I'm entertaining the idea of building a serial rs232 to MQTT or html dashboard bridge for a Roland M-400 V-Mixer using Node Red. Primarily I'm interested in remote aux sends level adjustments for the band at our church.
The serial commands are basic ASCII strings, STX followed by a three character command and parameters if applicable. There are three commands I'm interested in, channel names request (as set in the digital mixer), aux level request and aux level set. The mixer either replies with the requested data and listens for an optional ACK reply or replies with an ACK depending on the command. Any local changes on the mixer are not pushed out so Node Red will need to constantly request updates for MQTT but for a webpage, maybe it works to request data each time the page is loaded. The channel names don't change often so updating those every minute is often enough but the aux levels could change more often. I don't know yet how long it will take to sequentially request all the data (24 channel & 16 aux names and levels).
I'm leaning towards a html server setup such as the Node Red dashboard as each band member could use their own device without needing any extra software setup. A big question I have is regarding security, how to limit permissions/access to aux level changes. Ideally, each member needs their own login credentials to limit them to their respective aux channel and prevent anyone else from messing with it. The soundman logins could have full access to all the channels.
Does this sound doable? I'm not sure it's actually worth implementing but I heard that some digital mixers support this through an app so I started thinking about how I could add this to our setup.