Port of Moppy Arduino code to AVR C for select AVR microcontrollers. Will be compatable with the Moppy Java program in the Moppy repository.
Link to the Hackaday Projects page for this thing.
Currently, the code compiles to smaller than 2Kb, so with some editing this could be used on an ATtiny2313, which has hardware UART. I do not have an ATtiny2313 to test on, so haven't tried.