Over engineering windshield wipers to sync to music

In the late 90s, Volkswagen aired a series of awesome television advertisements that won a few awards relevant to those in advertising circles. One of these ads was titled Synchronicity and showed a VW Jetta’s windshield wipers (among other things) syncing to music as the car drove down a rainy alley. [ch00f] thought beat tracking wipers would make for a great project, and we love the sheer amount of engineering that went into this build.

The build began with [ch00f] taking apart his wiper motor to get some specifics for his build. Ideally, a rotary encoder would be very useful for this project, but designing a durable encoder would be a pain anyway. [ch00f] had to settle with the ‘parking pins’ on the wiper gear motor that allow the wipers to be driven in intermittent mode.

[ch00f] spent a great deal of time writing code that would guarantee a constant wiper speed, but that didn’t solve the problem of phase, or having the wipers begin or end their cycle on the beat. This problem was somewhat solved (as you can see in the video after the break) by using a feed forward system – basically, the software would predict the change in phase needed and correct it by changing the speed.

The build still isn’t perfect, although that’s mainly due to the placement of wiper parking switch on the wiper motor. [ch00f] plans on spending a little more time correcting the wiper speed/phase control with software, but what he’s got now is still very impressive.

42 thoughts on “Over engineering windshield wipers to sync to music

  1. Insert nerdgasm here.

    Why do this? Because we can.

    We need hacker awards so we can bestow honor on guys like this.

  2. But pressing a button is way too cumbersome. There’s open beat detection code, there should be fast enough µCs to run it. Attach a microphone or the radio’s line out, and don’t tell anybody about it. It’s such a subtle effect, would feel like magic (“you’re tricked when somebody puts in more effort than you could imagine”)

      1. Awesome hack, ch00f! Slight nitpick, Gnarls Barkley’s “Crazy” is 112 bpm, it looked like you were tapping at about half that :)

  3. A question th the psychologists out there…

    What immersive effect would this contribute to – when using ‘aggressive’ or ‘calm’ music?

    Would the driver respond to the immersion effect of combined ‘music & visual cues’ in a way that is greater or lesser than ‘driving music’ alone.

    This may have the potential to create more aggressive(Angry) / focussed(Competitive) driving, or less-so (Camry!).

    nonetheless, I find the idea intriguing.

    1. You’re not the only one. Try watching the video without the music. You literally see nothing different about the wiper speed.

  4. Next addition after you get this to work: a rain detector connected to the CD player, to change to a faster song automatically when it rains harder :-)

  5. In my day we had AM radio that faded in and out between the buildings.

    And we liked it that way!

    //kids today and their ADHD need for round the clock crappy music//

    1. “Through the fire and flames” would literally result in the wiper motors catching on fire ;)

      I do have to say as a petrolhead, this is definitely a fun hack to the car, well done ch00f :)

  6. This is neat. I’d try to sync the turn signals as well… but making sure to subdivide the beat to keep it street-legal regardless of tempo (i.e. blink every X beats if tempo is too fast, or add Y blinks inbetween if it’s too slow).

    1. For optimum fun you should instead make the turn signal stagger or wander about the acceptable flash rate range.

  7. youve given me very very very bad ideas,

    driving+racing+music+rain

    hmm, intercepting ALL the accessory (wipers, lights, other lights, rear wiper, AND HORN!) signals all at once and drive them from …

    ever heard of a color organ? hehehehe im so bad, screw you warranty, i want my car to groove to the beat, LITTERALY!

    muhahahahahaha

  8. Having not read previous comments prior to posting this, why doesn’t he playback the same file simultaneously with a second delay in between them and just know what’s going to happen? Let’s say he’s just using some mp3 player code and reading the visual #, he could read it off of the first file.

  9. This is so forking awesome! I hate it when the wipers don’t synch with the music. And btw, how come they never thought of this on Pimp My Ride?

  10. I really liked that commercial, not just for itself but as an indicator that there are still advertising people out there who’ve used acid.

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