We can extend the functionality of Google Sheets via Apps Script. This repository is a proof of concept to use Google Sheets as a MIDI sequencer. I built a custom sidebar UI for Google Sheets, and access WebMIDI API from there. Then, I connected my synthesizer via USB cable to the laptop. The script can read and send the MIDI data from Google Sheets cell and pass it to the synthesizer.
You can copy the sheet for this project from this link
