Hey, I just signed up..this forum is damn cool! Im on a couple of strongman/powerlifting forums (my other hobby) but I cant believe I never though of finding a good science forum given that Ive persued a degree in practically every field (math, physics, bio, ect) but have yet to actually recieve one in any of them....120+ credits and nothing to show for it.

 

Anyway, I was just wondering if anyone knew of a device that consists of a sensor and some kind of object that, when sensed by the sensor, triggers an electrical response. Sort of like a motion detector but instead of responding to motion, it responds to its accompanying object. If there is no exact device out there does anyone have any ideas of how one can be made?

 

-Thanks

like a Tracer colar/tag or the RFID tags or even a lo-jack?

 

that sort of thing?

Or a magnet and electromagnet like used on bicycle computers....

like a Tracer colar/tag or the RFID tags or even a lo-jack?

 

that sort of thing?

 

Im not sure what any of those are.

 

The bicycle computer wouldnt work becouse the proximity necessary to have it activate is too small.

 

I would need the sensor to pick up the presence of the object within a larger radius...say 5-10 meters.

 

It should work exactly like a motion detector....like the kind wired to security lights...except instead of detecting a person alone, they would need to have some object with them to activate the response and as soon as the object moves outside the given radius the response would cease.

Hi.

I have somewhere among my spider webs, a gadget that I have never used, it is smaller than a pack of cigarettes, divided in two sections.

One is a transmitter and the other a receiver.

The transmitter half is meant to be attached to a kid (or a briefcase) and you keep the receiver in your pocket.

If the distance between the halves exceeds ~5 metres, reception is lost and the alarm sounds.

When not in use, one half attaches to the other turning both off.

Miguel

Yeah that would work! Do you know what its called or where I can get one?

 

Also, do you know by what principal the device works? (i.e radio, IR)

radio.

It's probably a very low power radio transmitter, and receiver... with the signal stength required to be just about that at 5m...

it`s a micro-watt FM carrier that when out of range drops below the squelch level, re-biases the base of a transtistor and triggers enough current to activate the alarm.

 

nothing fancy

Hi Gene. I sent you a private message but unsure if I did it right.

Miguel

externet @ inorbit . com