I am new to Arduino and looking forward to my first project. I am replacing the relay system in a Pinewood Derby Christmas Tree Start gate that was run off a Parallel Port in the past. The old relays caught on fire during its final race of use. The software used for running the Pinewood Derby race no longer uses parallel ports. It now relies on the use of a RS232 serial port to trigger either a start gate solenoid or a Christmas Tree that fires a solenoid at end of its routine. The only options are using a Serial COM port in windows using either PIN 4 or 7 with PIN 5 as the ground. The output voltage is 6.11v when on and -5.65V when off.
I am trying to determine what additional work and electronics I will need to connect to an Arduino. I was looking to use an Arduino UNO as my starting point connecting to an 8 Channel DC 5V Relay Module to trigger the AC light on the Tree and close the circuit to release the solenoid that relases the Pinewood cars and starts the timer.