Back at CES, Sony unveiled a curious wearable: the Core, a miniscule activity tracker made to slot into accessories, like its SmartBand. At the time, details surrounding this waterproof sensor were scarce, but here at Mobile World Congress, weve gotten more insight into how the tiny tracker fits within the One Sony world. And as you can see above, Sonys exploring ways to pair it with a camera you wear around your neck, so its always ready to document your day.