Do the raider's arithmetic. A C4 eats two pieces of tech trash; the sensor that hears it eats one. Half a charge's circuitry to know about every charge is one of the better trades at the Level 2 bench, and the blueprint costs little scrap.
The catch is what sits around it. The sensor only passes power on, so it needs a feed from a battery and something at its output. A smart alarm reaches your phone but takes another piece of tech trash. A siren light costs only frags at a Level 1 bench and warns whoever is already online.
Craft it the evening your base gets a loot room worth raiding, not the morning after the first raid. A sensor wired into a base that has already been opened tells you nothing you don't already know.
Questions
Seismic Sensor ×10: how many resources?
High Quality Metal ×30, Tech Trash ×10.
Which workbench does Seismic Sensor need?
Workbench level 2.
How long does Seismic Sensor take to craft?
25 s for one, every step included.
How much scrap does researching Seismic Sensor take?
