Airbags, And How Mercedes-Benz Hacked Your Hearing

October 6, 2025 by Lewin Day 42 Comments

Airbags are an incredibly important piece of automotive safety gear. They’re also terrifying—given that they’re effectively small pyrotechnic devices that are aimed directly at your face and chest. Myths have pervaded that they “kill more people than they save,” in part due a hilarious episode of The Simpsons. Despite this, they’re credited with saving tens of thousands of lives over the years by cushioning fleshy human bodies from heavy impacts and harsh decelerations.

While an airbag is generally there to help you, it can also hurt you in regular operation. The immense sound pressure generated when an airbag fires is not exactly friendly to your ears. However, engineers at Mercedes-Benz have found a neat workaround to protect your hearing from the explosive report of these safety devices. It’s a nifty hack that takes advantage of an existing feature of the human body. Let’s explore how air bags work, why they’re so darn loud, and how that can be mitigated in the event of a crash.

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Generating Pink Noise

May 24, 2011 by Mike Szczys 9 Comments

[Miceuz] just finished his first surface mount electronics project. It’s a pink noise generator that is used for testing audio equipment (scroll down that link for the English version of his writeup).

Pink noise is somewhere in between red noise and white noise. Didn’t realize there were more colors than just white when it comes to noise? The benefit of testing with pink noise is that it the power of the audio signal is stable through each octave of sound – white noise increases in power with each additional octave which can damage the tweeters in a sound system.

The goal in this design was to build a noise generator that fit into an XLR connector. [Miceuz] started with an existing design, and altered it to suit his needs. Much like a condenser microphone, the pink noise generator uses phantom power instead of a standalone power source. For instance, the design he based this on required two 9v batteries. The size, the choice of case, and the absence of a battery all spell WIN for this project.