Not my hack, but a team effort. Many years ago, I worked for a premium car manufacturer. We wanted to present a new product idea to convince visitors from HQ th

Not my hack, but a team effort. Many years ago, I worked for a premium car manufacturer. We wanted to present a new product idea to convince visitors from HQ that we had a project worth funding: The core idea was that the car could be opened not only with the normal car key but also by other means, for example from a smartwatch. Usually we would simply have modified/rewired a car so that a bluetooth connection to open it would work (for the demo only, of course). However, the keyless entry was designed to be so secure that it would have taken us far too long, even with our insider knowledge. My team leader had the brilliant idea of simply printing a 3d housing in which the original car key and an arduino-controlled servo could be installed, so that the arduino could press the key. We placed this device close to the car and remotely controlled the arduino. The demo worked perfectly and everyone was happy (afaik the project was not funded though).