Hi,
I am considering the same thing and already have to do some digital work. I was familiarized with programming languages that serve industrial design prototyping such as Python+VRML, Max/MSP and Processing+Arduino but there is just a lot of demand for mostly digitally mediated experiences nowadays. So, start developing an app! App design is the first area I would look into since with basic principles of usability/interaction design and user testing methods you can become good at it quickly, especially with development platforms being more and more accessible. Apps also have great opportunities to be combined with physical devices so you can bridge the two fields.