Chirpr

Chirpr is a radio-free acoustic-link messenger. Instead of using radio such as wi-fi, bluetooth or cell network it uses the device's speaker and microphone to transmit your message using acoustic chirps. You can send text-based messages to nearby friends using sound. This is a demonstration of how acoustic modems operate.

It's safe to download Chirpr. Whimsical Otter has developed this application that lies within the Communication category. Over 100 users downloaded and installed the app and the most recent release was on Dec 6, 2018.

The average score for Chirpr is 3.6 on Google Play. There are ads in this application. It's free of charge to get the installer of Chirpr, also, you can have a look at users' reviews on Droid Informer. The app works fine on Android 7.0 and above.