Hi, thanks for the help. I replaced by readStringUntil() but here is what I have
Serial Monitor[Arduino Side]:
12:27:26.753 -> Sending 0
12:27:28.852 -> Sending 1
12:27:30.863 -> Sending 0
12:27:32.862 -> Sending 1
12:27:34.869 -> Sending 0
12:27:36.881 -> Sending 1
12:27:38.889 -> Sending 0
12:27:40.897 -> Sending 1
Serial Monitor [D1 mini Side]
12:29:09.629 -> receive true
12:29:13.367 -> receive true
12:29:17.218 -> receive true
12:29:21.191 -> receive true
12:29:24.931 -> receive false
12:29:30.759 -> receive true
12:29:34.590 -> receive true
12:29:38.386 -> receive true
It's still not working as expected....It drives me crazy. It's been a day I'm looking everywhere. I read that it could be because of the speed
But I don't understand how to manage this problem.