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
http://www.ebay.com/itm/2-2-inch-2-2-...
(mine was only $4.50 but the above was the cheapest found on Ebay just now)
DS3231 RTC
http://www.ebay.com/itm/Arduino-DS323...
Arduino Pro Mini 3.3V
http://www.ebay.com/itm/FTDI-Adapter-...
Code is here: https://www.dropbox.com/s/da4dicfagvo...