arrived first and reject that frequency on all other mics until about a second after the first microphone loses the signal. That way you're guaranteed to get the one that is closest in distance even if there are gain differences caused by variations in room acoustics.

Re:Multiple rooms (1)

St.Creed (853824) | about a year ago | (#43673349)

Unfortunately, it's pretty hard to determine which frequency arrives first, since frequency is the number of wavetops arriving over time. If you have a very small sampling interval in which to determine frequency, your sampled frequency starts to deviate from the real frequency really fast.

Re:Multiple rooms (0)

Anonymous Coward | about a year ago | (#43672369)

"It has a 15 feet listening range..."

Re:Multiple rooms (1)

xstonedogx (814876) | about a year ago | (#43672377)

The real danger is watching Star Wars with these in the room. *R2 sad whistle*

Re:Multiple rooms (1)

Molochi (555357) | about a year ago | (#43672415)

Funny. But the last time I tried using any kind of auditory control I found that I would have to give up music and movies to get it to work.

Re:Multiple rooms (5, Funny)

houghi (78078) | about a year ago | (#43672737)

You would run into similar issues trying to control multiple lights in the same room independently,

That can easily be solved. All you need is a switch to decide what light you want to trigger. You could place that switch near the door, so you can do it the moment you come in.

Re:Multiple rooms (4, Funny)

Custard Horse (1527495) | about a year ago | (#43672897)

All you need is a switch to decide what light you want to trigger. You could place that switch near the door, so you can do it the moment you come in.

A ridiculous idea - it'll never catch on!

Re:Multiple rooms (4, Insightful)

gnasher719 (869701) | about a year ago | (#43672821)

Interesting idea, but I think there would be serious scalability problems. Imagine if this was in each room in your home, and the doors to the rooms were open. Whistling in one room would almost certainly trigger the lights in the adjacent rooms as well.

Typical slashdot combination of the Nirvana fallacy (a solution that isn't 100% perfect is not acceptable), and a totally defeatist attitutude to technical problems.

Re:Multiple rooms (1)

maxwell demon (590494) | about a year ago | (#43672891)

A solution which fails in typical situations is not just not 100% perfect, it's seriously limited.

However, in this case I doubt that this specific problem actually exists: It should be trivial to have the lights in different rooms react to different frequencies.

Re:Multiple rooms (1)

Hentes (2461350) | about a year ago | (#43673627)

In a case where we already have a 100% perfect solution, then of course it's unacceptable.

Re:Multiple rooms (2)

Mathieu Stephan (2892907) | about a year ago | (#43672895)

Hi! Actually if you put one whistled in one "inside" room corner this won't happen :) The microphone is omnidirectional, but not that much :)

Re:Multiple rooms (1)

StripedCow (776465) | about a year ago | (#43672997)

Imagine if this was in each room in your home, and the doors to the rooms were open.

If you want to separate a signal based on multiple sources, then there are algorithms for that.
Have a look here: http://en.wikipedia.org/wiki/Kalman_filter [wikipedia.org]

This type of filter has been used, for example, to separate the heartbeat signals from a mother and her fetus, using multiple sensor elements (one close to the mother's heart).

Re:Multiple rooms (0)

Anonymous Coward | about a year ago | (#43673047)

The image that came to my mind, for some messed up reason, was someone whistling in their house, then suddenly it exploded.

I just woke up, sue me. I can't help it that I have psychotic dreams and dreams of being the overbrain that controls the sentinels from the Matrix devouring cities in my way.

I mean what?

Prior art from the 1950s... (2)

crankyspice (63953) | about a year ago | (#43672199)

http://www.washingtonpost.com/wp-dyn/content/article/2007/02/16/AR2007021602102.html

Just... (2)

SuperKendall (25149) | about a year ago | (#43672201)

Just whistle while you work!

WShreee.... Click!

*Dammit*

fucken retards (-1)

Anonymous Coward | about a year ago | (#43672203)

Fucken retards.
1:9 Ye looked for much, and, lo it came to little; and when ye brought
it home, I did blow upon it. Why? saith the LORD of hosts. Because of
mine house that is waste, and ye run every man unto his own house.

1:10 Therefore the heaven over you is stayed from dew, and the earth
is stayed from her fruit.

1:11 And I called for a drought upon the land, and upon the mountains,
and upon the corn, and upon the new wine, and upon the oil, and upon
that which the ground bringeth forth, and upon men, and upon cattle,
and upon all the labour of the hands.

1:12 Then Zerubbabel the son of Shealtiel, and Joshua the son of
Josedech, the high priest, with all the remnant of the people, obeyed
the voice of the LORD their God, and the words of Haggai the prophet,
as the LORD their God had sent him, and the people did fear before the
LORD.

Re:fucken retards (4, Funny)

Concerned Onlooker (473481) | about a year ago | (#43672223)

See, that's why the bible is so hard to believe. There's just no way all those things happened one minute apart.

Re:fucken retards (1)

OhANameWhatName (2688401) | about a year ago | (#43672353)

Fucken retards

If there's swearing in the bible, it might be worth a read.

Re:fucken retards (2)

maxwell demon (590494) | about a year ago | (#43672925)

Maybe someone should write the "Fucking Bible":

"In the beginning god created the fucking heaven and the damn earth. And the earth was bloody formless and goddamn empty ..."

Re:fucken retards (0)

Anonymous Coward | about a year ago | (#43673607)

On the seventh damn day he rested and said it was damn good. Then he rested damn it.

And he said "Where can I get some Damn bait!?!"

Re:fucken retards (0)

Anonymous Coward | about a year ago | (#43673705)

You should read the Bible.

To pique your interest, I'll recommend you start with Ezekiel 23:20.

I remember seeing a whistle device... (4, Interesting)

ls671 (1122017) | about a year ago | (#43672215)

I remember seeing a whistle device that you attach to your key ring. When you lose your keys, you whistle and your key ring beeps.

https://www.amazon.co.uk/Tobar-Keyfinder-Keyring-Whistle-Activated/dp/B000246JIQ [amazon.co.uk]

Re:I remember seeing a whistle device... (1)

mvar (1386987) | about a year ago | (#43672399)

Now that's a blast from the past..in the 80s these were quite popular

Re:I remember seeing a whistle device... (1)

93 Escort Wagon (326346) | about a year ago | (#43672551)

Now that's a blast from the past..in the 80s these were quite popular

I don't think they were popular back then. While I saw them on late night television commercials all the time, I never met anyone who actually owned one.

Re:I remember seeing a whistle device... (1)

newcastlejon (1483695) | about a year ago | (#43672731)

A blast from the past indeed. [youtu.be]

Re:I remember seeing a whistle device... (0)

Anonymous Coward | about a year ago | (#43672749)

In the netherlands there were very popular.
I think almost half the households had one.

Re:I remember seeing a whistle device... (0)

Anonymous Coward | about a year ago | (#43673503)

Living daylights?

Re:I remember seeing a whistle device... (1)

TheInternetGuy (2006682) | about a year ago | (#43672409)

I remember seeing a whistle device that you attach to your key ring. When you lose your keys, you whistle and your key ring beeps.

https://www.amazon.co.uk/Tobar-Keyfinder-Keyring-Whistle-Activated/dp/B000246JIQ [amazon.co.uk]

Yes it is a problem that can be solved with very simple analog electronics. That was my first thought when I read the summary, but I guess that wouldn't be cool today.

Re:I remember seeing a whistle device... (1)

dgatwood (11270) | about a year ago | (#43672519)

Even funnier is putting a bunch of those things in the same room, whistling, and laughing as they set each other off. Bonus points if you do this on the shelf at Wal-Mart.

Re:I remember seeing a whistle device... (2)

Inda (580031) | about a year ago | (#43672863)

I bought a friend one because he's always losing his keys; losing them at my house *facepalm*

It goes off when he's got the radio on, when a door creaks, when dogs bark, when his phone goes off... Well worth the couple of quid I spent on it. muhahaha

Clap on Clap off (0)

Anonymous Coward | about a year ago | (#43672241)

http://www.amazon.com/The-Clapper-Sound-Activated-Switch/dp/B0000CGKLR

This has been done, kind of. (1)

Animats (122034) | about a year ago | (#43672271)

The Clapper. [wikipedia.org]

Re:This has been done, kind of. (1)

DigiShaman (671371) | about a year ago | (#43672505)

Clap on *clap clap*! Clap off *clap clap*! Clap on clap off; the Clapper.

http://www.youtube.com/watch?v=cfgN5tUgjb8 [youtube.com]

The ultimate in 80s cheese.

Kids These Days... (3, Interesting)

lobiusmoop (305328) | about a year ago | (#43672275)

They've got so much cheap compact compute horsepower to play with, it's almost obscene. 2048-wide FFT? In my day you would be overjoyed with a simple time-domain autocorrelation pitch detector.

(Lawn, etc...)

Re:Kids These Days... (0)

Anonymous Coward | about a year ago | (#43672345)

Thank you. I'm glad someone suggested a more sane approach to the detection problem :) FFT's seem like total overkill for the problem at hand.

Re:Kids These Days... (1)

kermidge (2221646) | about a year ago | (#43672645)

Reminded me of the formulas and tables in ye olde CRC Handbook. Neat project, tho.

Re:Kids These Days... (4, Interesting)

jmv (93421) | about a year ago | (#43672655)

Actually, an FFT is often cheaper than autocorrelation because it's N*log(N) whereas auto-correlation is N^2. In any case, it's insanely cheap on today's machines.

Re:Kids These Days... (1)

Casandro (751346) | about a year ago | (#43672911)

You can do auto- and crosscorrelation in linear time in frequency domain.

Re:Kids These Days... (0)

Anonymous Coward | about a year ago | (#43673051)

So you need an FFT to get into the frequency domain, and then back. So your complexity is still N*log(N)

Re:Kids These Days... (1)

Anonymous Coward | about a year ago | (#43673537)

Not N^2, N*P, where P are the number of frequencies you want to check. This makes it good for pitch detection, where you care about a limited number of pitches, and would need pretty high resolution on the FFT since the bins don't align with your desired frequencies.
It can also do streaming updates, while FFT is typically used on overlapped windows.

Voice-activated doors (1)

Anonymous Coward | about a year ago | (#43672281)

Does it work like the voice-activated doors in Airplane 2 [youtube.com] ?

Re:Voice-activated doors (1)

xstonedogx (814876) | about a year ago | (#43672389)

The fictional future is always so much cooler than the real future.

Re:Voice-activated doors (2)

Zontar The Mindless (9002) | about a year ago | (#43672623)

We got Star Trek's communicators without their Eugenics Wars of the 1990s.

I'd say the real future is working out pretty well so far. I'm happy.

Re:Voice-activated doors (1)

isorox (205688) | about a year ago | (#43672943)

Really, we have hand held devices that can talk to another on the other side of a planet *without any infrastructure, not even an orbiting ship*?

Re:Voice-activated doors (0)

Anonymous Coward | about a year ago | (#43673079)

Really, we have hand held devices that can talk to another on the other side of a planet *without any infrastructure, not even an orbiting ship*?

Yes, their called HF radios. People routinely do exactly this with fancy algorithms and just a few watts of transmit power.

Re:Voice-activated doors (0)

Anonymous Coward | about a year ago | (#43673437)

"They're", it's "they're" (short for they are), for fuck's sake.

Wasn't this a joke? (0)

Anonymous Coward | about a year ago | (#43672315)

I could have sworn some TV show made a joke about such a device, with the inventor seemingly unaware that clapping is easier than whistling. I guess life does imitate art.

Re:Wasn't this a joke? (1)

Cenan (1892902) | about a year ago | (#43672755)

I'm pretty sure I've seen that bit on the Simpson's but I can't find a reference for it.

New generation of pranksters (1)

macraig (621737) | about a year ago | (#43672447)

If this device becomes a commodity found in every home, it will spawn a whole new generation of pranksters who will sneak up to houses and "hack" the lighting and appliances with a whistle. We'll wind up needing two-factor authentication for our whistle-houses.

Re:New generation of pranksters (0)

Anonymous Coward | about a year ago | (#43672635)

Maybe we can call them "house-phreakers".

Re:New generation of pranksters (1)

macraig (621737) | about a year ago | (#43672643)

Woz would like that!

Re:New generation of pranksters (1)

isorox (205688) | about a year ago | (#43672945)

If this device becomes a commodity found in every home, it will spawn a whole new generation of pranksters who will sneak up to houses and "hack" the lighting and appliances with a whistle. We'll wind up needing two-factor authentication for our whistle-houses.

Just like the problem of people waking around firing infrared through the window at your tv and changing the channel?

Pranks can cost u.. (1)

maniya (2918623) | about a year ago | (#43672569)

Nowadays one finds individuals whistiling on roads and that can be of gr8 problem.. Anyways it might be more expensive

Could be done a lot cheaper (1)

Casandro (751346) | about a year ago | (#43672583)

Just hook up your microphone to a schmidt-trigger. Your output will have your dominant frequency in it. Often the inputs of your microcontroller will already have schmidt-triggers, look at the data sheet, if not get a controller with a built-in op-amp.
Then just count the zero-crossings, by having one timer count them, and having another timer regularly looking at the output of the first counter.

The great advantage is that you can use much cheaper microcontrollers, which need much less power and have much less stringend power requirements, also saving you the switchmode power supply. That is, of course, at a slightly lowered sensitivity.

Re:Could be done a lot cheaper (1)

Thor Ablestar (321949) | about a year ago | (#43673065)

And what will you do with a noise that randomly falls into the frequency window?

Re:Could be done a lot cheaper (1)

Casandro (751346) | about a year ago | (#43673077)

Well low noise would not trigger the Schmidt-Trigger. Noise that will trigger it will trigger it randomly. so you'll end up with a frequency of zero crossing that randomly changes.

Sir, I salute you! (1)

Black Parrot (19622) | about a year ago | (#43672589)

We can tell you've got teh True Geek... ...a normal guy would have made it make the girls' knickers fall down.

Turning on lights? (1)

SeaFox (739806) | about a year ago | (#43672609)

I can whistle and get a sandwich, now that I'm married.
Sometimes I have to added "sudo" before it, though.

Re:Turning on lights? (2)

maxwell demon (590494) | about a year ago | (#43672949)

In the past, there have been much more interesting things [wikipedia.org] you could do by whistling ...

Re:Turning on lights? (1)

isorox (205688) | about a year ago | (#43672951)

I can whistle and get a sandwich, now that I'm married.
Sometimes I have to added "sudo" before it, though.

I whistle and get a bowl of bolognaise.

Tipped over my head.

You insensitive clod! (2, Funny)

Anonymous Coward | about a year ago | (#43672767)

I can't whistle!

Old electrical engineer here (0)

Anonymous Coward | about a year ago | (#43672785)

I applaud the enterprising spirit, but am a bit surprised at the complexity of the device (had a look at the schematic) and the fact that it uses a powerful microcontroller, for something that could be achieved with two transistors, a tiristor and a few passive components. It would be a lot sturdier, too. Also, it would last much longer than the solution presented here, since it doesn't need any programmable memory (which is estiated to survive about one decade). Yes, ten years seems like a long time, but typically, electrical switches last much longer, and implementing this whistle-switch with the three active components I mentioned, would guarantee that it lasts practically indefinitely.

Re:Old electrical engineer here (1)

Casandro (751346) | about a year ago | (#43672929)

Well if you have a hammer everything looks like a nail. Those kids don't know anything else than FFT. It's a shame really.

New Electrical Engineer here (0)

Anonymous Coward | about a year ago | (#43673377)

What's a transistor? Can I write code for it in C++?

FFT's ? kids these days (1)

darkHanzz (2579493) | about a year ago | (#43672877)

In my day we would use a couple of IIR filters, instead of FFT's. Much faster, better control over bandwidth. But, hey, then you'd actually have to do some math to design them....

Re:FFT's ? kids these days (2)

ikaruga (2725453) | about a year ago | (#43673107)

FFTs will allow the analysis of all frequencies up to half the sampling frequency using a single algorithm per execution. A processing method using IIR filters can only be used for a single band/filter. If whistles were the sole application I would agree with you(heck, I'm just a 27 old recently graduated from my PhD course and I think I could do that using only analog components). But the developer himself talks about other applications that could use other sounds. Instead of implementing and executing different IIRs for every single application, using a single FFT is far more productive. Plus, we're in the second decade of the 21st century. Unless there is explicit need to do so or you're a passionate about optimization, our hardware can handle "bloat".

Re:FFT's ? kids these days (1)

Viol8 (599362) | about a year ago | (#43673353)

"our hardware can handle "bloat"."

Your average modern car could probably handle carrying half a ton of lead in the back and still out accelerate the equivalent from the 60s. Does that make it sensible to carry the lead around when you could quite easily take it out - ie make the car much more efficient and even faster?

FFT's for a whistle detector? Goertzel ... (0)

Jimbookis (517778) | about a year ago | (#43672879)

... is spinning in his grave. Call me when the OP trips over this Wikipedia entry. http://en.wikipedia.org/wiki/Goertzel_algorithm [wikipedia.org]

Re:FFT's for a whistle detector? Goertzel ... (1)

Thor Ablestar (321949) | about a year ago | (#43673031)

To use Goertzel, you basically should need to know the frequency of whistle beforehand. It's nice when you have a fixed-frequency whistle but bad if you whistle by mouth. The autocorrelation algo or any other pitch determination algo would behave better.

Breaking Glass Detector (1)

GrahamCox (741991) | about a year ago | (#43672985)

Puts me in mind of a breaking-glass detector my rather naive (in electronics terms) boss came up with in the early 1980s as a security device. Technology wasn't really up to FFTs or anything in those days, so it had two filters, one to detect the low frequency 'thump' of whatever hit the glass, followed by the high frequency 'tinkle' of when the pieces hit the ground, after a short delay which was also considered. It did work given ideal conditions, but in practice was extremely unreliable. I wonder why?

Why naive? (1)

Viol8 (599362) | about a year ago | (#43673381)

Seems like a clever idea to me even if there was too much enviromental variability for it to succeed. Pressure mats and other affordable 80s style security devices weren't exactly reliable or hard to foil either.

Presumably you had a far better solution so why not fill us in about it?

Re:Breaking Glass Detector (1)

stoploss (2842505) | about a year ago | (#43673389)

Okay, I'll bite: what was wrong with the design?

Poor filter design (though surely it wasn't mistakenly set up with a high/low-pass filter in a bandpass arrangement)? Flawed assumptions about the "thump" followed by a high frequency "tinkle" when glass breaks? Difficulty constructing a state machine for these conditions? Poor/nonlinear mic response over the frequency range required?

Was it subject solely to false negatives or were false positives a factor as well?

mod d03n (-1)

Anonymous Coward | about a year ago | (#43673183)

Mire of decay, risk looking even 'superior' machine. It's going, If you don't mutated testicle of Java IRC client win out; either the maggot, vomit, shit

Clapper Overkill (0)

Anonymous Coward | about a year ago | (#43673421)

Yay, an over engineered Clapper that has a million more ways for a false trigger...

Oblig (1)

ThatsNotPudding (1045640) | about a year ago | (#43673433)

/reads article, whistles appreciatively.

/power goes out

did you think about disabled that can't whistle? (0)

Anonymous Coward | about a year ago | (#43673449)

I'm joking. But everyone is concerned about accessibility these days. I had Bell's Palsy and now can't whistle.

Already been done... (1)

GregC63 (1564363) | about a year ago | (#43673575)

You might want to check this out at the patent office first, there was a device I remember from the late 70's, early 80's very similar to the "Clapper" called "The Whistle Switch" that did exactly the same thing.

You plugged it in the outlet then plugged whatever appliance (typically a lamp) you wanted to turn on or off. It came with a little whistle that had a squeeze bulb on it that you would produce a high pitched whistle and toggle the device on and off.

You could also reproduce tone whistling with your mouth. Here is a vintage site that has one.

http://www.etsy.com/listing/91099093/vintage-whistle-switch?utm_source=google&utm_medium=product_listing_promoted&utm_campaign=vintage_mid&gclid=CMaxzOv9iLcCFYyF6wodxR0A1A [etsy.com]

Some people told me that my latest project might i (0)

Anonymous Coward | about a year ago | (#43673681)

Some people were quite wrong.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?