Usually the business card itself is the reminder to get in contact with whoever gave it to you. But this is Hackaday, after all. This solar-powered card reminds the recipient to send [Dead Rat Productions] an email by beeping about every two hours, although the gist of that email may simply be begging them to make it stop, provided they didn’t just toss the thing in the garbage.

The full-on, working version of the card is not intended for everyone — mostly serious-looking A-list types that ooze wealth. Most of [Dead Rat Productions]’ pub mates will get an unpopulated version, which could be a fun afternoon for the right kind of recipient, of course.

That person would need a Seeed Studio Xiao SAMD21, a solar panel, plus some other components, like an energy-harvesting chip to keep the battery topped up. Of note, there is a coin cell holder that requires prying with a screwdriver to get the battery out, so there’s really no escaping the beeping without some work on their part. We rather like the artwork on this one, especially the fact that the coin cell sits inside the rat’s stomach. That’s a nice touch.