Reverse-engineering Ahmed Mohamed's Clock and Ourselves
The point is the swap over to battery power is near trivial, and as I said most clock chips have alarm functions built in that could be used for most any kind of event trigger (buzzer, bell, etc. after proper conditioning).
When you’re learning or in training/practicing, you don’t do it with explosives installed.
There is just too much crap there for “just a clock.” For it to be “just a digital clock” it would have to be the technology like back when I was working on electronic equipment in the 70s.
Gaffer, it IS a 1970s clock. It’s a late 1970s or early 1980s Micronta (Radio Shack) alarm clock!