Home automation: it's an offline system I wrote myself to tie together all the different systems where I would normally need separate (always online) controller

Home automation: it's an offline system I wrote myself to tie together all the different systems where I would normally need separate (always online) controller for each. That includes several soldered-to-GPIO-pins remote controls, and a HomeMatic and a ZWave radio module, although the latter is still controlled by the Z-Way software and I'm just using their API for those devices. It's a Raspberry Pi of the first generation, I'll probably replace the hardware soon. Audio: I'm also using one RPi2 with an attached hard disk as a music player for pen&paper roleplaying sessions, and I have 3 Pis distributed around the house acting as Wifi-enabled Airplay receivers attached to off-the-shelf powered speakers. Retro gaming: I built one RPi2 into an empty Amiga 500 case, it runs an Amiga emulator with many emulated game floppy disks onboard. Fun fact, the Amiga 500 keyboard sends its key strokes over a serial interface, so it's relatively easy to attach it to modern devices. 3D printing / IP cameras: I have drifted towards the Orange Pi hardware recently, mainly because they have a dirt-cheap headless module that costs about 10€. These are extremely useful for all kinds of automation tasks. For example, I'm using them with the Octoprint open source project to control 3D printers. Those headless Orange Pi Zeros are also fantastic as IP cameras, which has become necessary recently because consumer IP cameras that do not send all your data to China have become rare and expensive. Attendance and access control: I'm currently considering throwing out our shitty proprietary attendance and access management system at work, in favor of some simple custom-built Raspberry Pi or Orange Pi-powered panels. I have a prototype ready but haven't had time yet to make more. Lab control: I have an RPi3 attached via serial interface to a chemical analytics device at work, which required reverse engineering the proprietary protocol between the device and its shitty Win32 software. This allowed us to throw out a legacy Windows PC that needed to phone home all the time.