Internet of Things (IoT) can include both output devices, like smart plugs, and devices for monitoring your home. The latter type can include smart doorbells and WiFi-connected security cameras. You can also use sensors to monitor the conditions within your home and gather environmental data like temperature and humidity. Josef Adamčík built this home room monitor using an ESP8266 board and three custom PCBs arranged to form a three-dimensional structure.
This device can monitor the temperature and humidity through an SHT30 sensor, barometric pressure and temperature through a BMP280 sensor, and light levels through a BH1750 light intensity sensor—though a simple photoresistor was originally used. The environmental data is displayed on a small LCD screen that is connected via I2C, and also sent to a separate Raspberry Pi over MQTT messages. All of that is handled by a single Wemos D1 mini. A LiPo battery provides power, and a TP4056 charging module tops that off when needed.
That’s all pretty standard stuff, but this project stands out because of the unique PCB design. Adamčík actually had three unique boards fabricated, and they are soldered together at right angles to create a 3D PCB. Huge solder pads are used for those structural connections. That’s not the strongest mechanical connection, but it should work for a device like this that isn’t subjected to any kind of abuse. Adamčík designed the boards by drawing the outlines in InkScape, and then imported those into KiCAD as DXF files. The finished IoT room monitor looks nice, and can reliably monitor environmental conditions.