I am another one to try the $50 robot. Long time programmer first time this close to hardware. Anyhow, I have been following the simpler "schematic" provided in the post "$50 Robot with AVR ISP mkII 6 pin" with a visual representation of the solder points. It turns out i am not bad at soldering. I only blew out one terminal by overheating it with my iron set too high! The next one will look much better.
Anyhow, my question is what is the purpose of the capacitor located between L18 and L20? It appears(to me) that it only offers anything to the 6 pin programmer pin 2 since it is after the two connections on the controller. This is based on "BASIC ELECTRONICS COMPONENTS TUTORIAL FOR ROBOTS" description from this site. However, maybe it is because of the mention that electrons flow from ground to source? Based on that description the capacitor between D11 and E11 makes sense to me.
Thank you for the info!