Quantity   Component name
1 × attiny10 Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers
1 × pull up resistor, 500k You can use internal pullups too, but I thought an external one might save a little power.
1 × CR2032 Batteries and Battery Accessories / Batteries
1 × CR2032 Holder
1 × Piezo Buzzer Don't be like me -- get one that works well at 3V. Salvage a greeting card if you need.
1 × Pushbutton Intermittent type