RFID / laser project

[kash791]

Hi,

I need to some kind of sensors/tags which can be placed outdoor. The same needs to be read  from about 25 m. (There will be need of setting multiple sensors in proximity, so the reader had to be a pin point and accurate system.)

On reading it should open particular pdf file on computer.

Edited January 18, 2018 by kash791

[Frank]

Billboard size qr-codes?

Does this need to be usable by anyone or someone using special equipment?  Smaller qr-codes and magnifying lens?  Laser might illuminate the code.

RFID are radio frequency waves and lasers are light waves, not really compatible.

 

[kash791]

Not bill board size but actually small may be few inch size.. And readable/sensed from 25m using another device.. Which then can trigger a PC to open a pdf file..

[Frank]

The extra optical zoom lens on a smartphone (plus digital zoom) isn't enough?

[Strange]

Sounds like a job for Bluetooth beacons. (RFID doesn’t have enough ugh range)

[kash791]

Hi Strange, but how can i have 100 bluetooth beacons.  i need to place 100 such sensors in about 100 ft area. and need to read/activate anyone at a time, the one selected should in turn open its respective pdf file on computer.

 

[Strange]

17 minutes ago, kash791 said:

Hi Strange, but how can i have 100 bluetooth beacons. 

How can you not have them? Apart from cost?

I guess the code running on the computer that is detecting them and opening the appropriate file will need to determine the correct one by choosing the strongest signal from those present. This is the sort of thing beacons are used for in shops, museums and art galleries.

Do you actually need sensors/beacons over the entire area? How about using something like two or three ultrasound sources in the corners and use them to triangulate the position of the computer.

Without knowing what you are trying to achieve, it is hard to say what solutions might work.

[swansont]

1 hour ago, kash791 said:

Hi Strange, but how can i have 100 bluetooth beacons.  i need to place 100 such sensors in about 100 ft area. and need to read/activate anyone at a time, the one selected should in turn open its respective pdf file on computer.

If you have 100 of them in a 30 m (100 ft)  area presumably you mean 30 m x 30 m, if you need to read them from 25 m away, does this mean you are outside of this area? Do you have line-of-sight? 

Active RFID at UHF have rages up to ~100m
https://www.impinj.com/about-rfid/types-of-rfid-systems/

[EdEarl]

Bluetooth 5 support 40-400m distances. Each connection is based on a 48-bit code of each device, and spread spectrum is used to assure connections do not interfere with one another. Theoretically it is possible to select a device by its code from billions nearby. One computer can communicate with seven other Bluetooth devices at a time.

[Frank]

Telephoto lens, smartphone, small qr-code target opens pdf.

No batteries in target, cheap, simple, no coding or app needed...

 

[swansont]

2 hours ago, Frank said:

Telephoto lens, smartphone, small qr-code target opens pdf.

No batteries in target, cheap, simple, no coding or app needed...

 

Assumes line-of-sight and proper orientation with respect to the QR code.

[Frank]

43 minutes ago, swansont said:

Assumes line-of-sight and proper orientation with respect to the QR code.

True.  But qr-codes posters are cheap to print, so can be oriented/positioned. as needed.  If line of sight isn't needed, then a simple geolocation map can be used to display targets based on current position in a specialized app.  Click on the target (could even be merged with camera view and phone orientation and position to display virtual targets).  Update the map as needed.  Hard to know without knowing the actual application.

 

[kash791]

Swansont,

 

Hi, Yes i do have a line of sight and i would standing out of the area.

HI, Frank,

 

Actually what i want to build is a sand model of a map on ground. i want to point a laser/rf reader or qr reader or something else to a particular feature like a town and data of the town comes up on computer screen. when i point it at a different feature then details of that feture needs to come on screen.

 

thanks

[Frank]

Interesting.  So Qr-codes might mess with the aesthetics?

Laser pointer could activate (or even power) a radio transmission (blue-tooth or RFID) as others mentioned.  Not so great if many people are using the model simultaneously.

Are viewer(s) limited to the perimeter or to an observation area?  Or free to roam in the model?  Might make some things easier if the vantage point is known.  Use the QR-codes at the observation point to load up a map of where things are relative the particular qr-code?  RFID could function in a similar way.

 

 

[kash791]

No the QR code won't spoil the aesthetics. Viewers aren't limited to the perimeter. They can travrl about the model.  However the Triggering of the QR code will be done by only one viewer.

[Strange]

So how about a photodetector at each point of interest. This can detect the light from the laser pointer and be used to trigger the display of the appropriate file.

Edited January 20, 2018 by Strange

[kash791]

Strange,

 

Photo detectors would need to be wired. So more difficult to manage.