Sound level autonomous wi-fi sensor (Noise detector)

Hello gurus!

I’m thinking about building a sound level autonomous sensor, that will send data to my server using wi-fi and looking for your advice.

The device should not be very precise on the sound level - I’m ok if it will only say if the sound/noize level around it is “low/med/high” or even boolean “sound/~no sound”. Also, it should not be always streaming data, rather it should be in deep-sleep mode all the time, wake up once every ~30secs and send data over wifi (simple POST request) if the sound/noise level is med/high.

Other requirements include:

  • Size. The device should not be larger than a typical matches box
  • Endurance. The device should work from a battery ~1 month

I imagine the device would be consisting of sound sensor + microcontroller with wi-fi transmitter + battery. I’ve googled the topic And need your advice on the following:

  • What type/model of sound sensor would you recommend? Or maybe I should create one from a microphone considering size and endurance restrictions I have
  • What model of microcontroller would you recommend considering size&endurance restrictions and potential connection with sound sensor. Right now I use ESP8266, but it doesn’t seem to fit any of my restrictions :slight_smile:
  • Taking into account size restrictions I’m thinking about using CR2477 coin cell battery(ies). Maybe you have some better suggestions

Your feedback and advice is much appreciated!
Thank you in advance!

ESP8266 is the obvious choice considering your WiFi requirements. That does likely exclude the use of a coin cell, as WiFi transmissions require more power (some 100 mA) than such a small battery can supply (20-30 mA). It does have good sleep functions, so a month on battery power should be no problem.

Sound sensors: there are lots of simple modules out there that can produce digital or analog outputs.

wvmarle:
ESP8266 is the obvious choice considering your WiFi requirements. That does likely exclude the use of a coin cell, as WiFi transmissions require more power (some 100 mA) than such a small battery can supply (20-30 mA). It does have good sleep functions, so a month on battery power should be no problem.

Sound sensors: there are lots of simple modules out there that can produce digital or analog outputs.

wvmarle, thanks! Are there any alternatives to ESP8266 since as you mentioned it kills all the endurance, which is crucial for me.

The ESP8266 can operate at really low power. That's not the problem. It's the WiFi radio that requires the high currents. No way around that short of switching to an entirely different kind of radio such as Bluetooth, or even BLE, protocols that have been designed to be low power.

Got it! Thanks!