Car Alert Emergency Safety System High School Project Help

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wbrown008

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I'm a new-comer to the world of radio's and I need some help. I'm in high-school and working on a senior project. Basically our idea is a safety system for automobiles that cuts out the car radio when there is an emergency vehicle in in the area and inserts an emergency broadcast. The device would be something as simple as a box that a civilian could stick in their trunk. The emergency vehicle would also have a transmitter. I actually have to build this so any information would be greatly appreciated. My main questions are, what frequencies would I use(public?), Where do I start, and how might I build this (kits?). Thanks in advance for any and all help.
 

SAR923

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There's a number of issues I see. The first is that you wouldn't need to have anything mounted in the civilian's car. An emergency vehicle could be equipped with a wide band, low power transmitter that covered the entire AM and FM band. The transmitter could then transmit a warning that would override any AM or FM transmission being listened to by the civilian.

That being said, the FCC would have to approve of such a plan, something that I don't think has ever been done. You'd have to install a transmitter in every emergency vehicle in the country, which is not a cheap proposition. Having citizens install something that would receive a broadcast on a certain frequency is a non-starter. Who would pay for it, where would it be mounted (if it's in the trunk, how will they hear it and what about vehicles with no trunk), what kind of antenna would it use, and how would they know if it's working? Lastly, how many of your friends listen to the radio at all compared to CD's or MP3's? How would any system override this? How would this system work if the radio was not on at all?

It's an interesting idea but I think you should revisit some of the questions I've posed to see if this idea is really workable.
 
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N_Jay

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I'm a new-comer to the world of radio's and I need some help. I'm in high-school and working on a senior project. Basically our idea is a safety system for automobiles that cuts out the car radio when there is an emergency vehicle in in the area and inserts an emergency broadcast. The device would be something as simple as a box that a civilian could stick in their trunk. The emergency vehicle would also have a transmitter. I actually have to build this so any information would be greatly appreciated. My main questions are, what frequencies would I use(public?), Where do I start, and how might I build this (kits?). Thanks in advance for any and all help.
Sounds like an interesting project, but you may have bitten off more then you can chew.

Radio is a hard medium to control.
Any RF based system will probably have an 5x to 10x difference in range, meaning if you want it to go off at 1 mile (hypothetically) you could be triggering at anything from 0.1 mile to 10 miles.

Have you thought about optical looking for red/blue/white blinking lights?
 

donc13

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I'm a new-comer to the world of radio's and I need some help. I'm in high-school and working on a senior project. Basically our idea is a safety system for automobiles that cuts out the car radio when there is an emergency vehicle in in the area and inserts an emergency broadcast. The device would be something as simple as a box that a civilian could stick in their trunk. The emergency vehicle would also have a transmitter. I actually have to build this so any information would be greatly appreciated. My main questions are, what frequencies would I use(public?), Where do I start, and how might I build this (kits?). Thanks in advance for any and all help.
Like others have said...good idea but the implementation on a large scale would require FCC action.

However, for a school project only, it would still be a bit complex. There's a thousand ways to do it but all would require a modification to the car radio if you wanted to 'turn it off'. Something that would receive the signal, cut the power to the car radio, and then amplify a signal and put over the speakers.

There's lots of remote control devices (such as Radio Controled model airplanes, or a wireless microphone) that could be adapted for that use.

Were I doing it...for the project...I'd build a transmitter and a receiver and just put them near each other in a classroom and demonstrate the concept of how it'd work. I'd not actually modify anyone's car...even yours.

;-0)
 

Freq_n_Hertz

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ITs a high school senior project!

Wbrown008,
I commend you for your creative thought and believe you can probably complete this as a high school project.
I expect you have limited design experience in electronics so some challenges are ahead of you (and your team?). You've already shown some initiative in reaching out to forums for advice, you may want to seek some locally also.
That being said, I think you need to approach this from a little higher level in that you should probably use receivers and transmitters that are already designed and boxed up. You will need to then figure out how to get them to work in the function you desire.
You might consider using FRS radios (the little walkie-talkies), garage door openers, or some other remote control device. You can then figure out how to get that device to actuate a relay or switch to control the radio, breaking the +12 power circuit would do it. You could also put relays in the speaker wiring but you may need more relays. Some car radios have a mute line already that is supposed to operate with a cell phone.
I think your teacher would be suitably impressed if you gave him a ride in your car and your friend drove by in his car and shut off your radio!

have fun!
 

kb2vxa

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To put it simply it's a good idea but impractical to implement. You'll get higher marks if you follow the rule "necessity is the mother of invention". If it's not needed it's useless unless you can get Billy May or Ron Popiel to market it to fools. Now think of something we really need, is simple but effective and can be used in a practical manner. Now what would fill that need? Develop your idea, good luck and good marks.

Now here's an idea, a siren that can shatter concrete at 100yds should get their attention. (;->)
 

Freq_n_Hertz

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emergency vehicles have IR transmitters

Wbrown008,
Too many ney-sayers on these forums. If your passionate about it then you should pursue it.

Here's another idea, some cities have IR transmitters in there vehicles to control traffic lights. A compatible IR receiver could also be used to shut down the radio by detecting the same signal.
Link to wiki on device - http://en.wikipedia.org/wiki/Traffic_signal_preemption
 

jdebona

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Too many ney-sayers on these forums. If your passionate about it then you should pursue it.
No kidding. I'm dissapointed in most of the posts here. Here's a young person in high school with a creative idea looking for feedback in one of the best places in the world for such feedback. He never said he was banking his life savings and entire career on the project.

I think this is a GREAT idea for a school project. Of course there are FCC/government/legal concerns. Of course there are implementation issues. Of course there are questions about who would fund it (it usually ends up being a burden carried by the consumer one way or another anyway). I would think merely acknowledging that those obstacles exist would go a long way toward getting a good grade from a reasonable teacher. High school is about teaching thought processes and basic life skills, not solving all the worlds problems. Okay, I'll get off my soapbox now.

Personally, I wouldn't want the government mandating that every radio or car manufactured after Jan. 1, 2XXX, have this proposed device, but there are more than a few government officials who would gladly lend their ear to some sort of proposal. It doesn't have to be mandated anyway. You could argue there is a potential market of safety-concious drivers who might want it. There is certainly a problem to be solved from the public safety perspective. This alternative solution was just posted on Fox News today: http://www.foxnews.com/wires/2008Nov12/0,4670,HowlerSirens,00.html. In my opinion your device is more flexible and could also have uses at railroad crossings, construction sites, rock slides, drawbridges, accident scenes, roads prone to flooding, etc.

Rather than modifying an in-car radio and taking the teacher for a ride, why not just go through your old parts in the garage or pick up some off E-Bay? For a good classroom demonstration of your concept, you would just need a 12V power supply, a cheapie radio, and a set of speakers in addition to your invention. It's just a prototype. Your parts could be packaged in a project box from Frys or Radio Shack or even a shoebox for that matter. I like the idea of using some pre-made transmitter like an FRS radio, or even a kid's walkie talkie. Surely it doesn't have to operate on the exact frequency of the "officially" proposed device. Also consider infrared or something more directional (could be pointed at cars in the way rather than just a "broadcast"). As other posters mentioned people obviously listen to so many other things besides AM/FM like iPods, XM, movies, etc., so your device would need to be inserted near the sound output of the radio. Also consider many radios have line-level outputs connected to an external amplifier so delays and volume will need to be considered. I can't help with more technical details, but you obviously need a receiver to trip some sort of interrupt like a DPDT relay to play your alarm or "recorded" message. A simple mp3 player or casette player enclosed in your magic box might suffice for your prototype. The whole thing minus an antenna could be miniaturized with today's technology to sit in the palm of your hand, but your prototype shouldn't have to be that small or even pretty for that matter.

Good luck!
 

unitcharlie

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No kidding. I'm dissapointed in most of the posts here. Here's a young person in high school with a creative idea looking for feedback in one of the best places in the world for such feedback. He never said he was banking his life savings and entire career on the project.
These aren't nay-sayers, they are giving this fellow honest, real-life feedback.... Personally, I think the problem is more basic and is something he could pursue.... making driver's ed a requirement for a driver's license for anyone under 18.... Also speaking personally, I don't want anything else put into my POS car than needs to be there.... too much runs thru the car's computer that I can't control as it is, all I need is another ON-OFF switch that someone else controls in my vehicle....
As any fighter pilot knows, keeping your head in the cockpit kills.
 
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Doesn't most new car radios have RDS (Radio Data System) capability already. RDS can be used to provide traffic information, emergency alerts and several other functions. Certain functions will pause your CD (if playing) turn up the volume so you can hear the alert. When I lived in Germany back in the early 90's it was used for traffic alerts and information.
 

roadranger

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Try this:

If an persuing patrol car is actively using radar as it is motiviating at code 3, you just need a detector of radar, to aid in disabling just the speakers, for a delayed amount of time. Simply by detecting radar, the audio goes away on it's own, and returns on it's own, seconds later.
 

kh8cg

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Despite this being a predominantly RF forum, you may want to consider an alternative method of achieving your desired results. Your stated goal seems to be enabling the driver to hear approaching emergency vehicles.

The basic problem that you want to overcome is that the sirens cannot be heard well from inside a car which was designed to keep outside noises attenuated, particularly if the car's sound system is cranked up, creating a masking effect.

Rather than utilizing RF, which adds a level of complexity which others have already pointed out, consider using what is already there: the sounds of the siren.

If you utilized a wind baffled microphone on the outside of the car, and fed that into an audio amplifier/filter/processor, you could construct a "siren detector". This device could then drive a switch configured to do whatever you desire to do with the car's stereo. You could even pipe in the outside sounds picked up by the microphone during the activation period.

With a bit of intelligent processing, the filter could effectively discriminate siren sounds from other sounds which you would not want triggering your device. There are obviously many siren sounds, but most fall within a limited range of frequencies, and are generally modulated in a repeating pattern. Your filter processing would take advantage of this.

Good luck with your project. It sounds like a worthwhile endeavor.

Kris
KH8CG
 

ampulman

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I'm a new-comer to the world of radio's and I need some help. I'm in high-school and working on a senior project. Basically our idea is a safety system for automobiles that cuts out the car radio when there is an emergency vehicle in in the area and inserts an emergency broadcast. The device would be something as simple as a box that a civilian could stick in their trunk. The emergency vehicle would also have a transmitter. I actually have to build this so any information would be greatly appreciated. My main questions are, what frequencies would I use(public?), Where do I start, and how might I build this (kits?). Thanks in advance for any and all help.
Years ago, I thought about this and thought about an easy solution:

Emergency vehicles would be equipped with dual transmitters/antennas; one for each of the common IF frequencies, e.g., 455 khz and 10.7 mhz. (or whatever is in use, today).

The antennas would be designed to cover a field of 90 degrees (or so) centered in the forward direction. Then, at will, the vehicle could trigger an announcement such as: Police vehicle traveling north on main approaching 2nd st. making left turn -- etc. The transmissions would swamp the receivers located forward of the emergency vehicle, leaving others out of the 'field of view' of the antennas unaffected.

I don't know if it would work, but would be easier than transmitting over a large slice of spectrum.

Amp
 

Paulsan

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Don't Escort radar detectors have a way of notifying you when there is construction or emergency vehicles nearby?
 
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N_Jay

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Don't Escort radar detectors have a way of notifying you when there is construction or emergency vehicles nearby?
That is based on a signal sent on the radar band. (I think it it at 10 GHz)
 

n8emr

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I though the big 3 makers already had something similar but never implemented it. It would mute a car radio when a public safety vehicle was in the area. Cam out about the time lots of folks started going to MP3 players. It wouldnt work with the millions who now use ipods and non-radio devices.
 
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similiar technology exists like Severe WX anouncements on WX radios or Scanners. Like on scanners if feature turned on would cut over to the severe weather broadcast.
 

digitalanalog

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I say go for it.

Their are allot of Good idea's on what would be involved posted in this thread.

All the NAY-SAYERS, would like nothing more then to see something like this NOT work, Just so they could say "They Told You So".

It is possible, but much work will be involved.
Good Luck.
 
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RLADY22

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Great Thought

I am glad to see that someone is teaching our children to think...often, in electronics especially, what may be technically posiblile may not be politically(fcc)or economically possible..that said...are you really looking to control the output of the radio etc...or perhaps just the out put of the item...be it cd, radio or other...perhaps the answer lies in the speakers..I know that at some point there were cellullar accesories that would either "turn down"or "turn off"-via speakers(for lack of a better word...the comercial radio/stereo when there was an incpoming call...my back round is more commercial two way...but this might be an option...and always remember what is not "possible" today may be next years must have....good luck
 
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