This is my first post-retirement hobby project: a remote controlled speaker selector switch box. I have small speakers in various rooms of the house, with all wires coming down to the stereo amplifier in the living room. Previously, I had a manual switch box that required one to actually flip physical switches. Now the same can be done from anywhere in the house, from any device that has a browser, such as a smartphone or tablet.
The box connects to my WiFi network and shows up as a simple web server. Four buttons control the 4 relays in the box to connect and disconnect speakers to/from the amp. The box places a limit on the number of speakers which can be on at any given time in order to prevent excessive load on the amp.
The box also has manual pushbuttons on the front and LEDs to indicate which speakers are on.
Yes, you can buy these things but this was a fun project and a great learning experience.
Internally, the unit uses an ESP8266 WiFi module as the brains. It scans the buttons and controls the relays and LEDs, and implements a simple HTTP server. The project uses Arduino libraries ported to the 8266.
The enclosure was handcrafted from sandlblasted aluminum (thanks Grant!) and solid oiled walnut.