Star Trek: 10 Things You Didn't Know About Tricorders
7. Uses, Misuses, And Abuses
There's a big red bit labelled 'EMRG' on the TR-560, 580, and 590 tricorder models. You might think this was to send a distress call, but, according to the Star Trek: The Next Generation Technical Manual, it is actually the "emergency 'dump everything to the ship' button". Pressing it will send the tricorder's entire memory up to a range of 40,000km, disabling all scanning functions for about 0.875 seconds and draining half the power too.
Aside from ensuring Starfleet has all your data before you die, there are plenty of things you can do with a standard tricorder. Packed full of mechanical, electromagnetic, and subspace sensors, all tricorders from the start of TNG to at least Star Trek: Nemesis had three input settings: GEO(LOGICAL), BIO(LOGICAL), and MET(EROLOGICAL) for all your scanning needs. Tricorders can't detect neutrino emissions, however, so connect to a VISOR instead.
The Star Trek: Voyager Technical Manual gives a rather blunt description of how to use your tricorder: "Simply point [it] at whatever it is you want to study." If you're after exact detail on how to use one to cause localised seismic disruptions or anaesthetise a patient, then check out The Starfleet Survival Guide. Note that to really mess with a tricorder, you'll need a thoron generator.