Breakdown of Стоило датчику сработать, как пожарные ответили на вызов.
на
on, at / by (transport) / to (a place) / to (in answer to)
ответить
to answer (perfective)
как
than (in 'no sooner ... than')
датчик
sensor
Questions & Answers about Стоило датчику сработать, как пожарные ответили на вызов.
Why is датчику in the dative case instead of the nominative?
This is required by the стоило ... как construction. The subject of the first action (the sensor) must take the dative case, and its action must be an infinitive (сработать). You can think of it literally as 'It only took for the sensor to go off, when...'
Does как mean 'how' here?
Not in this context. In the стоило ... как structure, как acts as a bridge to the second clause, behaving more like 'when' or 'than'. It emphasizes immediate succession: 'No sooner had the sensor gone off than the firefighters answered.'
What is the specific meaning of сработать? I know работать means 'to work'.
Adding the prefix с- to работать shifts the meaning from an ongoing process of working to the momentary, successful activation of a mechanism. For alarms, sensors, or traps, сработать specifically means 'to go off' or 'to trigger.'
Why does ответили take на вызов in the accusative case? Don't we usually use the dative case with this verb?
You use the bare dative case when you answer a person (for example, ответить маме). However, when you answer a thing or a concept, like a question, a letter, or an emergency call (вызов), Russian requires the preposition на plus the accusative case.