Let me preface this post by saying that I have read through the entire thread and have been unable to find a solution to the problem issued below. My problem is the same problem that Mulbin had a while back. I have uploaded the KSPIODemo to my Arduino Leonardo and my Arduino Mega 2560, made sure that they were on a specified serial port (in this case COM9), and then tested the LEDs to make sure they lit up on command (they did) When I ran KSP I saw in the Alt-F12 log they the plugin had started correctly. Upon going into the VAB, selecting a craft, and then clicking the launch button, my green LED would light up a few times while a the RX button flashed on my arduino. When the game was fully loaded the green light turned off and I received this message in the debug window. proof that the arduino was connected to the COM port. If someone could provide me with some guidance that would be fantastic. Thank you Edit: Tried with an UNO as well. Set the COM port in the config, tried raising the Handshake Delay. Restarted the game. No luck.
