CRAYFIS (Cosmic Rays Found in Smartphones) is a cool new project that plans to use the world-wide array of existing smartphones to detect low energy particles produced by high energy comic ray collisions in the atmosphere.
From the project website:
When cosmic rays strike the atmosphere, they produce a huge number of lower-energy particles in an an extensive air shower, which can stretch to many kilometers across. The very high-energy cosmic rays produce the largest showers, but unfortunately they are also the rarest. Only a detector with large surface area can observe these mysterious particles.
The current state of the art is large-scale arrays of custom-designed dedicated detectors. To see the highest-energy cosmic rays, we need a very large detector array of exisiting commodity hardware: the smartphones in everyone’s pockets.
Modern smartphones contain high-resolution cameras with digital sensors which are sensitive to the particles in a cosmic ray shower. They know where they are (GPS) and can upload their data (wi-fi). Most importantly, there are 1.5 billion active smartphones spread across the planet. Essentially, this detector has already been deployed; all that is missing is the app to collect the data.
Apparently the app uses your cell phone camera sensor’s chip while it’s idle, and works on both Android and iOS phones. However, the infrastructure to aggregate of all the data is still in beta testing. In the meantime, you can sign up to be notified when a full scale rollout of the free app is possible.
(image source: http://en.wikipedia.org/wiki/Cosmic_ray)