A free program for Android, by Rakta Tech.

Microphone Blocker – Mic Guard is a free app that blocks access to the microphone on your Android phone or tablet. The app works as an ideal solution to a very common problem. Many apps on the market try to use the microphone on your device to implement various functions. Some use the microphone for audio recording, while others use it to detect when you have spoken or made a call. In most cases, the microphone on your device is used to capture audio in the form of a sound wave.

Microphone Blocker – Mic Guard solves the problem by preventing access to the microphone. The app does not interfere with the normal operation of your device. It does not affect the quality of sound or the ability to make a call or an audio recording.

The app can be easily installed on your device, and it does not require root access or a specific operating system. The app is compatible with Android 4.0 or higher.