I want to have a go at a temp monitoring project that I would monitor from an Android phone so am asking for advice.

Setting the scene. I run an alcohol still every 5-6 mths and would like to remotely monitor two temperatures to save me constantly jumping up and down to visit the laundry room where the still is running. The Still run time is about 7-8 hours, so a monitoring system would save some of the visits plus give me a new project to get my teeth into at a very moderate cost. Two full days are needed as I double distill.

I need one of the readings to go to one decimal place but the other could just be whole degrees. I also need to be able to set a high temp for each that would give a warning sound when reached. This would have to sound even if the phone was asleep.

I am pretty good at electronics, and have been a programmer, so that is a start! There is also no time pressure as I have just finished a run. 

I have done some reading, including other relevant posts in this thread, and think the route to take is to use wemos sensors with DS18B20 probes, monitored with OpenHAB on a cell phone. But what about going with Adafruit solutions?

If you have got this far, I would be grateful for ideas on the route to take. Keen on being able to follow detailed instructions from somewhere!