I am looking for a circuit to amplify a tone from my arduino (a beep) to be heard at 200meters. I have tried an lm386 an a 4ohm speaker but its max range is about enough. Can you suggest another type of speaker or a piezo buzzer? also maybe another amp?
For 200 meters I would not make something myself.
Try google image search for: car horn alarm
Or search: Alarm Siren Speaker
Don't forget that sound diminishes as the square of the distance from the source, because it's spreading out over the surface of a sphere...
So to make something the same at 200m as at say 1, you want it 40 000 times as loud. Anyone who is unfortunate enough to be close to the thing is going to get their eardrums mangled.
I don't want it to be as loud as a loundspeaker at 200m but rather be aware thay something is beeping toward that direction.
be aware thay something is beeping toward that direction
For it to sound like it's "beeping toward" a point, to me that's the same as sounding like a beep at that point. Your subject line even says "beeping at 200m". The power at 200m is 1/40000 of what it is at 1m, so therefore to have 1 unit at 200m it has to be 40000 units at the source.
I don't think you can escape that....
(Unless I'm remembering Physics1 wrongly. Possible, it's almost 40y ago.)
Whether what you create as a sound will be heard will depend on several things:
The ambient sound - gonna be hard to hear anything 200m away in a city, maybe more possible in a forest.
The height above ground of your source.
The frequency of your sound - some frequencies seem to carry better than other.
http://www.mpja.com/6-12VDC-Dual-Sound-Siren/productinfo/18678%20SU/
How directional of a speaker you use - plain flat faced speaker vs a directional horn speaker for instance.
http://www.mpja.com/5-X-8-Indoor_Outdoor-Speaker/productinfo/6244%20SP/
Desribe your environment more.
what am trying to do is something like this DT Systems BTB-800 Double Beep Baritone Beeper Collar. $99.95 (Save $25.04) FREE Shipping US48
basically its beeps so you know where ur hunting dog is, in a forest or high bush area.
I am using a tweeter speaker and a 1w amp and its not loud enough. Maybe the cone on collar above makes the sound directional and therefor louder? any diy way of making one?
If you use a loud tone with a square signal, it produces a lot of high frequencies. The dog can hear all those high frequencies even if you don't. I would call that crualty to animals.
Perhaps the manufacturer of the beeping collars have tested it and have engineered it in a way that it won't cause discomfort for the dog. But I think it is best for the dog, not to use those at all.
Would 2 gps modules, transmitter and receiver be an idea ? The dog won't be bothered by the noise, You'll be able to know where you both are and your dog won't alarm the wildlife more as needed...
By adding a compass module, ring of leds and perhaps a few leds to show distance, one look could be enough to know where your dog is.
dogs hearing range is from 40hz to 60khz, i am using a ~4khz tone (i use the tone()). as i understand the cone makes the sound directional and therefor points away from the dog, therefor the dog receives a lot less db. Any idea how the "cone" makes the sound directional? or how it can be done diy?
The gps idea is good however a little expensive and probably not practical as the trainer would have to look constantly at a device while trying to exercise the dog
The Arduino tone() produces a square wave, not a sine wave. That is why I wrote about the higher frequencies.
for just a simple beep, does it make a difference?
It is not a simple beep, it is a loud beep. And yes, it makes a difference.
which is better? square wave or sine?
You would be doing quite well to hear a loud car or truck horn from 200 metres away ( depending on the temperature and other things ). If I put a loud car horn next to your head and activate it, you will feel uncomfortable even if the horn is pointing away from your head. So will the dog. I don't think you will succeed in making this plan work.
You could use a -very- small capacitor to change square wave edges to sawtooth.
Just how small though, I am not the person to say.
Cheap 200x audio amp (they have a 20x too) that uses an LM386 chip:
http://www.lctech-inc.com/Hardware/Detail.aspx?id=f298dfcb-b19f-4318-9169-51a2bba26b6c
I haven't tested one yet, just got 2 of each.