AVR Freaks

I assume you have checked whether this is legal in the intended market(s) ... ?

Your requirement is not clear - you talk about "FACTORY RELAY" and "FACTORY RELAY HORN"

As Torby says, the frequency of the horn itself is fixed - it cannot be changed.

So you are going to have to replace the actual horn - the sound-producing device - not just the relay.

In fact, there is no reason to change the relay.

No, it does not necessarily mean that.

These were quite common over here 40 years ago - before they were banned - and they never used microcontrollers!

But perhaps Bill Bailley could help you out: https://www.youtube.com/watch?v=...

Like this:

https://www.amazon.co.uk/Dixie-D...

Not a microcontroller in sight!!

Modern police cars etc have siren sounds that vary a lot. I suppose that means the system consists of a speaker (megaphone type) and some kind of synthesizer? Obtain one of those (legally!() and hack it?

Ok, this sums it up

+1

The horn mechanically cannot be pulsed to make notes very well either.

As noted in prior posts there is also the legal side of altering the horn as the very nature is to 'alert' others for whatever reason.  The horn is designed to be annoying and IIRC the frequencies used are specific to over come environmental obstacles(air resistance, closed car interiors, noise reduction interiors, loud radios etc.)  Altering one, and getting into an accident that could have been prevented with a properly functioning horn Blah Blah Blah.

As also noted there are already pre-made musical horn kits that are far better suited for this sort of thing.

Jim

PLS GUYS, BE MORE SERIOUS OBOUT THIS!!!!!!!!

The user name doesn't help, it's just one letter different from undies.......mutande vs mutante....of course I read it wrong the first time around.

Really? 

From your OP:

First sentence.

THEN under your specs:

You mention the 200 degree requirement, along with replacing the the FACTORY RELAY HORN et al.

Lastly:

Sure sounds like you are looking for a complete kit.

And if you read the posts, you HAVE been given ideas on gear thats already out there to in fact make some of these sounds you are looking for, and at the same time, throwing caution into the wind about this little endeavour as well.

Jim

or simply buy a car and try to play with the horn.

This will get you FINED in Australia unless it's an emergency and you don't want musical anything, just a blast to warn someone (ie someone crossing the road with headphones on), just like the manufacturer designed it. Even sounding the horn in anger can get you fined for road rage!

But if one is at school then these kind of horns could be appealing I guess.

To be fair, what (s)he actually wrote was:

Illegal or not of of alterring the horn is not a a bussiness of an electronic forum

By which I guess (s)he means, "the legality or otherwise of altering the horn is not the business of an electronic forum"

EDIT

My thoughts exactly!

Illegal or not of of alterring the horn is not a a bussiness of an electronic forum,

On the contrary.  You're asking for free help from private individuals giving their time to a public forum.  What could possibly compel us to help you do something illegal?

Good luck with your project.

About 25 years ago, I build a novelty horn for my Vauxhall Carlton(just to set the period...).

It had a CMOS counter(CD4040 IIRC) for address generation, an EPROM, a DAC and a BTL amplifier chip driving a small horn speaker.

It also had a simple 7805 regulator for the "logic".

The whole thing was wired to the horn relay, instead of the conventional horn, and would have looped ad-infinitum if you'd have kept your hand on the horn.

The audio was a duck quacking, taken from a BBC sound effects compilation, with a sheep bleating at the end for good measure.

My theory was that I only ever used the horn if I saw someone I knew, and with a horn like that the hootee would immediately know who was hooting them. Also, my nephews thought I was the coolest dude on the planet(which happens to be true, as it turn out).

The whole thing was assembled on perf board fixed to a piece of wood, and mounted under the bonnet/hood with no protection against the elements whatsoever.

Despite all the stuff you read about cars being hostile environments for electronics, it worked perfectly for two or three years until I stupidly ran low on oil and seized the engine, and ended up dumping the car near Cambridge.

It was not, however, considered legal for the purposes of the MOT, which is our annual safety test, so I would have to reconnect the factory horn once a year.

"I read decades ago that someone in England figured out that signs with lower case letters could be read at a greater distance than when all upper case was used, because the ascenders and descenders gave the words a shape that upper case letters did not. "

That's interesting, and makes sense.

So I shall overlook your somewhat ridiculous implication that there could be a right or a wrong side of the road to drive on.

Just as soon as you get rid of all fuel-wasting four-way stops and replace with mini-roundabouts.

It always seems to me that the modern, electronic "wail" sirens on our emergency vehicles are never as loud as the old "Deee-Daah" twin-tone air horns.

Or maybe it's just that the air horns were at a more "alerting" frequency; and/or the abrupt "Deee-Daah" transition was more "alerting" ... ?

I believe the new siren sounds have been researched and designed to be better in some way, although I seem to have forgotten the details.

I think you are right, just re-read the 1st post.

I suppose there is a chance of producing other tones(and I did allude to this in post #22), but it would be a bit hit and miss with a conventional car horn, which, unless things have changed dramatically over the past 50 years, are simple "vibrator" (stop that sniggering at the back there..) devices with a diaphragm(I said stop it!) attached. You would, I suspect, have to switch the power at a rate higher than the natural period of oscillation, so that the "points" never got a chance to open.

Anyway, maybe Mutante will come back and tell us how he gets on.

 ... and, hopefully, not too much bull !

They are, AFAIK. At least on newish Volvos..

Snigger... ;-)