Running the same passive project as 2017 - a day trading robot focused on Canadian (TSX) market conditions. It's been wildly successful closing positions on a nightly basis and exploiting market patterns that work at a scale that I care about. I spend almost zero maintenance time per month, less than 10 minutes per day interacting with it.
It's also proved an excellent toy for me to constantly retool and play with new languages, frameworks, and databases. Couldn't be happier.
Absolutely - rather predictably, but only within the segment I use. If you're an HFT trader you can't win. But if you have patterns you've noticed, can act on and encode... well quite frankly it's incredibly consistent on baskets of stocks (not daily), but very much based on a variety of characteristics.
Over the last year I've met two to three traders (as in big bank) who literally do this for weeks.
It's also proved an excellent toy for me to constantly retool and play with new languages, frameworks, and databases. Couldn't be happier.