Is it possible to do precise timing with fez? I know fez is not reatime because of gc etc. I want to build a pinwood derby timer and thought I might do it with fez. I suppose I could do the timing with an atiny then just read it weith fez but would rather just do it with fez. My design would look like one photo sensor to start the timer then another to stop it as the car rolls past. Any thoughts.
What do you mean when you say “precise”? Is 10ms accuracy enough? or you need 1ms…or even 1us or 1ns? “precise” can mean different things to different applications.
Anyway, this is a good question with a very long answer 
We added it to FAQ, please see questions “Is FEZ Real-time?” on FAQ page.