Unfortunately, if you want to have a smart lock, you can't avoid a large piece of (usually) metal. At the start-up company Otto, they have now put an end to this. They designed and produced the smallest smart lock, which unfortunately is not exactly cheap. Well, let's see how she will protect us.
Otto lock it has no key slot and is completely dependent on mobile phone connections.
You can unlock it with a touch, but only if the mobile phone is nearby. In case of mobile phone malfunction, you can you turn the lock and thus unlock it via the PIN code. Otto even reminds you whether you closed the door or not. It has built-in Wi-Fi, so you'll be able to control it outside the house, but it shouldn't initially support 'home assistants' like Amazon Alexa, etc. According to company executive Sam Jadallah, this feature will be added a little later.
Compared to other smart locks, Otto is not 'smarter', but due to its size or small size definitely before them. Only the price leaves a slightly bitter aftertaste, because it is expensive 600 euros.
Gallery - Otto, probably the smallest and most expensive lock in the world