Today’s phone microphones are perfectly adept at picking up sound in all sorts of conditions, and they’re backed by all kinds of processing techniques to filter out noise and capture clean audio. [mcore1976] has been working on a device to jam phone microphones that might be listening in, however, countering fancy processing techniques in turn. 

The build uses a microcontroller brain to control an array of ultrasonic transducers. [mcore1976] has created many revisions of the project, each time improving its ability to jam microphones in modern hardware. The latest revision uses an RP2040 microcontroller and a MOSFET drive stage to control 20-80 ultrasonic transducers. They’re driven with a PWM signal generated from the RP2040 itself. The signal output is specifically modulated to try and confuse the automatic gain control systems used in many modern phones in order to make it difficult for them to record clear audio when the jammer is running. As [mcore1976] demonstrates with an iPhone 17, his voice is completely lost amidst unintelligible garbled noise while the jammer is switched on.

It’s a niche idea, and perhaps most interesting because it affects phone microphones while being largely inaudible to the human ear. We’ve featured other interesting jamming devices of late, too. Video after the break.

今天的手机麦克风在各种条件下都能完美地捕捉声音，并且它们通过各种处理技术来过滤噪音、捕获清晰的音频。[mcore1976] 一直在研究一种设备来干扰可能正在偷听的手机麦克风，然而，反过来对抗那些花哨的处理技术。

该装置使用一个微控制器大脑来控制一组超声波换能器。[mcore1976] 已经制作了该项目的多个版本，每次都在提高其干扰现代硬件麦克风的能力。最新版本使用 RP2040 微控制器和 MOSFET 驱动级来控制 20-80 个超声波换能器。它们由 RP2040 自身生成的 PWM 信号驱动。信号输出经过专门调制，试图迷惑许多现代手机中使用的自动增益控制系统，从而使它们在干扰器运行时难以录制清晰的音频。正如 [mcore1976] 用 iPhone 17 演示的那样，当干扰器打开时，他的声音完全消失在难以理解的杂乱噪音中。

这是一个小众的想法，也许最有趣的是，它会影响手机麦克风，同时对人耳来说基本听不见。我们最近也介绍过其他有趣的干扰设备。 视频在休息之后。