Best posts made by tochinet

A few "reality checks" with ADCs :

• The precision of the ADC is limited to 0.1% at full scale (1024). This means that when measuring smaller values, it's less precise. For example, when measuring 1/10 of the reference, your precision is down to 1% already.
• Analog noise is usually in the range of 10mV is your circuit is carefully designed. Similar to above, it has a bigger effect on small values, but also on smaller references (1.1V is 3x more sensible to noise than 3.3V). Add a 10nF capacity in parallel to your 330k for better resilience.
• ADC is slow and needs time to calculate. Wait enough time between changing parameters and reading value (the Ardunio routines don't).

I'd suggest you do a for() loop of 20x reading your ADC, and see the variation : mean(), std() and trend (for example last 5 - first 5). It could learn you a few things.

@rozpruwacz I can guarantee you that the IDE will NOT link all the libraries in every project. I have many, and they would never fit in one 328P memory. Even the parts of libraries that are not used do not get in.

That said, there are many "memory eaters" in libraries, so you should only consider using one if you really need it.

A second point of attention is using floats. They are deadly for memory, because the 328p is not able to calculate with floats natively. Division is already huge, but if you use any sin or tan, kB are used.

A third eater is ... objects. When you create an object (from a library), every part of it is created. So if it done according to the good old rules, it starts bay uselessly copying the parameters of the constructor into its internal variables ... that maybe won't ever change.

Strings are also eating a lot of memory. Both in creation and in manipulation.

To see what eats your memory, start from an empty sketch setup+loop, and add each part of your sketch (in a compilable way) step by step. You could be surprised of where the biggest memory eaters are.

@zboblamont I also have a quite complex and too expensive system (heatpump, solar panels, RF devices) for my (floor) heating, and indeed you did the right thing : insulation is the key. Your (and every user's) goal is to spend less, Honeywell's goal is to sell you their stuff (sales) and lead you into believing that it was the right choice (marketing). So if you want to get additional benefits, you can also ... double check your air tighness and ventilation, and monitor your electricity bill. Not sure if PV is an interesting alternative where you live.

One of the reason of the lack of feedback is that your OP is not really a (simple) question. Not sure what you ask opinion on, and you already did your homework. A second reason is ... summer.