tracking devices

[psi20]

I read about a school doing that. How does it work? How can I make my own tracking device? Is it related to the GPS system in cars?

[The Rebel]

I read about a school doing that. How does it work? How can I make my own tracking device? Is it related to the GPS system in cars?

 

You need to be a bit more definitive in what type of tracking device you're after.

 

There is GPS tracking that positions you on the earth, but more locally there are magnetic trackers or more recently optcial trackers.

 

The magnetic trackers work on a transmitter that sends electrical pulses using three coils positioned in x, y and z. A receiver detects the strengths of these pulses at certain times to determine where the receiver is with respect to the transmitter. More modern trackers are using optics whereby the moving object is covered in emitting optical devices which are in a known 3D matrix, received by optical sensors.

[psi20]

How far can they track?

[Edward]

I read about a school doing that.

Are you reffering to

http://edition.cnn.com/2005/EDUCATION/02/17/tracking.students.ap/ if so it is preformed quite simply RFID tags transmit a weak radio signal of a 4 digit code readable olny within a few feet and when the tag gets close to a reciver the reciver recoginises the signal and the rest is software.

[psi20]

How about something that can track over 1-mile diameter?

[Molotov]

You would need a device that is capable of connecting to the GPS satellites, processing this data, then sending it via radiowaves to a tracking computer of some sorts.

[swansont]

You would need a device that is capable of connecting to the GPS satellites, processing this data, then sending it via radiowaves to a tracking computer of some sorts.

 

Connecting with GPS is trivial, since GPS sends out the data. All you need is a receiver for that. Then a transmitter, like a cell phone or equivalent, to relay the data.

 

The onstar service (of GM, I think) basically does this.

 

You could put in a can of coca-cola

[RICHARDBATTY]

You can get data log types if you just want to know an objects movements but you need periodic access to the object to get at the data. These are gps based and record a set of coordinates at set time intervals.