A while ago someone built a flutter app that could interface with the API that I believe could scan barcodes.
Project - OpenEMR Android app - GSOC - OpenEMR Community (open-emr.org)
You can also get handheld usb scanner devices that should be able to read a UPC code and generate the text to write into a textbox in realtime as a “keystroke input”. There are apps that allow your smartphone to scan barcodes then copy to clipboard for you to paste in another application, in this case OpenEMR.
The question then becomes if such a solution can be HIPPA compliant.