It should be possible to do this with a simple userlib. Here's a thread on the topic - 20 years old but it might be useful!
https://archive.blitzcoder.org/forums/b3d-programming/53540.html
I tried a few different B3D serial comms userlibs over the years always hoping to get one working, but to no avail. I don't know why they didn't work, but they were always blocked in some way! Other languages I use such as VB6, LibertyBasic, Just Basic, Free Basic, Python, Processing usually get me started, Their serial comms libraries don't get blocked, but I always want to use Blitz3D for the great 3D stuff! Creating intermediate serial comms 'drivers', that suck in the serial data from Adruinos, and output the data to files in RAM disks, to be read back into Blitz3D is a real pain and very slow! How I wish serial comms was built into B3D to help with this. I really feel that would help open up your userbase to others wanting that hardware capability too!