Let's try here.
I want to create a product that works like this:
1. Place a device with a microphone at a location.
2. Sound over a specific level will trigger the device.
3. The device will communicate to a smartphone app through bluetooth or wifi.
I know how to write an app, but know nothing about this kind of hardware. Should I buy the components and mount it myself (and on what?) or do you think I could buy this device somewhere? Maximum price for the hardware would be around 30 dollars or so.
As you see, I'm in the dark here. Would much appreciate if you pointed me in the right direction.