This app was mentioned in 3 comments, with an average of 1.00 upvote
not in a situation where I can watch the full video at the moment so I'll make some assumptions, let me know if I'm wrong on anything.
assuming the host pc is driving it via usb serial.
I'd probably look at sending OSC commands to the host computer to forward them to the code you already have.
TouchOSC and Lemur should both fit the bill as they have customizable interfaces and an X/Y pad you could use.
https://hexler.net/software/touchosc-android https://play.google.com/store/apps/details?id=net.liine.lemurapp
If you want to step it up a bit without much coding, you could look at some of the automation tools. Tasker, automate etc and use accelerometer data etc to drive it too. I'd probably do my best to be sending these commands over UDP.
As it's a laser you don't really want to get hung on waiting for TCP packets in the case that it has moved into a dangerous position, ie near someones eyes.
Have fun!
I use a USB MIDI adapter (the most god-awful cheapo one I could find too) on my Android and it works just fine for me. The audio-latency issues that Android has don't affect MIDI over USB.
I use a standard USB-micro to female USB-A OTG adapter (like $5 from Amazon) with the USB to MIDI adapter, and have had no problems. I primarily use it as a MIDI monitor to troubleshoot my setup, but I've also used it for setting up controllers for various things.
Both Lemur and Touch OSC are available for Android devices, and they will let setup all kinds of controls. I haven't used the sequencer in Lemur personally, but I know it has one.
https://apps.apple.com/us/app/lemur/id481290621
https://play.google.com/store/apps/details?id=net.liine.lemurapp&hl=en_US&gl=US
It's an iPhone/Android app, there isn't a "them" to sell.
This is their website, https://liine.net/en/products/lemur/
but it doesn't seem to be maintained as there's are SSL issues... this is the video on the site: https://youtu.be/BPFKkCQduCc