You can use two 555 ICs instead of the 556. The first timer provides a delay of 7.5 minutes and the divided outputs give a delay of 15 min, 30 min, 1 hour and 2 hours respectively. The second timer is ...

Starting with the 556 timer, and inspired by the old spring-and-jumper kits of the past, [grandalf]’s “556 on a Proto Shield” project evolved into a creation they call the Retro Shield.

Starting with the 556 timer, and inspired by the old spring-and-jumper kits of the past, [grandalf]’s “556 on a Proto Shield” project evolved into a creation they call the Retro Shield.