PHP Runtime Rewritten, By Facebook?

February 3, 2010 by Jakob Griffith 42 Comments

Yes, its true. Facebook has completely rewritten the PHP runtime to make it faster and more efficient, and its completely open source. Named HipHop, its described as a source code transformer, changing PHP into optimized C++ which is then compiled using g++. Thus keeping the best aspects of PHP while taking advantage of the performance of C++. Using HipHop, the Facebook web server CPU usage has been decreased by about fifty percent! And who would have thought that this and many other cool advances in programming, started at a Hackathon.

Bike Trainer Computer: Speed, Cadence, Heartrate, Trainer Temp

January 12, 2010 by Mike Szczys 13 Comments

[Kurt] was using a bike trainer to get in shape for warmer and dryer biking months. Unfortunately it’s pretty hard to train if you don’t have reliable data concerning how hard you’re working. There’s commercial solutions for trainer computers but he’d read some rough reviews about them and decided to build his own trainer computer. He’s done a great job of integrating a lot of different data collection sources. He picked up two replacement bike computer sensors to use on the back wheel for speed (the front wheel is stationary with this type of trainer) and on the crank for cadence. He also wears a heart rate monitor and sourced a SparkFun heart rate module to gather that data. Finally, an LM235 analog temperature sensor was combined with a spring clamp to detect the temperature of the trainer’s resistance module.

Data from the sensors is collected with a PIC16F73 microprocessor and fed to a computer over a serial connection. He’s got a screenshot of the realtime graphs that he’s using for feedback while on the bike. This is a useful and practical setup but when he get’s tired of exercising he’s just a few lines of code from converting this into a gaming controller.

[Thanks Justin]

Capturing Bullet Speed

December 13, 2009 by Mike Szczys 20 Comments

Sometimes it’s amazing how slow our sense of time is. We find [Maurice’s] bullet capture system a great example of this. A pair of IR sensors spaced two inches apart can capture and calculate the speed of a projectile. Couple this with a user-input distance from the sensor to the target and a microcontroller can extrapolate the exact moment to trigger a camera to catch a bullet in mid-air.

As with his other projects, all the details on how to build and use this system are available for your perusal.

Beauty In Destruction

October 9, 2009 by Phil Burgess 49 Comments

[youtube=http://www.youtube.com/watch?v=QfDoQwIAaXg]

This is not a hack. In fact it’s a promotional montage for a collection of scientific equipment that few of us could likely afford. But like yesterday’s giant marionettes over Berlin, sometimes even a costly and delicately-orchestrated achievement transcends its own not-a-hack-ness, fulfilling our brains’ lust for wonderment all the same.

Kurzzeit of Germany produces ballistics measurement equipment. The video depicts various combinations of projectiles and targets at up to one million frames per second, revealing unexpected beauty in hitherto unseen phenomena, and is the best damn ten minutes you will waste on the internet all day!