When I try to install the Tiny boards in Arduino Board Manager, I get the following error:

Code Select Expand

no protocol: http://files.tinycircuits.com/ArduinoBoards/package_tinycircuits_index.json

Any ideas?

Have you added TinyCircuits to your "Additional Boards Manager URLs" under Preferences? You need to add this link before you can install the boards:

http://files.tinycircuits.com/ArduinoBoards/package_tinycircuits_index.json

If you're still getting the error, check your firewall settings to make sure Arduino IDE can communicate with the Internet.