True randomness can be hard to come by in the digital world. [Andy Green] is making it easier to get true entropy by using this random USB dongle. The Whirlygig uses a CPDL to gather data from a set of of oscillators. The oscillators have a constantly fluctuating frequency due to temperature changes; if they run faster they generate more heat which in turn slows them down. This, along with the variable latency associated with polling a USB device, gives great depth of randomness. The device is detected and mounted under ‘/dev/hw_random’ and can then be fed into ‘/dev/random’ using the rng-tools package. [Andy’s] done a lot of testing, both on the hardware, and on the quality of randomness. We didn’t see an option to order this but he’s got hardware and firmware repositories so that you can throw one together yourself.