tracking device

[Dizzee]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

 

[John Tserkezis]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.

Something like a crystal oscillator with buffer (just supply 5v). Looks like
a smallish rectangular can with four pins (only three used, 5v in, gnd, and TTL
output).

Output goes to a loose wire.

Use a scanner tuned to listen to the carrier, and a directional antenna will
help with the direction.

A dipole will have two "blind" spots, a bit of triangulation will tell you
which of the two blind spots is the real direction.

 

[SioL]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

Tray Ramsey electronics, they've got a small tracker for rocket models.

SioL

 

[John Larkin]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

What we want is a CatCam, a collar-mounted, RF-linked, IR-illuminated
camera so we can see what Marge does on her nights out. (No, she's
been fixed, so we don't expect to see *that*)

John

 

[Paul Hovnanian P.E.]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

Get a dog.

 

[Fred Bloggs]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

There a kiddie GPS locators for under $50- price is dropping everday-
these are wristwatch assemblies- adapt one of these.

 

[Bob Thomas]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

If your email address is valid I sent you an email to open the topic.
I have (with the help of some here and a collaborator) built just what
you are asking for, a collar suitable for an adult cat to wear that
allows you to track/find the cat, within reason.

If your email was not correct, then post one here with a good address,
I get so much spam as it is I won't put my real email addr on here any
more.

The technology is really pretty easy, it's the form factor and size
that is the real challenge, not to mention battery life, the hardest
of the problem to beat.

If this is for your personal/cat use, I will help you all I can, there
is no charge, I have not attempted to make this a commercial product,
at least not yet so I am not charging anything to the few I have
helped build one of these.

 

[Bob Thomas]

Something like a crystal oscillator with buffer (just supply 5v). Looks like
a smallish rectangular can with four pins (only three used, 5v in, gnd, and TTL
output).

Output goes to a loose wire.

Use a scanner tuned to listen to the carrier, and a directional antenna will
help with the direction.

A dipole will have two "blind" spots, a bit of triangulation will tell you
which of the two blind spots is the real direction.

RDF (Radio Direction Finding or "Fox Hunting") is the right approach,
however, in what you describe the battery life for a battery a cat can
carry would be under a day, believe I know from first hand experience
, that is, transmitting at the legal max power for non-licensed
public frequencies.

The Tracker part is the not hard part (at least not making one), it's
the collars form factor, size, and weight that is 1/2 the battle, the
other half is battery life.

Everything is worse case, from lack of an antenna ground plane, to the
antenna positioning, the power you can transmit, the practical weight
a cat can deal with, the frequencies you can use, to the places cats
hang out, like under parked cars, behind bushes, buildings, under
houses even.

Directional antenna (yagi's), doppler, and TDOA (Time Delay on
Arrival) are the core RDF approaches, all have significant drawbacks
for this application, but TDOA has worked out to be the most practical
for me. Using the "body-block" a lot of times you can resolve the
direction 0/180 without the triangulation dance, if you have a signal
strength reading, which is also good for distinguishing reflections
from the real source signal.

 

[Bob Thomas]

Tray Ramsey electronics, they've got a small tracker for rocket models.

SioL

That was one of the first things I looked at when I needed a cat
tracker, the Ramsey Rocket tracker will not work for a number of
reasons unfortunately, however, the Ramsey "FoxHunter" TDOA Radio
Direction Finder is a great tracker once you get a little practice in.

It's priced a little more than some of the other TDOA RDF units, but I
have one of each of the kits for TDOA's that I have found for sale and
the Ramsey unit is by far the best.

A simple bow-tie TDOA can be picked up for about 50 bucks last time I
looked and I made one from scratch for about 10 bucks in parts from a
public domain Radio Elections Schematic that is posted all over the
place in fox-hunter sites on the web.

 

[Bob Thomas]

There a kiddie GPS locators for under $50- price is dropping everday-
these are wristwatch assemblies- adapt one of these.

Could you by any chance post a link to a gps unit in that price range?

I have look at a LOT of gps tracker devices and have never seen
anything in that price range except when it required a monthly service
fee, that ranged from $29.95 - 59.95 a month, and some even had a per
find additional charge. I don't doubt you, I just say this so you
don't think I am too lazy to look it up myself, I have looked and
looked and looked...

The other thing, at least of the ones I can find, is that they are
pretty big, even accounting for the case and hardened parts, they did
not look like you could break it down small enough for a cat.

The other issue with the GPS units is you typically need two things to
work, one, the device has to "see" the sky to get the GPS fix, and it
has to "see" a cell network to communicate the location information.
There is one that just uses the cell system to get it's fix, at least
that takes out one logistical issue but they only operate out of a few
major cities and nearby surrounding area's.

For people wanting to be found and cars this is not as big a problem,
however, for a cat it might be, I still think GPS a very attractive
approach, you could eliminate the need for the cell and a service
company by transmitting the fix from the collar, just the range would
be limited to 1/8-1/4 mile at best.

Woz (of Apple fame) is sinking some major dollars in to an inexpensive
"object" tracking system where one of the goals is that the part that
gets tracked, in this case the part the cat would wear, is about the
size of a typical army dog tag, and these tags apparently will also
operate peer-to-peer and peer-to-host, allowing them to form extended
networks where the object is not in cell range but in the peer-to-peer
network range.

He is thinking of everything from wallets, even credit cards, pets,
people, cars, bikes, you name it. However, there is no time line I
have found and it may be years out, I can't seem to find anything but
a mention here and there about it.

Anyway, if you have any links to small GPS devices, for any purpose,
kids or not in that price range I would greatly appreciate it is you
would post one or more.

Thanks.

 

[Rich Grise]

Does anyone have a circuit diag. for a small tracking device.
or point me in the direction of some publication or web sites.
I would like to make a short range (100-200m) for... and I know it's a bit
sad... my cat.
thanks

Don't worry. It'll come home when it gets hungry.

 

[Bob Thomas]

Your email address bounced...

 

[Roger Gt]

: On Thu, 17 Jun 2004 23:38:33 +1000, John Tserkezis
:
: >Dizzee wrote:
: >> Does anyone have a circuit diag. for a small tracking device.
: >> or point me in the direction of some publication or web
sites.
: >> I would like to make a short range (100-200m) for... and I
know it's a bit
: >> sad... my cat.
: > Something like a crystal oscillator with buffer (just supply
5v). Looks like
: >a smallish rectangular can with four pins (only three used, 5v
in, gnd, and TTL
: >output).
: > Output goes to a loose wire.
: > Use a scanner tuned to listen to the carrier, and a
directional antenna will
: >help with the direction.
: > A dipole will have two "blind" spots, a bit of triangulation
will tell you
: >which of the two blind spots is the real direction.
:
: RDF (Radio Direction Finding or "Fox Hunting") is the right
approach,
: however, in what you describe the battery life for a battery a
cat can
: carry would be under a day, believe I know from first hand
experience
: , that is, transmitting at the legal max power for
non-licensed
: public frequencies.

Actually a small pulse at 400 to 500 mS intervals is enough to
track. A 100 mW signal will handle the range, and with a 50 mS
pulse the average power is less than 10mW. Most small batteries
like a AAA will last quite a while at that poser level. Maybe
even several days.

Three AAA cells should do it, and at 560mA and a load of 15mW
total, the batter8ies will last at least 48 hours. Maybe a little
more.
The frequency should be picked with an eye toward low
interference and easy access to a receiver. If you use a small
short-wave receiver 10 meters is pretty quiet now. (sun spot cycle
near low) so it would be pretty useful and an antenna can be
pretty short, just wire in the harness the cat wears. Tuning the
antenna with a bit of inductance will improve the range, you'll
have to experiment.

Good luck, sounds like a fun project!

:
: Everything is worse case, from lack of an antenna ground plane,
to the
: antenna positioning, the power you can transmit, the practical
weight
: a cat can deal with, the frequencies you can use, to the places
cats
: hang out, like under parked cars, behind bushes, buildings,
under
: houses even.
:
: Directional antenna (yagi's), doppler, and TDOA (Time Delay on
: Arrival) are the core RDF approaches, all have significant
drawbacks
: for this application, but TDOA has worked out to be the most
practical
: for me. Using the "body-block" a lot of times you can resolve
the
: direction 0/180 without the triangulation dance, if you have a
signal
: strength reading, which is also good for distinguishing
reflections
: from the real source signal.

 

[SioL]

There a kiddie GPS locators for under $50- price is dropping everday-
these are wristwatch assemblies- adapt one of these.

Yeah, 20-50US$/month for their service. The device itself is 199US$.

Hardly cheap.

SioL

 

[Fred Bloggs]

Yeah, 20-50US$/month for their service. The device itself is 199US$.

Hardly cheap.

SioL

Not quite- it is a set of two Mickey Mouse watches and a base station-
the watches are short range communication with base station and have GPS
receivers built in. There is no service to buy.

 

[Fred Bloggs]

Could you by any chance post a link to a gps unit in that price range?

I have look at a LOT of gps tracker devices and have never seen
anything in that price range except when it required a monthly service
fee, that ranged from $29.95 - 59.95 a month, and some even had a per
find additional charge. I don't doubt you, I just say this so you
don't think I am too lazy to look it up myself, I have looked and
looked and looked...

The other thing, at least of the ones I can find, is that they are
pretty big, even accounting for the case and hardened parts, they did
not look like you could break it down small enough for a cat.

The other issue with the GPS units is you typically need two things to
work, one, the device has to "see" the sky to get the GPS fix, and it
has to "see" a cell network to communicate the location information.
There is one that just uses the cell system to get it's fix, at least
that takes out one logistical issue but they only operate out of a few
major cities and nearby surrounding area's.

For people wanting to be found and cars this is not as big a problem,
however, for a cat it might be, I still think GPS a very attractive
approach, you could eliminate the need for the cell and a service
company by transmitting the fix from the collar, just the range would
be limited to 1/8-1/4 mile at best.

Woz (of Apple fame) is sinking some major dollars in to an inexpensive
"object" tracking system where one of the goals is that the part that
gets tracked, in this case the part the cat would wear, is about the
size of a typical army dog tag, and these tags apparently will also
operate peer-to-peer and peer-to-host, allowing them to form extended
networks where the object is not in cell range but in the peer-to-peer
network range.

He is thinking of everything from wallets, even credit cards, pets,
people, cars, bikes, you name it. However, there is no time line I
have found and it may be years out, I can't seem to find anything but
a mention here and there about it.

Anyway, if you have any links to small GPS devices, for any purpose,
kids or not in that price range I would greatly appreciate it is you
would post one or more.

Thanks.

I see this world-wide Wherify thing is cluttering up the search results.
There are much cheaper "out-of-range" systems that alert the parent when
the child device exceeds a selectable range- among these are some that
also give a GPS location- strictly short range. If you can't find one
then just make one- Motorola has some mass-produced single chip solution .

 

[Bob Thomas]

: On Thu, 17 Jun 2004 23:38:33 +1000, John Tserkezis
:
: >Dizzee wrote:
: >> Does anyone have a circuit diag. for a small tracking device.
: >> or point me in the direction of some publication or web
sites.
: >> I would like to make a short range (100-200m) for... and I
know it's a bit
: >> sad... my cat.
: > Something like a crystal oscillator with buffer (just supply
5v). Looks like
: >a smallish rectangular can with four pins (only three used, 5v
in, gnd, and TTL
: >output).
: > Output goes to a loose wire.
: > Use a scanner tuned to listen to the carrier, and a
directional antenna will
: >help with the direction.
: > A dipole will have two "blind" spots, a bit of triangulation
will tell you
: >which of the two blind spots is the real direction.
:
: RDF (Radio Direction Finding or "Fox Hunting") is the right
approach,
: however, in what you describe the battery life for a battery a
cat can
: carry would be under a day, believe I know from first hand
experience
: , that is, transmitting at the legal max power for
non-licensed
: public frequencies.

Actually a small pulse at 400 to 500 mS intervals is enough to
track. A 100 mW signal will handle the range, and with a 50 mS
pulse the average power is less than 10mW. Most small batteries
like a AAA will last quite a while at that poser level. Maybe
even several days.

Three AAA cells should do it, and at 560mA and a load of 15mW
total, the batter8ies will last at least 48 hours. Maybe a little
more.
The frequency should be picked with an eye toward low
interference and easy access to a receiver. If you use a small
short-wave receiver 10 meters is pretty quiet now. (sun spot cycle
near low) so it would be pretty useful and an antenna can be
pretty short, just wire in the harness the cat wears. Tuning the
antenna with a bit of inductance will improve the range, you'll
have to experiment.

Good luck, sounds like a fun project!

With the right equipment you can track on pulses, but it is very very
difficult with the typical RDF stuff out there, especially in a
neighborhood setting with a lot of reflections. It is easy to have
multiple sources with nearly equal signal strength.

You are right about the battery life, but to change batts every few
days would be expensive, a pain in the butt, and if your pet took
longer to find you would be out of luck. (AAA is also weird on form
factor for the collar.)

The antenna can be dealt with as you described, in fact it's your only
real option, but even with a professionally designed coil antenna from
Linx Technologies, it only had 2/3 rd's the range of a 1/4 wave whip
antenna and even less if the whip was mounted on a nice ground plane.

The collar I came up with gets about 90 days batt life under typical
use conditions, and can be as short as 35 days on a pair of 5800mAh 3V
coin style batts. Batts any bigger are not practical on the cat. I buy
the coin batts in bulk for under 2 bucks each, so the annual cost
operational cost is about 12 bucks. The parts that make up the collar
are under 100 bucks.

I have had mine going for over a year now, it was a fun project (for
me necessary also) and there are a lot of challenges in addition to
the electronics which is really pretty easy, for an electronics type.
Getting an end-to-end system and process that is effective, is another
story.

No matter how you approach the collar/transmitter, RDF, or "fox
hunting", the tracking job, is a blend of art and method, it takes
practice and it helps if you have a "touch" for it.

 

[Bob Thomas]

I see this world-wide Wherify thing is cluttering up the search results.
There are much cheaper "out-of-range" systems that alert the parent when
the child device exceeds a selectable range- among these are some that
also give a GPS location- strictly short range. If you can't find one
then just make one- Motorola has some mass-produced single chip solution .

Yes, The ChildMinder is the hottest one of those out there, cheap
also, but it is not effective for this application for a number of
reasons. The kind that transmit GPS co-ord's would be fine, but they
run in the 500 buck range, not 50 buck, and have a monthly service
fee, and again, there would be serious size and form factor issues to
deal with.

Thanks anyway for the reference, I looked at those also in the initial
search for a suitable off the shelf device, this was a tough nut to
crack. I went in to it thinking I would just go on the net search on
pet trackers, buy one and be done with it. ha!

 

[Bob Thomas]

Not quite- it is a set of two Mickey Mouse watches and a base station-
the watches are short range communication with base station and have GPS
receivers built in. There is no service to buy.

Again, not really right for this application, the cat will be out of
range of the base station a lot of the time, these systems are
designed for distances of feet, and short times, not 24x7, with the
range of a wondering cat. I wish the answer was that simple.

 

[Roger Gt]

: >: >Dizzee wrote:
: >: >> Does anyone have a circuit diag. for a small tracking
device.
: >: >> or point me in the direction of some publication or web
sites.
: >: >> I would like to make a short range (100-200m) for... and I
: >know it's a bit sad... my cat.

: >Actually a small pulse at 400 to 500 mS intervals is enough to
: >track. A 100 mW signal will handle the range, and with a 50 mS
: >pulse the average power is less than 10mW. Most small
batteries
: >like a AAA will last quite a while at that poser level. Maybe
: >even several days.
: >
: >Three AAA cells should do it, and at 560mA and a load of 15mW
: >total, the batter8ies will last at least 48 hours. Maybe a
little
: >more.
: > The frequency should be picked with an eye toward low
: >interference and easy access to a receiver. If you use a small
: >short-wave receiver 10 meters is pretty quiet now. (sun spot
cycle
: >near low) so it would be pretty useful and an antenna can be
: >pretty short, just wire in the harness the cat wears. Tuning
the
: >antenna with a bit of inductance will improve the range, you'll
: >have to experiment.
: >
: >Good luck, sounds like a fun project!
:
: With the right equipment you can track on pulses, but it is very
very
: difficult with the typical RDF stuff out there, especially in a
: neighborhood setting with a lot of reflections. It is easy to
have
: multiple sources with nearly equal signal strength.

Huh? Pulses are easier to identify from the background noise.
Metal sheds make interesting reflectors, but move a few yards and
the reflection is gone.


: You are right about the battery life, but to change batts every
few
: days would be expensive, a pain in the butt, and if your pet
took
: longer to find you would be out of luck. (AAA is also weird on
form
: factor for the collar.)
:
: The antenna can be dealt with as you described, in fact it's
your only
: real option, but even with a professionally designed coil
antenna from
: Linx Technologies, it only had 2/3 rd's the range of a 1/4 wave
whip
: antenna and even less if the whip was mounted on a nice ground
plane.

Let's see, 2/3 of 600 Yards? Yep, 400 Yards! It will do!

: The collar I came up with gets about 90 days batt life under
typical
: use conditions, and can be as short as 35 days on a pair of
5800mAh 3V
: coin style batts. Batts any bigger are not practical on the cat.
I buy
: the coin batts in bulk for under 2 bucks each, so the annual
cost
: operational cost is about 12 bucks. The parts that make up the
collar
: are under 100 bucks.

So your selling these?

: I have had mine going for over a year now, it was a fun project
(for
: me necessary also) and there are a lot of challenges in addition
to
: the electronics which is really pretty easy, for an electronics
type.
: Getting an end-to-end system and process that is effective, is
another
: story.

: No matter how you approach the collar/transmitter, RDF, or "fox
: hunting", the tracking job, is a blend of art and method, it
takes
: practice and it helps if you have a "touch" for it.

Like walking and chewing gum? Or pedaling a bike and breathing?
Oh yea!

Maybe I missed something here. The cat will come to eat at regular
intervals, swap the batteries every other day!

I have a Fox Hunt transmitter on 6M which outputs a 200mS pulse
every ten seconds. Never had problem tracking it! It used to be
set for 1S every 20S, but it is easier to get a fix with more
repetitions closer together. The power is 1 Watt, so that circuit
would not apply to this application. Range 4-6 miles.

200M range does not require much power nor a perfect antenna.
Maybe a cell phone for the cat would be the way to go?

My cat does not go out unless I'm with him. We have coyotes who
hunt here at night, they even kill German shipyards to feed their
young. My Daughter had three of her cats picked off despite her
efforts to keep them in a safe environment (our yard) with a six
foot masonry fence and electronic alarms.

5800mA coin cells? I used AAA cells because they're small cheap
and rechargeable. The entire rig fits in a plastic pill box (water
proof) and it is small enough to attach easily to the harness My
cat wears when we go for a walk, a standard harness I bought at
"PetSmart" Even at .75M a whip would be a "cat toy" sticking up.
So I figured a insulated wire in the fabric of the harness was
most practical. By making the unit a transponder it would have a
longer battery life too. But you need a receiver in the remote to
trigger the transmitter. A garage door remote recover would not
have enough range, so it is a new design.

Cost, the remote components should be about $20 total. The
receiver is what ever you can find that will work on the frequency
you select. A receiving loop on Ten works really well and it's
small.