Quantity   Component name
1 × Atmega328P-MU Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers
1 × TMP112 0,5°C onboard temperature sensor
1 × DS3231M (SOIC8 package) Clock and Timer ICs / Real-Time Clocks
1 × M24M02 Memory ICs / EEPROMs, alternatives are e.g. 24LC512, 24AA512, ...
1 × Keystone 3012 button cell holder for CR16XX cells
1 × LED, size 0603 whatever color you like
1 × push button reset button, eBay.
8 × SMT resistors, size 0603 5% (1%), values see circuit diagram
4 × SMT capacitors, 3x size 0603, 1x size 1206 X7R or N0G, values see circuit diagram
1 × PCB 3 boards for 3-5USD@ https://oshpark.com/shared_projects/WRX8T4Oo