66% or better

Regenerative bike brakes

For their senior design project at Arizona State University, these guys built a regenerative braking system for their bike. As they brake, the system spools up to give them a push back up to speed.  They achieved 25% efficiency on one run, which isn’t too shabby.

The site has all kinds of information. You can check out their different plans and ideas from before they decided on this specific layout as well as all their data from the test runs. Be sure to look at the piece by piece breakdown of what changes were made from the initial design.

[thanks Mario Gomes]

Hack a Day Fail Whale Contest

We’re back! There may be a bit of oddness for the next few days. Our Fail Whale contest is still running and we’ve received over 100 entries so far. Here’s how you can participate:

While we’re adding more hamsters to our server power plant we thought we’d hold a little art contest. Whenever Twitter goes down, they post the iconic Fail Whale. The Fail Whale has become so popular that it has spawned a dedicated blog and many many art projects: embroidery, tattoos, and laser cut models.

We want to see what you think Hack a Day failure looks like. Create an illustration, photo, sculpture, anything that you think embodies Hack a Day failing. Send your entries to hackaday.fail@gmail.com and add them to the Hack a Day photo pool. The prize is $100 for you to spend in the No Starch Press store. Entries are due 00:00PDT Saturday September 6th 2008.

[image: Bjonnh]