so i got a request from an artist friend..
he wanted to use a couple of hometrainers to play audio. (more specifically the Bird Dance or the Chicken dance or whatever it's called in english. yeah, i know. long story.)

the idea was: the faster you pedal, the faster the music plays. it'd be nice to be able to 'scratch' with it, and pedaling backwards would have to play the music backwards.
one machine would do the drums, the other would do the melodic info, so you can try to play together.

here's what the (intermediate) results sounded like:
https://youtube.com/shorts/U-yurgWrw4M

i may have ended up tweaking the response a little, but that's the general idea.

here's the actual installation in a gallery in Cologne:
https://youtube.com/shorts/0oFOh8MGemE

you can go and ride the bikes until october 1st, so you'd have to be quick. 🙂

    some techy nerdout info:

    each bike has a Bela Mini inside, running a custom Pd patch.

    i mounted 6 magnets on the bike's axis, with a magnetic sensor to determine speed.
    funny thing is: there already was a magnet mounted in there for the Speedometer, but having only one magnet per revolution was way too low of a resolution, since it takes two full revolutions to even calculate speed. good enough for exercise maybe, but not for scratching.

    mapping pedal speed to playback speed is rather trivial.
    difficulties were determining when the pedaling has stopped and what slow-down-to-stop curve felt natural, and determining pedaling direction.
    the first was a matter of trial and error - did a lot of pedaling during the heatwave. hah.
    the second was another challenge alltogether. in the end, i mounted two sensors right next to one another along the magnet's travel- that allowed me to check which one fires first, and therefore in which direction you're pedaling.
    seems simple enough now..

    i actually think if you were to write some custom music files for them, you could do great shows with them 🙂
    now.. well, it's a concept, haha.
    it does tie in with his other work, though. in his official will, there's a clause that when he dies, there has to be a Beer Bike (you know those horrible party bikes with a beer bar inside them?) riding around Antwerp playing only the chicken dance in a loop.
    he'll be screwing over his mates from beyond the grave, basically. artists. 🙂

    alt text

    here you can see the bike's insides..
    the red blocks are reed relays that i used as sensors. as you can see, the magnets (small grey circles on the axis disk) pass by both of them one after the other.
    the white tubish thing next to them is the sensor for the speedometer.

    on the bottom is the bela mini + custom shield. power is provided over usb (phone charger).

    i enjoyed this build a lot, learned a couple of new things. fun!

    Remork . (more specifically the Bird Dance or the Chicken dance or whatever it's called in english. yeah, i know. long story.)

    il ballo del qua qua!

      now there's a version i'd never heard before 🙂