Every year, Shelly the tortoise gets lost or manages to escape the garden.
It can take days to find her. I would like to build a locating device so
that I can track her down.
The basic requirements a

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?

TIA
Floatything (an escapee from uk.rec.sailing)

On Sun, 05 Mar 2006 11:20:29 GMT, "Floatything"
wrote:

Every year, Shelly the tortoise gets lost or manages to escape the garden.
It can take days to find her. I would like to build a locating device so
that I can track her down.
The basic requirements a

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?

TIA
Floatything (an escapee from uk.rec.sailing)

You might be interested in this kit from Ten Tec:
http://radio.tentec.com/kits/Accessory it is #1059 which radiates on
the FM broadcast band (88-108 mHz).

Howard

wrote in message
...
On Sun, 05 Mar 2006 11:20:29 GMT, "Floatything"
wrote:

Every year, Shelly the tortoise gets lost or manages to escape the
garden.
It can take days to find her. I would like to build a locating device so
that I can track her down.
The basic requirements a

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?

TIA
Floatything (an escapee from uk.rec.sailing)

You might be interested in this kit from Ten Tec:
http://radio.tentec.com/kits/Accessory it is #1059 which radiates on
the FM broadcast band (88-108 mHz).

Howard

Thanks - that's excellent Howard - it looks just the job. So all I need to
know now are the 'basics of direction finding'.. I presume I need to wave
the aerial about a bit until I get a stronger beep beep? (tell me I'm on the
right track? or is there some magic method to homing in on a beeping
reptile?

Floatything

"Floatything" wrote ...
Thanks - that's excellent Howard - it looks just the
job. So all I need to know now are the 'basics of
direction finding'.. I presume I need to wave the
aerial about a bit until I get a stronger beep beep?
(tell me I'm on the right track? or is there some magic
method to homing in on a beeping reptile?

The basics are a directional antenna and triangulation.
Do they still sell those RDF things for watercraft which
use a loop antenna? Same principle. A directional FM
antenna (like a yagi) which you can rotate to find the
strongest signal. Then move a distance and plot the
max signal as another line on the map. Assuming your
tortise isn't moving that fast, go the the "X" on the map
and retrieve your reptile.

There are lots of miniature FM transmitter kits available,
but beware that the range of many (most?) of those
devices may be limited to a range where you could
just locate your creature by sight (particularly those
which can be powered by photo-voltaic cells :-)

Note that you could also use preassembled GPS and
cell-phone modules (like those available from one of
my favorite toy-shops: www.sparkfun.com) and create
a box which you can call on your phone and will report
the tortise's current location. You could have the first
tortise-lojack on the planet! :-)

It is rumored that many high-value items (besides autos)
have this kind of secret locator transponder devices
installed in them.

See the attached, might be what you need.

http://thecatlocator.com/locator/intro.html

Floatything wrote:

Every year, Shelly the tortoise gets lost or manages to escape the garden.
It can take days to find her. I would like to build a locating device so
that I can track her down.
The basic requirements a

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?

TIA
Floatything (an escapee from uk.rec.sailing)





--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

I forgot to mention, you can buy just the transmitter and construct your
own receiver. The transmitter is FCC certified and I was able to look up
the specs on the www.fcc.goc website under OET equipment certification.

**THE-RFI-EMI-GUY** wrote:

See the attached, might be what you need.

http://thecatlocator.com/locator/intro.html

Floatything wrote:

Every year, Shelly the tortoise gets lost or manages to escape the
garden.
It can take days to find her. I would like to build a locating
device so
that I can track her down.
The basic requirements a

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic
soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?

TIA
Floatything (an escapee from uk.rec.sailing)






--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

Richard Crowley wrote:
"Floatything" wrote ...

Thanks - that's excellent Howard - it looks just the job. So all I
need to know now are the 'basics of direction finding'.. I presume I
need to wave the aerial about a bit until I get a stronger beep beep?
(tell me I'm on the right track? or is there some magic method to
homing in on a beeping reptile?


The basics are a directional antenna and triangulation.
Do they still sell those RDF things for watercraft which
use a loop antenna? Same principle. A directional FM
antenna (like a yagi) which you can rotate to find the strongest signal.
Then move a distance and plot the
max signal as another line on the map. Assuming your
tortise isn't moving that fast, go the the "X" on the map
and retrieve your reptile.

There are lots of miniature FM transmitter kits available,
but beware that the range of many (most?) of those
devices may be limited to a range where you could
just locate your creature by sight (particularly those
which can be powered by photo-voltaic cells :-)

Note that you could also use preassembled GPS and
cell-phone modules (like those available from one of
my favorite toy-shops: www.sparkfun.com) and create
a box which you can call on your phone and will report
the tortise's current location. You could have the first
tortise-lojack on the planet! :-)

It is rumored that many high-value items (besides autos)
have this kind of secret locator transponder devices installed in them.

The only problem I see with this is that you will have to change the
battery on the tortoise pretty regularly. If you have just the receiver
on the tortoise and only go into a 'wake-up' condition upon receipt of a
signal from your transmitter you will get extended life. If the receiver
then triggers a beeper that you listen for you'll get good life out of a
battery and run less risk of the battery being flat just when you want
to go find the beast. Since the roaming range is fairly limited the
audible range shouldn't pose a problem.

Cheers.

Ken

Fastenen one of those little tinycell phones to his back,when you loose
him,give him a ringy dingy..when his phone rings ,you got him.. Old Ham

Gee, put APRS on 'er and just go to findu and look @ the map (;-)

Just kidding. That LoCATor is pretty steep $$ wise for a turtle...and it
looks like it may be in the 220 band...215-235. Nifty beam though - rather
sturdy construction.

73, Steve, K9DCI


"Richard Crowley" wrote in message
...
"Floatything" wrote ...
Thanks - that's excellent Howard - it looks just the
job. So all I need to know now are the 'basics of
direction finding'.. I presume I need to wave the
aerial about a bit until I get a stronger beep beep?
(tell me I'm on the right track? or is there some magic
method to homing in on a beeping reptile?

The basics are a directional antenna and triangulation.
Do they still sell those RDF things for watercraft which
use a loop antenna? Same principle. A directional FM
antenna (like a yagi) which you can rotate to find the
strongest signal. Then move a distance and plot the
max signal as another line on the map. Assuming your
tortise isn't moving that fast, go the the "X" on the map
and retrieve your reptile.

There are lots of miniature FM transmitter kits available,
but beware that the range of many (most?) of those
devices may be limited to a range where you could
just locate your creature by sight (particularly those
which can be powered by photo-voltaic cells :-)

Note that you could also use preassembled GPS and
cell-phone modules (like those available from one of
my favorite toy-shops: www.sparkfun.com) and create
a box which you can call on your phone and will report
the tortise's current location. You could have the first
tortise-lojack on the planet! :-)

It is rumored that many high-value items (besides autos)
have this kind of secret locator transponder devices
installed in them.