New fitness device biometric
Ideal for all the fitness types also, combine the thing with a blood glucose reader and a DNA sampler and you have it taking a blood sample to access it. Incorrect blood sample and you don't get in. The blood glucose sample is just used as the marketing front :P
Other advantage with it having to take a blood sample to access is on a phone at least it'll stop people fiddling with the things all day long. Or am I just being a grumpy old git?!