Ask HN: How would I get started building an at home EEG monitoring product?

I've been reading a book called "The Promise Of Sleep" to learn more about my troubles I've had sleeping over the years and it's inspired me to start hacking and gathering my own data about my sleep patterns.

I'd like to take a shot at building an at home EEG machine to gather data on my brain activity at the time I fall asleep and throughout the night. I've been searching around for existing products that let me have access to the data and I can't find anything so I'm looking into building something. I'm not even sure where to begin though. I'd need to start with some EEG electrodes but not sure how I can capture the data from the electrodes. Does anyone have any experience or ideas on how I can get started?