I've been working on a small project - after building an SdriveMax.  I've wanted to make it smaller and internalize it. Have it working now.   Pros: A little cheaper - no screen, no SIO plug Internal - less stuff to lug around Smaller - uses a smaller Arduino with the same chip (Arduino Nano) Powered off constant 5v rail of the main power switch, power controlled using the channel selector switch Built in the 7407 circuit so should play nice on the SIO bus