Realtime Clock in Arduino: Difference between revisions
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Power draw for Arduino on standby on 3.7V is about 20ma. So uses about 1.5Whr every 24 hours. | Power draw for Arduino on standby on 3.7V is about 20ma. So uses about 1.5Whr every 24 hours. | ||
A solid state relay will draw .1W on the driving side, but the load side loses significant power (1V drop). 20W loss when running a 20A load - significant through the day. | |||
May want a mechanical relay. | |||
Revision as of 06:49, 19 March 2021
Internal
Arduino has an internal clock. Is shut down if Arduino loses power. Can use 3.7 battery for power. Library is RTC.h.
https://www.arduino.cc/en/Reference/RTC
Power draw for Arduino on standby on 3.7V is about 20ma. So uses about 1.5Whr every 24 hours.
A solid state relay will draw .1W on the driving side, but the load side loses significant power (1V drop). 20W loss when running a 20A load - significant through the day.
May want a mechanical relay.
External
Module is cheap - [1]