Octoprint is an open-source system for remotely controlling and monitor your printer. Start/stop/pause prints, change printing temperatures and settings while printing, stream video, or captures images during printing. It does almost everything. With the wide range of plugins available you can even have more advanced features like being notified by WhatsApp or post on social media when a print completes. It uses a Raspberry Pi, a cheap, single-board Linux-computer for processing and interfacing.
Working with Linux and Raspberry Pi can for some seem daunting, but results are powerful so if this sounds like something for you, check out the links below for guides and more information.