Steve Caplin looks into the latest tech, with Sainsbury's opening a checkout-free store – again, this time in competition with Tesco. South Korea is introducing dancing, singing and farting robots in 300 nursery schools, there's a singing cactus that's ruder than expected, an air taxi that will make you feel you're Superman, a camera the size of a grain of salt, the oldest iron and fridge that are still working and a way of using two lenses at once on an iphone.
