Making Windshield Wipers Rock To The Beat

When you’re driving around, you might occasionally notice your indicators or windscreen wipers sync up fortuitously with the music. [Cranktown City] wanted to ensure his wipers would always match the beat, however, and set about making it so. 

After disassembling the wiper motor, The original controller PCB is ripped up, used solely for its home position contacts that help determine the position of the wipers. The battered board is then drilled out to fit a rotary encoder to track the wipers throughout their full motion.

An Arduino is used to read the signal coming from the wiper stalk in order to know what mode the wipers should be in, and uses a motor controller to drive the wipers thusly. It also reads the encoder and home position contacts to track the wiper movement, and uses a proportional controller to control the wiper position. An MSGEQ7 spectrum analyzer is used to track the bass of the music to determine the beat to sync up to.

The final build does work, though in a different way to other designs we’ve seen. Rather than measuring BPM and syncing on a four-to-the-floor pulse, it simply tracks the lower band output and thus is more reactive to funky drum beats.

It’s a fun way to modify your car, even if it did require cutting a chunk out of the hood. If you’re cooking up your own cheeky automotive hacks, be sure to drop us a line. Video after the break.

10 thoughts on “Making Windshield Wipers Rock To The Beat

  1. Congrats to Cranktown City on the successful build.

    Check out this 2019 Hackaday feature for a more robust version of this idea:

    The basic approach to beat detection is to watch for a certain FFT bin to rise above a predetermined threshold and say that’s a “beat” – however you’ll quickly find this only works for the most basic of rock songs with simple obvious beats. Other genres, and music with double beats or triple beats or skipped beats (ex: Queen’s “we will rock you”), just won’t work. Instead the more robust project above uses an AI beat detection scheme that can deal correctly with most music (yes including punk, metal, etc)

    Also there’s no need to drill out the motor casing and install an encoder. The wiper motors already have a park switch, so the project above uses a PLL scheme to synchronize the wipers to the beat without any modifications to the wiper motor.

    Hope others find this interesting,

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