for the last couple of months I have been working a bit on a flow-based programming runtime for microcontrollers. It is still very early in development, but the recently released version now lets you program your Arduino in a visual way, similar to Pure Data and similar, but able to run 100% standalone.
The project is free and open source software, released under the MIT license. The firmware is provided as an Arduino library you can flash to your device. For more information see: http://www.jonnor.com/2013/11/microflo-0-2-0-visual-arduino-programming/ http://github.com/jonnor/microflo http://microflo.org/