I need to build one that can be used outdoors.
Where can I find the schematics for this kind of circuits?
You can find a million different circuits online with a simple google search. The problem is you haven’t given any useful info about what it is you need. You want to generate a sound outside? Cool, I can point you to a circuit that you can’t hear from five feet away, but it meets your criteria because it was used “outside” and produced a garbled mess that still counts as a “sound”.
If you want help, you need to provide an idea of how much power needs to be generated, how many speakers you are driving, how clear you need the sound to be (and this distinction will be quite different depending on if you are generating a tone, music, voice, etc), how FAR away you want to hear the sound, and it wouldn’t hurt to show what you’ve already tried and how that varied from what you were expecting. If you plan to leave this outside long-term, then you should describe what your plan is for weather-proofing as that will have an effect out the output also. And since I don’t know jack about analog circuits, there’s probably more information required to build what you need.
Sorry, even if you want nothing more than a siren sound there’s nothing easy about your question.
I edited the post and added information.
The Adafruit solution below looks like a good suggestion if you need something pre-built. However if you’re interested in the DIY approch, you could also take a look at something like https://www.ebay.com/itm/404254884824
Pair this with an arduino nano and you’ll have a fairly compact programmable device (I assume for your purposes, you only need mono output). You could also add a lithium-ion battery, solar panel, and charge controller to make something completely self-contained, but that would take a bit more work to figure out how much power is required to play each recording, and how many times per day you want to be able to play them so you can have enough battery power and a large enough solar panel to keep them charged.
Also remember to put your speakers in a box as that will make a huge difference in the volume of the sound being played.
Like single frequencies/tones (beeps, boops)? Or more complex sounds (dog barking, voice)? A little more specifics about your project would help us give better info.
Please read the post again; I’ve edited it.
It sounds like you are looking for something like this: https://www.adafruit.com/product/2210
If you look around the site, there are lots of helpful tutorials to get you started with it and also help you adapt it to your needs. They also sell most of the extra parts you would need. For example you could add this to make it motion triggered. Their parts aren’t the cheapest tho, you are paying for the ease of use, excellent documentation, and tutorials. If you’re crafty, most of it should be salvageable from e-waste.
Before you try a complex diy solution you already have tried a easy solution, like “Animation away” from “Royal Gardeneer” or similar gadgets which create a ultrasound siren?!? And if this 20,- EUR/USD Gadget is not working for these dogs, you could open it and use 99% of the device to add an mp3-circuit-board.
Power supply, speaker, case, and however you want to trigger, generate, and terminate the sound. For simple sound, and oscillator circuit and specific logic. More complex they use to sell sound chips. These days you could use a raspberry pi or even an old cell phone and program it. There is probably even off the shelf stuff you could link with Wi-Fi, z-wave, or zigbee these days.
I added information on the post
Keep in mind z-wave and zigbee devices can be low power. Plus they form a mesh network so can have fairly large total area. The controller though might not be that low power.
Dogs … they may be leaving based in small not sound. Also sound… the higher energy part of that is the actual speaker. Other the thing to think about too. Ultrasound beyond human hearing. Dogs do not like.
The other question is how do you plan on triggering the sound. That seems a bit more complex unless it is just timer based or you pushing a button.
Timer based would be fine.
OK. So I think you have your answer. Case, board, battery, timer circuit, tone generator. Look these up on the web. Lot of them will be based on the 555 timer chip. A common electronics store is Jameco and Newark. There are other sound chips too but I am not familiar with the numbers. Simple oscillators do not actually need an IC, could probably just be discrete. Keep in mind to electronics do have temperature ranges, performance of whatever you design will have to be tested at different temperatures.
More realistic sounds, I think that gets harder fast. To do that you’d have to in the end record sounds into a PROM and read it out though a DtoA. Or use an SBC and program it.
Historically there were sound generator chips like: https://en.wikipedia.org/wiki/Texas_Instruments_SN76477 . Not sure if these are even made any more. Again the sounds were crude.
