I will ignore OP response as its in defense of his product, which is very common for any developer in IT world. In addition, I have always found his responses to be quite condescending and sooner or later he brings up the topic of this being part-time, active job, family, etc. Quite frankly, that will work if his work is for free. It’s not. There’s a charge associated to it. With that comes responsibility, support and many other things.
To readers: Please feel free to continue using this product. I’ll start perhaps a separate dedicated thread where I’d like to educate readers on dangers of doing so. My logic is simple: you are avoiding a combined effort of many, many talented engineers and teams who have developed something - Nest/Ecobee taking into consideration many factors just for the benefit of using the motion sensor/open-close sensor provided temperature readings? Please look at this logically.
Those sensors either open-close or motion were geared/tested/constructed for that respective purpose. Let’s just say providing temperature readings is supplementary. The sensor providing it is and will be of the most rudimentary type.
In a house the biggest and cosliest and perhaps the ONLY mechanical item is your HVAC. They run into 5 figure mark for installation/configuration and very well touch 4 figure mark or high 3 figure if repairs are required. Instead of relying on collective wisdom with years of testing/engineering acumen/knowledge of Ecobee/Nest engineers if you’d prefer to keep that highly expensive unit (HVAC) under the control of 1 person who in his own admission is doing this like a hobby or part-time is up to you.
A set of 2 remote ecobee sensors cost no more than $79 USD. They are regularly updated, they have eons ahead in terms of sensor technology for detecting motion and accuracy of temperature in comparison to Samsung motion or open-close. There are numerous articles where they have opened and dissected to see quality and type of sensors in use - just check thru Google.
In terms of features - by carefully controlling the comfort settings per sensor coupled with Follow Me feature Ecobee stands heads and shoulder over any of these mom and pop side programs. Are you aware, its not just for record keeping that Ecobee requests user to provide data related to the home - like age of home, location, etc. Those data points are actually used to provide a comfort setting along with continuous energy savings. In fact, the proprietary algorithm of energy savings used by Ecobee is so exclusive they have it air gapped for security purposes? Now, you want to avoid all of that and depend on 1 person’s effort - well: best of luck.
Your HVAC is yours and thus what you do with it, i.e. how many times it just starts up/shuts down/etc. is dependent on 1 and only 1 thing: the thermostat. You are forcing that thermostat to now behave almost real-time with temperature on HOLD and in decimals: don’t you think logically you are taxing your HVAC unnecessarily? For what, to save $79? Again - please look at this logically.
Where I was involved in? My core focus area is micro-services and cloud. The programs we worked on was how to send tailored / custom programs into a thermostat which belongs to a cluster where certain standardized energy saving algorithms will not work. For example - a condo association in a city - XXX. They happen to have false stucco walls (we think) and low insulation. Then perhaps a more aggresive energy savings is required. Those fine tuned firmwire are hosted in specialized cloud clusters and using Chef we attempted to perform targeted release.
All of this and much, much more: you’d like to avoid and trust and believe on someone who in his own admission is doing this part-time?