Short update: Numpad block arrived and assembled!
Door lock. Alarm system activation / deactivation. Protocol execution. These are some of the ideas I had in mind while designing this board.
The list of parts is pretty simple: The ESP12 and the numpad (obviously), a MUX to increase the amount of pins on the ESP and an LDO for the power supply. After quickly assembling it I only had to write some code for reading out the keypad via the MUX (which takes a bit longer than just using a library) and add the ESP_basic to upload the entered number into my smarthome system. Once there, I can decide what I want to do with that information: Use it to enable / disable an alarm? Use the entered code to activate a specific protocol? #1337 could result in the lights going green, an electro playlist starting to play and the coffee machine going on, for example.
Unfortunately though my smarthome is still lacking some action, just anything interesting to do. In the future I’ll add some Philips Hue lights, connect my coffee machine to the system and start setting up my surveillance (I already built reed switch blocks so I can read out door / window states). But until then, the keypad is nothing but a gimmick.