I live in an old apartment with an old intercom, which became considerably less charming once I had my sleeping 6-month-old on my chest and someone waiting downstairs. I stuck this tiny button-pushing robot onto the buzzer, calibrated how hard and how long it should press, and was done in five minutes. Now I can let people in from my phone without waking the baby. It has also become a de facto spare key for my husband, whose relationship with keys is mostly theoretical.
You can attach it to almost any physical button — a light switch, coffee maker or whatever other part of your home has declined modernity. Add a compatible Bluetooth gateway and Alexa can do the pressing for you. Most smart-home upgrades require replacing the object. This one simply assigns a tiny robot to press it.