Do Wikia
Spider-Man uses a small electronic receiver to follow the signals of his tracers, ...
but eventually he modifies the tracers to emit a signal he can follow with his spider-sense so that he will be able to know whether or not he is in the proximity of the tracer
Também da Wikia
A teen Spider-Man invented his first Spider-Tracer to find Doctor Octopus. In those early times he invented a receiver device as well. Spider-Man eventually found out that changing the frequency emitted by the Tracers he could trace them with his Spider-sense.
Como para os outros que usam os traçadores
Besides Spider-Man, Daredevil can pick up the signal with his Radar Sense from the Spider-Tracers due to his heightened sense of hearing being able to hear the signal. Unlike Spider-Man, it is more difficult for Daredevil to follow the signal, as he must drown out all other sounds around him to maintain focus.
E então:
Using his resources at Parker Industries, Peter Parker built an improved version of the Spider-Tracer. He made it available for commercial use, having the option of being linked to a webware. The new spider-tracer featured a two-year battery life, was water-proof, and was super durable.