Arduino – Simple Bedside Clock

As a fan of things that ‘just work’, this quick project solved a night time problem very well. To see the time on waking in the middle of the night.
No bells and whistles, it’s clean, concise and accurate to something like 1 second a year (much better than some similar RTC modules).
The temperature sensor is inbuilt to the DS3231, a handy feature and for approx 73 cents they even arrive with the CR2032 battery on them !
The 150ohm resistor limits brightness to be great at night for the eyes and limits the current – this uses just an average of 16mA, when measured with a multimeter.

Example parts sources:
TFT screen×320-ILI9341-51-AVR-STM32-ARM-PIC-/182350166341
(mine was only $4.50 but the above was the cheapest found on Ebay just now)
DS3231 RTC
Arduino Pro Mini 3.3V

Code is here:

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