BitTorrent Sync is a free utility that uses the bittorrent protocol to keep folders in sync across devices. It can be used with OS X, Windows, Android and Linux. It is not however open source, which might be a deal breaker for some. But if this isn’t too big a pill for you to swallow, with a little bit of work you can use btsync as a free syncing solution.
While Dropbox requires you to keep a copy of your data on their servers, btsync never requires your data to inhabit a device you do not own. This is nice for security, but it means to sync between two devices they both need to be online at the same time. That is where the Raspberry Pi comes in. You can use the Pi as a node in your sync network, so a change to a file on any device will sync with the Pi and then other devices will get the change when they come online.
First we will set up the Pi as the central server and then we will connect our devices to it. (It is important to note however that the Pi is not a special “server” node, it is just a regular node like any other device.)
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.