Alimentation of 2 mega 2560 and 2 multiplexer 16 ch

Hi everyone, just a little question, I have the project of create a midi controller for ableton with 2 mega 2560 in serial and 2 multiplexer analog 16 channel, to finally have 64 analog input and 108 digital input, will the power supply of one of the cards via USB be sufficient? and if not what should I do?

Thank for your answer and sorry for mistake I'm french !

2 mega 2560 in serial

What does this mean?

You do not need two processors for this project, just get your self some port expanders for the digital inputs, like the MCP 23S17.

For the analogue inputs use analogue multiplexers. You are just making work for your self. Will the USB be sufficient? It is impossible to say without a full schematic of the circuit. If it is not then you will have to use an external wall wart power supply, no big deal.

Thank for your answer ! Ok thank you for your help, I would try to be more precise when I would have more advanced in my project and give you a schema.