Object Tracker 1

[Alan Lowbands]

Hi,
I was hoping someone may be able to help.
I need to find a way to track small objects in long grass.
The tag or transmitter has to be able to be mounted on a snails shell and needs to be detectable within a few metres.
I have looked at RFID and NFC tags but there either too big or don't have the range.
As a mechanical engineer I haven't a clue if this is possible or not.
I'm not mad, it's a school science project.

Any help would be really appreciated.

thanks
Alan

 

[IRstuff]

"don't they already leave a trail"

But, can you tell which trail belongs to which snail?

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[Alan Lowbands]

IRstuff (Aerospace) 20 Jun 18 14:39

"don't they already leave a trail"

But, can you tell which trail belongs to which snail?

-------------------------------------------------------------------------------------------

Ever wish you hadn't started something lol.

 

[MacGyverS2000]

With a little image processing you can

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[IRstuff]

Even then, you'd still need to ID the snails to begin with, so whatever markings you use to distinguish initially could be image processed directly.

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[Alan Lowbands]

Is there anything else that could be used?
It just needs to blip when you get near them. Nearer you get, the loader the blips :/
I thought of painting them with metallic paint and use a metal detector but can't see working.
The only other thing I could think of was making something like a metal detector to get closer so the rfid things might work.
The painting to id them would be an option if they didn't vanish into the long grass.
There has to be something out there lol

 

[MacGyverS2000]

You're always going to run into the power problem. You either need transmitters that throw out a lot of power, or receivers that can recognize a tiny amount of it. The former is difficult to do with a passive system, and the latter is difficult to do with accuracy (i.e., "this is a snail, not a neutrino decay").

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[Alan Lowbands]

So lets say I need a receiver that can work with a tiny amount of power.
It would need it to be hand held (smallish) and on a handle that keeps it say 2" off the ground.
Where would the power come from to activate the passive tag?
How difficult would it be for a beginner to make this work?
Should I leave home now and come back when she's 21?

 

[IRstuff]

> If you use certain types of RFID tag, you can get very long ranges:

https://www.phaseivengr.com/wireles...sors/about-ultra-long-range-uhf-rfid-sensors/

> The power for the tag comes from the scanner; the receiver rectifies the RF and generates sufficient DC to run its operations


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[3DDave]

Again, how big are the snails?

RFID tags are typically at least an inch square. Smaller, non-ID RF tags are about 1/3 that area.

 

[Alan Lowbands]

It would have to be smaller than an inch.
The tag doesn't need to carry any information other than its serial or id number.
As for the size of the snails, as big as we can get

 

[MacGyverS2000]

For passive tags, the transceiver provides the power. However, conversion efficiency is extremely low, so you need to get close, provide high receiver gain (which is noisy from a signal standpoint), or both.

Dan - Owner

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[Alan Lowbands]

Is there any other solution to this?
I'm not bothered about reading any data just finding there location.
Identification could be done by painting the shell as suggested.

 

[MacGyverS2000]

RF solution? Unlikely, physics being what they are and all. Power transfer is a bitch, and it only gets worse as you decrease size (from both an energy storage and an antenna size/sensitivity standpoint).

Dan - Owner

http://www.Hi-TecDesigns.com

 

[VEBill]

OP: "...just finding [their] location."

As 3DDave already mentioned, "...retroreflective tape would work on even small items..."

The sort of reflective tape that contains zillions of tiny retro-reflectors. Super bright reflections back in the direction towards the light source.

 

[waross]

How about this technology? Used to track small frogs in the wild. Might be too expensive for a 12 year olds science project though.

Link

The harmonic direction finder’s range is also limited, to under 15 meters, so it isn’t ideal for highly mobile species.

One size does not fit all. This may work for snails but not as good for sheep.


Bill
--------------------
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