Is there such a thing as a programmable clock?
i.e. setting a time, and then reading it back.

I’d like to trigger a relay at a certain time, but I can’t find the component to do so…

Any ideas?


Maxim-ic makes several real time clock chips that will do what you want. They have serveral different interfaces available SPI and 1-wire serial. Most require only a crystal and an optional lithium backup battery.

There are also examples in the playground. Search for RT clock.