ATTiny85 Time and Date Logging

-ATTiny85 Time and Date Logging-
I'm currently doing a project where I'm putting a PIR Sensor to the ATTIny85 and when the PIR Sensor goes high the Attiny85 Logs the Time and Date

Can anybody help with this

Some questions arise:
Where do you get time and date from?
A RTC (Real Time Clock) might help. My recommendation: DS3231 (I2C) or DS3234 (SPI)

Where do you log the data to?
EEPROM might be an option, but there is only 512 bytes with ATtiny85. If you need more, writing data to SD card might be another option.

Maybe it can be done with an ATtiny85 but it might be tricky. You may run out of pins and SRAM (254 bytes only) pretty soon.

I recomend of of those DS3231 modules like this one.

they feature an additional AT23C32 eeprom with 32k. I use them with an ATTiny85 for temperatur logging. They use I2C, so just 2 pins needed on the ATTiny.