Testing Lithium Cells For Use With A Hybrid Car

June 29, 2012 by Mike Szczys 7 Comments

[Mikey] got a real deal on some A123 Pouch Cells. These are large Lithium cells that tolerate 100A discharge and 50A recharge currents, with 20 AH of life off of one charge. He’s been doing a bunch of testing to find out if the cells can go into an expandable battery pack and be made for use with hybrid cars.

We just looked in on a battery tester used for solar power car arrays. This is a similar situation except [Mikey] is focusing on the test data, rather than the apparatus. The link above is a collection of his notes from testing. Start reading at the bottom of the page up to get the chronology right. He starts to zero in on the most efficient charging methods. Immediately he’s hit with a big need for cooling as the cells take no time to pass 100 degree Fahrenheit. He continues testing with heat sink and fan, and even brings a thermal imaging camera to help with the design.

[Thanks Chris]

Electric Bike (earplugs Not Included)

June 29, 2012 by Mike Szczys 29 Comments

It’s obvious this bike has some extra parts. But look closely and you’ll see the chainring has no chain connecting to it. Pedaling will get you nowhere since [PJ Allen] rerouted the chain in order to drive this bicycle using an electric motor.

He’s got beefy motor which pulls 350 Watts at 24 Volts. For speed control he opted to use an Arduino, pumping out PWM signals to some MOSFETs. This results in an incredibly noisy setup, as you can hear in the bench test video after the break. But once this is installed on the bike it doesn’t quiet down at all. You can hear the thing a block away.

The original road test fried the first set of 7A MOSFETs when trying to start the motor from a standstill. It sounds like the 40A replacements he chose did the trick through. We didn’t see any information on the battery life, but if he runs out of juice on the other side of town we bet he’ll be wishing he had left the chain connected to the crankset.

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Bike Cross Country In Your Basement With Google Streetview

June 26, 2012 by Brian Benchoff 11 Comments

Biking cross-country is a worthwhile pursuit, but then you’ll have to deal with terrible drivers, rain, bugs, and heat. [Jeff Adkins] over at lowendmac has a neat solution to exploring the country via bicycle without ever leaving the safety and air conditioning of your basement.

For his build, [Jeff] used a magnetic reed switch attached to the frame of his stationary bike and the pedal crank. Whenever the pedal crank is turned, a reed switch closes on every revolution. This reed switch is connected to a new Arduino Leonardo programmed to transmit keyboard presses to a computer for every five revolutions of the pedal. From there, it’s a simple matter of loading up Google Streetview on a laptop and letting the Arduino automatically advance through Streetview images while pedaling.

The next part of [Jeff]’s project will be adding left and right buttons to his stationary bike to navigate Google Streetview images without taking his hands off the handlebars. You can check out a demo of [Jeff] cruising around after the break.

via reddit

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Bicycle Quadcopter Flies For Dozens Of Seconds

June 26, 2012 by Mike Szczys 32 Comments

If you decide to fly into town on this bicycle-powered quadcopter your arms and legs really will be tired. That’s because this athlete had to give it his all to power the rotors through the foot pedals and the hand cranks. You can see just one of the rotors on the right side of the background. Yeah, this thing is big!

You’re looking at the Gamera II, a craft developed by students at the University of Maryland. About a year ago they were showing off the first version of the aircraft. With the passing of the year comes the breaking of world records as a different rider manages to keep it up for 50 seconds in the video after the break. Although the structure is huge (over 100 feet across) the building materials and techniques let it weigh in at only 71 pounds.

It still looks like way to much physical work for us. We’re sticking to the pedal-powered hydrofoil as our dream transport.

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Stair Tricking Skateboard

June 22, 2012 by Mike Szczys 41 Comments

This skateboard concept lets you travel down stairs almost as smoothly as gliding down a hill. This seems to be the eighth iteration in [PoChih Lai’s] attempts to add functionality to a board which will make it the ultimate ride for an urban outing. Check out the video after the break to see just how well he did.

We’ve seen hand carts that use six wheels to make stairs a breeze using a triad of wheels as a single-wheel replacement. This was actually the main concept early on in the design. But the drawback to this method is that the design takes up a lot of room and [PoChih] also made the deck much bulkier to keep you from getting a foot caught in the mechanism. The final design does away with the end-over-end concept and adopts a rocking mechanism. The board hangs from a bar which serves as the pivot between the two wheels. This way the wheels can absorb the brunt of the motions, and the base of the deck can slide across the fronts of the steps if needs be.

We were talking about this here at the Hackaday office and the point was made that this is like YT’s skateboard from Neal Stephenson’s Snow Crash. Did you hear that it’s headed to a theater near you?

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Revolight Clone

June 20, 2012 by Mike Szczys 13 Comments

[Fabian.E] wanted to light up the rims on his bike, but didn’t want to shell out a bunch of clams to get it done. He came up with this system which uses magnets and reed switches to light up one arc or each bicycle wheel.

He calls it the lightrider and it’s based on the revolights concept. That design uses a microcontroller which is capable of animating patterns when the wheels aren’t spinning. [Fabian’s] version can’t do that, but the effect while moving is basically the same. The ring of LEDs around the rim is connected to a battery via a set of reed switches. When these switches move past a magnet on the fork it completes the circuit and switches on that segment of LEDs. The clip after the break gives a demonstration of the finished product, and includes a fast-motion video of the fabrication process.

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Milling A Motorcycle Engine

June 20, 2012 by Mike Szczys 30 Comments

Real motorcycle enthusiasts design and mill their own engines. Well, perhaps that’s an overstatement. Certainly it takes to more obsession than enthusiasm to go to these lengths. But this gentleman’s modifications started out simple enough, and managed to make it to the most extreme of hardware fabrications.

The used bike came with a modified camshaft that seemed like a botched job. As he got further into tuning up engine performance the prospect of just replacing the entire thing with his own design started to grow. Using a manually operated milling machine he cut his own molds for the new cylinder head out of wood and sent them off to be forged out of aluminum. They come back in rough shape but he just “filed the cast without mercy” and machined the tolerances to his specifications. Apparently the first test ride had him a bit nervous — he also milled his own brakes for the bike. But after a few times around the block he gained confidence with his work.

[Thanks Carlos]