Hi, thanks for your answer, I saw it late because I think I would receive a mail when someone answered.
In this time I find a solution using only touch down and touch up event, but I modified the code on arduino to work in this way.
anyhow I would like to understand your solution and try it, but I don't know how set a clock to do what you said cause it's my first time on app inventor.
could you send me please a screen to how set the blocks with a clock?