Using a dual 555 CMOS this very useful circuit on the bench was found in the July 1998 Electronics Now magazine. The circuit is battery powered.
Circuits similar to this appear elsewhere in this section. The transistors can be BC549 (low...
This circuit indicates when a rain is acidic by monitoring its pH. The circuit is from a 90s RE...
In a microprocessor project (shield) for control applications, a triggered clock can be useful....