So I'm trying to detect through Visual Basic 6.0 when a voltage change occurs on one of the pins of the serial/parallel port. The whole thing is pretty ...

Saleae logic analyzers seem to have it all: good sampling rates, convenient protocol decoding, and plenty of channels – but not a good way to set rising or falling-edge triggering. [James] found ...

This design shows how a piezoelectric transducer's acoustic output can be increased while minimizing the parts count and cost.