SureKey is a smart key cover that lets you know you’ve locked the door or abandoned your keys

Did you lock the door when you left the house? Are you sure? It turns out, about 30 per cent of people aren’t. Short term memory has apparently become… er, we forget. Anyway, SureKey ($29) wants to help people know their house – and keys – are safe. This is done without potentially hackable smart locks. Instead, you glue your key into the SureKey, insert a CR2016 battery, and get cracking. When away from home, a green light informs you that your door is happily locked. And if you leave your keys dangling in the lock, more or less begging a dodgy crim to pilfer them, SureKey will make an annoyingly loud noise, which we’re reliably informed is key for “Come and rescue me, you blithering idiot”.