Here are all the notes and files from the Plano Train Show Clinic. You need to have an internal sensor ( IMCOMPORT ) with the port in the value like COM10 or /dev/ttyUSB0 , whatever Device Manager (or /dev/ttyUSBx) shows for the connected Arduino. If you have Panels -> Script Output open, you will see the message: !!! Please add IMCOMPORT with the port in the value!!! The basic idea here is to use the Comment in the Signal Head field to define the position of the Pixel in the string commented to the Arduino, as well as the RGB colors to show for Clear, Approach and Stop (00:00 FF 00: BBAA 00: FF 0000). With all the Heads in the Table, run the python script and now you can update the colors in the Comment "live", keeping in mind that a message is only sent when a Head changes color. We then put the Heads in Masts and use the Signal Mast Logic to do the magic. I like the original Panel Editor more and it works fine as long as you keep using Mast pairs, which require