One Button Megaphone is a simple and straightforward megaphone app that allows you to use your phone as a bullhorn. With this app, you can easily make loud announcements using your phone's mic and an external speaker, whether it's wired or Bluetooth-connected.

The app is easy to use, with just one button to activate the megaphone feature. No additional AV equipment is required, making it a convenient tool for any situation that requires a loud voice projection. However, it is important to note that the app warns you if your device isn't connected to an external speaker. If you believe it is connected and still receive this warning, you can disable it by going into the settings and selecting the "Remove external speaker check" checkbox. Do note that this is not recommended, as it can cause horrible feedback from the internal phone speaker.