Dear Pixy team
When I look at the code you proposed to interface ARduino and Pixy with a UART, it looks like the Arduino has to wait for a message from the PIXY. If I am correct it can be improved by using the interruption (connect the Tx to an INT on the Arduino).
I would like to try it but in this case, I need to know how the data are encoded in Hex format. Is it possible to know how you encoded the blocks (header of the message, data …)?
Thank you very much for the clarification and congratulation it is a nice device 
During the kickstarter campaign you mentioned that you were working on aface recognition program, what is the status?
Fabrice