RattleGen, to Power Your Bike Lights.





Introduction: RattleGen, to Power Your Bike Lights.

The RattleGen is a kinetic electric generator to power your bike lights, for example.

In my search for a dynamo- and batteryless bike light, I found only 2 brands working on the same principle. I had to come up with an other idea using the movement of some bike parts.
Playing with coils and magnets I discovered a new phenomenon. I toke a mechanical relay and put a strong magnet against the iron around the coil. By pressing the contact lever I changed the magnetic flux inside the core of the relay and induced an electric pulse inside the coil. First I used a small 12 volt relay. Later I used a bigger relay and placed the strong ceramic magnet directly agains the coil. The pulse that came out by tipping the contact lever was about 30 volt. A LED was flashing with a serious amount of light. The RattleGen was born. A nice feature is that the linear movement is only 1 mm. I never saw this principle used for vibrational energy harvesting, but I don't know all. The power output of the RattleGen is quit high.
So, how to make this RattleGen useful for my bike lights? The best is as light and generator are placed in the same lamp housing. In this project I show you the prototype and the way I solved some construction problems. The linear movement I get from the spokes of the wheel, near the rim. A lever hits the spoke and that movement presses the contact lever of the relay. I didn't try the profile of the tire as vibrational source. The video instructable show's you how easy the RattleGen can be made. To get the same relay as I used can be hard. The few other accessories you can find in most electronic parts shops.



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    In Montreal we have rental bikes called Bixis (https://montreal.bixi.com/main.php?l=en). They are equipped with lights that flicker when you roll and the bikes makes a peculiar rattle sound. Something tells me some kind of rattle generator is under the hood of this. Very interesting post by the way!

    it could generate power off a windmill or a small waterwheel...would be fun to have a small windmill that lit up different lights depending on windspeed.

    i liked everything besides the noise it creates

    Using the spokes is maybe not the best example for using the RattleGen. I think there are enough vibrational places on the bike to tap energy. For example the profile of the tyre. Rolling a small wheel over the tyre will do. 1 mm movement is enough to induce power. All has to be optimized for that. My aim is to combine generator and light in the same lamphousing to tap contactless energy. So, without rattle...

    You could use an eccentric roller, i.e. with the hub offset from the center, thus it would wobble up and down.

    Michael, are you fortune telling? This is exactly the thing I am working on.

    I would help if you moved your text line up a bit, the youtube pop-up control blocks it.

    I found this a bit disapointing. I thought frame vibrations would cause the rattle. This seems like it would over time damage the spokes or lead to a less true wheel. How is this an improvement over the equivelent dynamo on sidewall approach?

    depending on how well the wheel is maintained. it shouldnt cuase any problems wat so ever.

    I love this design, I'm going to have to tinker a little with this concept. Just wondering, if you moved the unit closer to the hub of the wheel would it reduce the rattling? the spokes then wouldn't be hitting the wheel as fast (might make it quieter), but your switch device wouldn't be actuated as quickly. Would changing the time that it takes to flip the switch reduce the flux? Maybe not, since it's a switch rather than a loop continuously changing loop...