is there anyone can help me ??

[yak103]

Hi ....
I am wondering if someone can help me with my project ... actually i am planning to do sound recgonition circuit that store a special sound like police car alarm and recognize it within the circuit to control other devices ???

thanks

 

[HarveyH42]

Why? Does this involve illegal activities?

 

[yak103]

No ... actually I would lo help the police cars to cross the traffic light using their sound signal ..... making an intelligent traffic light ... this is my project ..

thanks

 

[akg]

so in what part you require help..?you didn't specify anything

 

[Tarsil]

Hi ....
I am wondering if someone can help me with my project ... actually i am planning to do sound recgonition circuit that store a special sound like police car alarm and recognize it within the circuit to control other devices ???

thanks

Use one from a phone with Voice Dialing function (like the old Nokia3310).
The idea is to use a low definition ADC, record the sound and let a uC to compare it (or parts of it) with incoming sound. That's how is made by Nokia (was told). The higher the uC speed, the higher the ADC definition and lower number of false alarm. I think u could implement this with a 16F877A uC if you're skiled enought in programing.
If u want it in real time then ....is more complicated.

 

[William At MyBlueRoom]

Many firetrucks use a strobe to control the traffic lights. An RF transponder or strobe light is more common than a sound signal.

https://en.wikipedia.org/wiki/Unusual_uses_of_traffic_lights

 

[HarveyH42]

In the United States, they use infrared strobed around 24kHz (if I remember right). The device is called a MIRT, do a search with Google and you should find a sight that details the construction, as well as several news stories about people getting arrested for using them. Seems that many of the busy intersection that have this kind of controller, also have cameras to catch redlight-runners...

 

[yak103]

thank you all for replying ... however i would like to tell you more about my project which is sometimes the police cars need to cross the traffic light safely without making any accedentes so my plane is making a circuit that recognizes the police car's alarm sound and converted into voltage to control the traffic light for example making the light red ... so wht compenents should i use to this circuit and to recognize this sound ?

how am gonna use the pulse code modulation ??

thanks

 

[HarveyH42]

**broken link removed**
Turns red lights to green. Full circuit, description, and legal penalties.

 

[kchriste]

Turns red lights to green. Full circuit, description, and legal penalties.

This really shows how stupid governments are. To put such a simple system in place that is just screaming to be hacked by someone with a 555 timer. You would have thought that they would have coded it somehow.
Even your TV remote has more security than these traffic light systems!
Sheesh!

 

[Roff]

**broken link removed**
Turns red lights to green. Full circuit, description, and legal penalties.

But if you're in an emergency vehicle, you want all lights to be red.

 

[philba]

the MIRT system is very old, they've (who ever they is) introduced a newer version that is supposedly encrypted but it's hard to replace the 10K+ units out there overnight. not to mention all the transmitters.

Note also that it is mostly lights at busy intersections which have them and these often also have cameras. anyone screwing with these is just asking to be a guest of the county.

actually ron, making the light red will cause people to stop and makes for congestion - people will go through green lights to get out of the way of an ambulance but most won't venture into an intersection with a red light showing.

 

[Roff]

actually ron, making the light red will cause people to stop and makes for congestion - people will go through green lights to get out of the way of an ambulance but most won't venture into an intersection with a red light showing.

Duhhh...

 

[HarveyH42]

I don't understand the importance of using sound to control the lights in your request. It would be very difficult to get the correct direction the police car is traveling, distance from the intersection, ect... from the siren. The government isn't likely to replace the existing system, unless yours is greatly superior to what's already in use. And finally, in my mind I see more ways to abuse such a circuit, than it being a benefit. It's your project though, and perhaps you invision aspects of this project that I am unable to realize, but I'm pretty sure that this isn't very productive, but who really knows. Our government wastes millions of dollars, almost daily...

 

[philba]

I have to agree with harvey. It's not going to be reliable.

If I were you, I'd try to figure out how to detect the flashing lights. That's probably the best passive approach. I'd also spend effort figuring out how to avoid false detection.

 

[HarveyH42]

If the MIRT system can easily be hacked with some IR LEDs and a 555, think of how much easier a sound based system would be? Loud stereo and a CD recording?

 

[audioguru]

Barking dogs and squealing tires would change the lights to green, at the same time a police car was going through the intersection. CRASH!

Which type of sound? The 2-tones in Europe or the siren in North America?

These two foxes can make the sound of a European 2-tone:

 

[Hero999]

I've heard that some of the traffic lights are sensitive to the strobes on emergency vehicles any flashing your headlighs at them at the right frequency is supposed to work. I haven't tried this though as it might be an offence.

 

[audioguru]

Are your headlights strobes that can completely turn on and off very quickly like strobes???
Are your headlights anywhere near as bright as strobes???
Aren't your headlights shining ahead on the ground, not up at the sensor???

If you could flash them so quickly then they would just be a little dimmed.

 

[Nigel Goodwin]

I've heard that some of the traffic lights are sensitive to the strobes on emergency vehicles any flashing your headlighs at them at the right frequency is supposed to work. I haven't tried this though as it might be an offence.

Flashing headlights at traffic lights has long been a myth, as far as I'm aware there's no traffic light over ride for emergency vehicles in the UK? - they simply go through at red - relying on all the traffic stopping (which it does).