I'm planning a wifi thermostat to control room temperature andhave some questions:
The device would have the following modules:
- eInk display
- relay to control the boiler
- BMP280 to measure T (and humidity and pressure) of the room
- RTC module
- 1 cell 14500 battery with 3.7 V-s
few buttons to program
the MCU would be an ESP-12 module
an external webserver to collect data, set temperature, etc.
My idea is that the ESP-12 would be in deep sleep as much as it can. I couldn't use a wall plug and I need at least 8 months of working time.
(what I thnik) the easier part of the project is the following:
in every 5 minutes the ESP wakes up thanks to the RTC module to modem off mode, updates the system time and sets the next wake up time, measures the actual temperature and compares to the set temperature, sets the relay, updates the eInk display and goes back to deep sleep
in every 15 minutes ESP wakes up, turns its modem on, checks the desired temperature from the server, uploads the actual temperature, does the relay/RTC setting and than goes back to sleep
However I'm in doubt with the following: If I want to display the time (hh:mm) than the only way to do it is to wake up, set the display and go back to deep sleep in every minute?