Where do I start to make a Theremin?

First off: I know that I don't have the prerequisite knowledge to actually make a Theremin if I have to ask this question, but bear with me.

I have basic knowledge of electronics but it's all very rusty. I love the Theremin as an instrument and have wanted to learn electronics (and become a hacker!) for a long time but never found any projects that caught my interest, so this seems like an ideal goal to work towards.

Let's say I want to make a really basic Theremin in 12 months or even 24 months. What knowledge do I need and how can I easily acquire it? I do have an engineering degree, but it's been more than a decade since I last refreshed my knowledge of circuits and antennas and it's mostly faded away.

I'm happy to provide more information or ask more detailed questions if needed.