A Pedal Powered Cinema

When the apocalypse hits and your power goes out, how are you going to keep yourself entertained? If you are lucky enough to be friends with [stopsendingmejunk], you can just hop on his pedal powered cinema and watch whatever movies you have stored on digital media.

This unit is built around an ordinary bicycle. A friction drive is used to generate the electricity via pedal power. In order to accomplish this, a custom steel stand was fabricated together in order to lift the rear wheel off the ground. A 24V 200W motor is used as the generator. [stopsendingmejunk] manufactured a custom spindle for the motor shaft. The spindle is made from a skateboard wheel. The motor is mounted in such a way that it can be lowered to rub the skateboard wheel against the bicycle wheel. This way when the rear bicycle wheel spins, it also rotates the motor. The motor can be lifted out of the way when cruising around if desired.

The power generated from the motor first runs through a regulator. This takes the variable voltage from the generator and smooths it out to a nice even power signal. This regulated power then charges two Goal Zero Sherpa 100 lithium batteries. The batteries allow for a buffer to allow the movie to continue playing while changing riders. The batteries then power the Optomo 750 projector as well as a set of speakers.

10 thoughts on “A Pedal Powered Cinema

  1. The specified projector uses a 230W P-VIP (Osram trademark for mercury/halide HID) lamp…it’s either being run at some crazy “eco mode” (meaning the image is dim as a candle) or the 60W power draw is bullshit…what is it measured with?
    I ask because the switchmode ballast for the projector lamp and whatever converts the 2x12V to what the projector wants tends to confuse non-rms meters…

    – the friction drive looses precious power, why not use a hub motor (with appropriate electronics), which combined with the batteries could help with hauling the setup?
    – at a combined price of $700 and a combined capacity of >200Wh, the power packs are pretty expensive…wouldn’t a separate charge controller, battery pack (BMS included) and voltage inverter cost less?
    A 12V 20AH 7pound Lithium pack (lead-acid drop-in replacement) can be had for ~$300, MUCH less if you make it yourself (requires special tools though)…

    1. Where do you get the idea that the project uses a HID lamp?? Do you even check the project page? The Optoma ML750 uses a maximum of 62 watts with LEDs…

  2. This reminds me of an exhibit that used to be in a museum somewhere in or near Saint Louis. You pedaled a bicycle and it ran a camera and you could see yourself on a TV.

  3. That’s no ordinary bicycle! It’s a shame that it’s not electric drive. It looks like it was made for electric.
    If the flow was reversed, 200 watts ain’t much on an e-bike. Friction drive sucks. At least in a gen mode it’s just wasting your power not that from the battery.
    An e-bike with regenerative braking could be ridden on a stand. Set the brake to a usable level and connect to the battery.
    Weather it’s for Holeywood’s version of disaster or the real thing it’s (rapid deployment for theater operations or a ham radio emergency station in a blackout) it’s sure to be a hit.

  4. “When the apocalypse hits and your power goes out, how are you going to keep yourself entertained?” I was planing on rape and pillage but I suppose I could go for a movie. (I will be eating popcorn out of the skulls of my enemies though, hey this is the post apocalypse.)

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