Building a bike for 100 miles per hour



As a kid, [Tom] followed all the automotive land speed record attempts on the Bonneville Salt Flats. The cars used in these attempts were all built by guys in their garages, and as a bicycle frame builder, [Tom] is keenly aware of the land speed record for bikes. One thought leads to another, and [Tom] decided he would see how fast one of his frames could go.

Aside from a gigantic gear for his custom bike, [Tom] also needed a little help from a friend. The current land speed record on a bicycle was done by drafting behind a drag racer. [Tom] doesn’t have a drag racer, or a wide expanse of flat open ground in his native England, so he did the next best thing: drafting behind a Ford Zephyr on an abandoned WWII airstrip.

On the runway, [Tom] was able to get his bike up to 80 miles an hour. Wanting to see how fast he could go in ideal conditions, the bike was taken to the garage, put on a pair of rollers, and measured as it was brought up to speed. With a lot of effort, [Tom] was able to get up to 102 miles per hour, incredibly fast for something powered by human muscle.

Shifting gears on your pig roasting spit


[Tim] and [Jon] have a hankering for some pork product of their own making. Your average residential kitchen is ill-equipped to handle an entire pig, so they got down to business building this pig spit out of old bicycle parts.

The main components in the project are two stands built out of square tube which go on either side of the cooking fire (coal bed?). They include bearings to support a horizontal bar on which a pig carcass is somehow mounted. The whole point of a spit is to turn it while cooking, and that’s where the gear system comes in. The front crank from a bicycle was welded onto the spit, with one pedal still in place. This way if the motorized system breaks down they can still turn the thing by hand.

The crank connects to the cogs with one chain, while the other chain connects the cogs to a windshield wiper motor. When connected to the specified 12V it turns around 6 rpm; close but a bit too fast. After some trial and error they found a 5V supply turns it at the optimal 2 rpm.

We wonder if you can put a whole pig in a meat smoker?

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Rattle generator is a new type of dynamo for a bicycle


This project is in one of our favorite categories; the kind where asking “why?” is the wrong question. [Berto A.] built the device after observing some power generation by placing a large magnet next to a mechanical relay coil and quickly clicking the relay’s lever. From this humble beginning he built up the RattleGen, a bicycle spoke driven generator.

To get the most power possible he searched around for a massive relay and found one which was originally meant for telephone exchanges. He cut the case open and strapped a big bar magnet to the side of the coil. Next he fabricated an arm which will press against the relay’s lever. To that he added a small wheel which is pressed each time a spoke from the bicycle passes by it. This repeated clicking of the relay lever generates a current (and a rattling sound) that is harvested by the joule thief circuit built on some protoboard. An LED is illuminated, with excess current stored in the capacitor bank. Don’t miss the build and demonstration video after the break.

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Dynamic bicycle headlight uses the open road as a display


This thing is so cool it almost looks fake. But [Matt Richardson] isn’t a hoaxster. He actually built what might be called a heads-down display for your bicycle. He refers to it as a headlight because it borrows a similar function. It mounts on the handlebars and shoots light off the front of the bike. But it’s more than just a battery and a bulb, this uses a pico-projector to give that light some meaning. In the video after the break he shows it off on the streets of NYC.

So far he’s only displaying information that has to do with the speed of travel, but the proof is there just waiting for a brilliant new use. Feeding the projector is a Raspberry Pi board. For this prototype [Matt] mounted it, along with the portable cellphone charger which plays the role of the power source, on a hunk of hardboard strapped inside the bike frame.

If you’re thinking of doing this one yourself beware of the BOM price tag. That projector he’s using runs upwards of $400. We wonder if you could hack together a rudimentary replacement with an old cellphone screen and this diy film projector?

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Brake Light Backpack overpowered with LED pixels


Here’s another Flora Arduino based project from [Becky Stern]. It’s a backpack with brake lights and turn signals for use when motorcycling, but it should work just as well for bicyclists. From this view the project looks pretty normal, but things get downright crazy when she decided to use the WS2801 pixels for the LEDs. Sure they take all the work out of driving an array of LEDs, and they offer full color and dimming levels. But when you see the bulk of cabling and PCBs this adds to the project (shown in the video after the break) we think you’ll agree that this was an interesting choice.

That issue aside the project is a lot of fun. The system doesn’t patch into the motorcycle’s electronics. Instead, it uses an accelerometer to detect when the brakes are applied and light the LEDs according. The turn signals are switched with an RF remote control that can be mounted on the handlebars.

Anyone looking to hack outerwear with electronics can learn form the fabrication techniques used here. [Becky] details how to make holes in the bag and sew parts to them, as well as using Sugru to waterproof vulnerable components.

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Brilliant auto-off feature for a bike light


If you’re going to use your bicycle as transportation at night you really must have a head and tail light in hopes that the crazy drivers don’t hit you. For good reason, these lights don’t turn themselves off. But [Miceuz] kept forgetting to shut it down upon arrival and always ended up with dead batteries. His quest for an auto-off feature that actually worked ended in a brilliant and simple add-on circuit.

He first thought about using an accelerometer, but couldn’t find one that fit the bill without also adding a microcontroller. He came up with an even simpler circuit, which can be seen at the base of the black plastic housing. It’s a bit of copper clad board with a small spring attached. The spring completes an RC timer circuit which drives a MOSFET. When that circuit is charged, the MOSFET connects power to the bike light. When the cap runs out the MOSFET threshold cuts power and everything turns off. Since the spring jiggles while he rides it provides the momentary connection necessary to charge the capacitor. Stay stationary for about 30 seconds and the auto-off kicks in.

Barometer tells you to take your bike or the train


Before beginning his day, [Richard] needs to decide whether he should ride his bike to work or take the London tube. All the information to make that decision is available on the Internet – the current weather report, and the status of the subway lines and stations he’d be taking. The problem, though, is all these pieces of information are spread out in multiple places. [Richard]‘s solution to this was to make a bicycle barometer that pulls data from these places and makes the decision to ride a bike or the tube for him.

[Richard]‘s barometer is built around a nanode and an old clock he found at a flea market. The nanode queries the UK’s weather bureau and the London underground’s line and station status. All the variables under consideration are weighted; if it’s snowing, the output is much more likely to decide on the tube than if there was a slight drizzle.

It’s a really cool build that certainly makes a great use of the publicly accessible APIs made available by the London underground. You can check out a video of the barometer after the break.

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