With some servos and a thermometer you could automate mixing the correct temperature and turning the taps off; the future is now
homeassistant
Home Assistant is open source home automation that puts local control and privacy first. Powered by a worldwide community of tinkerers and DIY enthusiasts. Perfect to run on a Raspberry Pi or a local server. Available for free at home-assistant.io
Make it happen OP!
I guess that's cool.
Why not just set a timer? Does the bath not fill at the same rate every time?
Yes and no. Your water supplier can alter the pressure of your water. This happens, for example, when there is a water shortage. But mostly yes.
Well because that would be a boring post on the Home Automation community, and also because I can use automation so I don't have to do that, kinda the point of automation.
I'll level with you, when I get my quiet time before a bath, I smoke just a little bit of weed. It makes remembering to do stuff just a little bit less likely. This automation means I don't have to remember to do a fucking thing.