Here is an interesting hobby circuit of a “crank” door bell! The circuit is built around a timer 555 and a musical piezo-buzzer. The circuit works off 9 volt battery supply. One 9volt PP3/6F22 compact ...

If you’re expecting an important visitor but you just have to step out for a moment, an electronic doorbell memory can come in handy so you can see whether someone rang while you were out. Of course, ...

The computing collection contains several schematics of the computer system X-66744, created by Samuel B. Williams and George Stibitz at Bell Telephone Laboratories in New York City. Williams and ...

We’d wager that, if you’re reading Hackaday, you’ve looked at more than a few circuit diagrams in your day. Maybe you’ve even converted a few of them over to a PCB. It’s a workflow that, at this point ...