A purpose-built instrument for a single, specific problem. Cinematographer Ruben Woodin Dechamps needed to run a vintage 16mm camera in a difficult environment for a site-specific shoot, so I built him a frequency monitor that mounts directly onto the camera body.
It reads the values, shows them on an onboard screen, and transmits them over Bluetooth to a phone for monitoring from a distance. Small, rugged, and made for exactly one job — the kind of constraint I like.