I'm not a YC founder/partner but as far as my knowledge goes, I don't think YC discriminates between hardware and software startups.
We had 6 hardware startups in the most recent batch in fact.
Sure!
Finally, robots!
I just want to ask whether a prototype and customers willing to use the product will be valuable for YC? The problem is we are an unproven team and because YC focuses more on the teams rather than ideas, should we wait for the YC S13 applications? Your take on that?
A prototype and customers willing to use the product are forms of traction that YC looks for. There is no harm in applying now and then applying again later if you get rejected, other than your time.
Is there a list somewhere of these metrics/things which look good/signs of success to have before applying?