Build a smart doorbell with a Raspberry Pi, some sensors, a buzzer, Node-RED, and Apple Home Kit. Sometimes the most effective home automation projects are the ones that solve very simple problems. Here’s my simple home automation IoT solution. I have trouble hearing my door bell when I’m working upstairs wearing headphones, so I’m going to create a smart doorbell system: I’m going to add a motion sensor to the front door of my house that will activate whenever someone is at the front door; I’ll also add a temperature and humidity sensor that I can use to monitor the conditions outside my front door at any time, so I won’t forget my coat or umbrella when I leave the house if I need them; I’ll use the PIR sensor to trigger a relay to turn on a strip of LED lights to make it easier to see to unlock the door when I get home after dark; I’ll expose all of these sensors as Apple Home Kit devices. Home Kit is Apple’s home automation framework that allows you to read from sensors and control smart devices that are installed in your home by using the Home app from an iPhone or iPad running iOS 10, so I’ll be able to see the sensor readings from my phone.”