Author Topic: Teardown of an ISG Talisman Thermal Camera by Mike  (Read 16994 times)

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Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #25 on: December 30, 2017, 05:25:00 am »
Power and Backplane PCB's......
 

Offline Alexander R

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #26 on: December 30, 2017, 05:28:25 am »
Ooookay; Well, all that stuff seems to need a lot of space. So my plans to fit all that is really needed get harder realize.
The motor itself should not be a problem. As long as I can unscrew everything more or less easy I can replace that one for sure.
I was wondering if the main board was smaller... But looking at the pictures, I am in doubt that all the new housing can get small enough for me. And it's called main board for a reason, I bet. So I cannot "just" leave it out, hm...? ;-)
I was outside a while ago. Took the Dräger that is ok and was stunned of the still very good quality of it. Could recognice and identify my dog Elvis from, well, very far away (About 40cm shoulder hight he has).
 

Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #27 on: December 30, 2017, 05:46:42 am »
The Raytheon kit produces a perfectly usable camera on its own. The kit comprises the following parts that you can extract from the Talisman.

From the front.....

1. Lens block
2. Chopper wheel and motor
3. BST sensor PCB
4. Backplane PCB
5. Raytheon Core PCB
6. Power supply PCB (not required to be the one from the Talisman but that would be the simplest way)

The output from the Raytheon Control PCB is composite video.

Miniaturisation of the BST core is most limited by the large sensor array and its Chopper wheel.
Building a camera using the Raytheon Core kit does require a decent knowledge of electronics.

Fraser
 

Offline Alexander R

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #28 on: December 30, 2017, 06:36:35 am »
That sounds to me as if I have to keep the whole stack, maybe just can fit it in a little smaller housing, but that's it.
If there was a small pcb that would connect to the sensor array and that would have a video out... That would be nice. But I think in that case I could try to get a used FLIR Tau or Vue instead. Ok, still very costly.
 

Offline Spirit532

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #29 on: December 30, 2017, 06:57:18 am »
For professional firefighting cameras, they still look like a horrible hobbyist bodge all around.
 

Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #30 on: December 30, 2017, 07:55:26 am »
Spirit532,

There is a lot of interesting history behind ISG and it's camera designs. The man behind ISG was Ex EEV ARGUS. Basically It appears he took his EEV ARGUS TIC knowledge and started a new company.

The Talisman is basically a 'cottage industry' thermal camera that is built around the Raytheon BST Core kit that the ARGUS 2 used. It should be stated at this point that the EEV ARGUS products are a far more professional piece of hardware that incorporates sound engineering and excellent electronic design.

When I first saw inside a Talisman I thought it was a dodgy DIY build. There was a very basic bent aluminium plate chassis and masses of RTV spread around the unit. The whole unit looked home made and very amateur when compared to the ARGUS 2 that I know so well. The RTV was intended to stop parts and connectors moving if handled roughly.

The Talisman case is also a very crude affair and could never be described as good looking or of impressive design. I personally dislike the Talisman cameras but have a few for projects that may, or may not happen  ;D

In the world of bespoke, limited production run equipment, it is not that unusual to see the build style and questionable build quality found in the Talisman. Some such units are iterally built in a shed with basic tooling and limited budget. Such equipment often looks very home made, but it performs the desired task. A 'It ain't pretty but it works' kind of situation. The Talisman prototype might be excused such build style and quality, but this was a professional fire fighting tool. It should have been better.

The good news is that the chopper wheel is relatively resilient and the Raytheon Core kit is easily extracted in order to use it in a different format case. Take a look at the EEV ARGUS 3 for an alternative camera format that uses the same style of Raytheon BST core kit. It is EEV's attempt at moving from the 'gun' or camcorder style ergonomics to the upright camera format that is now common in mobile phones. The E2V Mi-Tic (microbolometer sensor) that I own continues with this format and I must say I love the Mi-Tic  :)

Fraser
« Last Edit: December 30, 2017, 08:00:33 am by Fraser »
 

Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #31 on: January 03, 2018, 12:16:56 am »
The ISG story is a little different to that Fraser has given, the split happened a lot earlier back in the EEV-P4428 / Pevicon era and both companies essentially developed in parallel when cores became available from Raytheon. Quite a few EEV folks headed down the road.  ISG had a slightly greater interest in solid state cores as they did not make Pevicon tubes - EEV did and had the financial benefit (and technical drag) of their own sensor supply.
Rumour has it that the Talisman case was originally moulded on a Morris Minor inner wing.

I am not sure quite how easily the Raytheon core can be extracted from the Talisman electronics set, but it should be no worse than from the Argus 2 or 3 cameras.  Much depends on exactly how much is intercepted by the ISG backplane and control PCB.
There were only two PCB in the Raytheon kit, a detector PCB and a processing 'SECCA' PCB, and both EEV and ISG made their own detector PCB containing the Raytheon circuit to get control of the shape.

The 'Backplane' PCB Fraser shows is an ISG design to connect to the SECCA. With the Raytheon detector board (and also the EEV Argus 2 version) the SECCA 80 way connector fitted directly to it.  ISG have inserted a cabled connection to the sensor and included iris and fan control.  I never worked out what the fan was for - it only made things worse.

I have plenty of the chopper wheel motors if required by anyone, either variety.  Just drop me a mail.



regards
Bill




Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #32 on: January 03, 2018, 11:39:41 am »
Here is an image of the minimal Raytheon BST camera core built from an Argus 2, the lens and chopper wheel are omitted.

With suitable test connections this can be a 'Power-in Video out' system, and runs without the EEV/Marconi control board and display.  I am not sure if the ISG implementation would allow a similar extraction although the cabling would give some flexibility in mounting.

The same can be done with parts from an Argus 3, which by its' nature is a thinner form factor.

regards
Bill

 
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Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #33 on: January 03, 2018, 12:58:18 pm »
Thanks Bill  :-+

Excellent information, as always, from you  :)

I am thinking that the Mechanical IRIS found on these fire cameras may not be essential at more limited temperature ranges, so that would further simplify a system 'slimming' process. Of course the EEV and ISG camera control boards would likely complain about no IRIS detected, but without those boards the core looks like it would behave like the IRISless Thermal Eye 300A camera.

Fraser
« Last Edit: January 04, 2018, 01:43:52 am by Fraser »
 

Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #34 on: January 04, 2018, 01:00:24 am »
Hi Fraser,

The core shown above does not have any iris functionality, so you'd just ignore or remove the iris mechanics and go.  What it does have added is a couple of links / pots to take control of the image away from the Control PCB and give it back to the Raytheon core which is probably how the 300D and Cadillac cameras are set up to work anyway.  This could be set to allow some AGC functionality in the core in place of the iris although ultimately the Raytheon BST sensor had a relatively limited dynamic range.

I do not know how the ISG camera is set up to work, but if anyone fancies probing a couple of pins on the 80 way connector I can tell you.

As you note, an EEV/Marconi/e2v Control PCB would put up the warning triangle on its' video output and therefore on the screen.  The core's own analogue output would not be affected.

regards
Bill

Offline Alexander R

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #35 on: January 08, 2018, 12:52:04 am »
Hello guys, some short info from the non-electronics side.
Just came back from holidays. Pulled everything out of the housing (which seems to be made relatively... simple; looks in the inside like my first attempts of making GRP parts for model airplanes when I was 12 or so...).
Once the whole stack was without the housing, it worked just fine. No flickering of the image visible. I can not test the Video out as I have vo BNC-cinch converter here. But I will do.
There was a lot of silicone on the threads of the front caps of the two lenses (making them "water tight"...?). I removed most of it, put everything together again and it works just great.
The other camera was almost the same, but the motor for the shutter wheel seems to be weak. Most of the time it is working good. Holding the camera face down or up an then shaking a little bit (axial direction) lets the image flicker, then stabilizing again. So either the bearing of the motor are the reason or something else. But it's mechanical.

Bill, what information would you need to look for aproper motor and: Would you sell me one?

Or I might be thinking getting rid of two of those cameras, if someone would be interested. I still have one, looking for another one and just lost my job (extra tip: don't become a pilot in Germany...). So clearing up would be a good idea, too. :-)
 

Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #36 on: January 08, 2018, 01:22:08 am »
Alexander R,

Sorry to hear about your job loss  :(

The motor used for the chopper wheel is a relatively low torque coreless design that does suffer issues when the camera is panned quickly. The more powerful CD drive motor overcame this issue. The motor would not normally become 'weak' but the bearings can become an issue if they become tight. It would be worth comparing the voltage across the motor on the two cameras and the current passing through them. There could be a motor driver issue effecting the motor that appears 'weak'

I have provided pictures of the motor so Bill will recognise it as the same that is used in the ARGUS 2 cameras that he kindly supports.

Sadly I cannot offer a home to your cameras as I already own five of them  :palm: I will likely sell mine at some point in the future as well. They are a very affordable basis for a DIY thermal camera project and do perform well when correctly set up.The sad truth is people seem to be put off by the relatively ugly casing on these cameras. The Raytheon Core that resides within is very nice quality though. The lens block alone cost a great deal of money when these were built as they are high quality Germanium lens elements of decent size. Some people on ebay recognise this fact and strip out the lens elements to sell separately for more than they can achieve on the whole camera ! Its a weird world we live in.

Fraser
 

Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #37 on: January 09, 2018, 11:59:35 am »
Hi Alexander,

No problem sorting you out a motor. Drop a PM/email.

There's a lot of silicone in those early ISG products and it was a bit 'DIY' back then for them.  Rumour has it that the Talisman GRP case was moulded on a Morris Minor inner wing.  It is in fact a fairly well accepted technique for fire helmets. 

Using it for a camera case - and those glued on bushes inside - is not so clever.  They did not survive drops very well.

regards
Bill

Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #38 on: January 12, 2018, 12:09:05 pm »
A couple of pictures of the Raytheon core 'minimal camera' from an Argus 3.

The partly cut off connector allows power-in video-out.
Some minor fiddling is needed to bypass the Argus 3 control drive via the MAX510 - for a later thread of its' own.

Bill

Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #39 on: January 12, 2018, 11:37:40 pm »
Thanks Bill,

The first pictures of the ARGUS 3 internal chassis I have seen on the WWW.  :-+

It is a nice chassis suitable for incorporation into DIY projects  :)

Fraser
 

Offline Bill W

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #40 on: January 13, 2018, 11:25:08 am »
You mean you have not done a teardown on any of yours yet........... tut tut  :) :) :) :)

regards
Bill

Online Fraser

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Re: Teardown of an ISG Talisman Thermal Camera by Mike
« Reply #41 on: January 13, 2018, 02:08:49 pm »
 :-DD

I know Bill, I am ashamed of myself  :-[

I have too many partially completed camera projects so did not want to open anything else up until I have the situation under better control  :) I was hoping to find a better condition Argus 3 case into which to transfer the electronics package, and would then have combined the opening of my working ARGUS 3 with the transplant operation. Otherwise, I end up with boxes of disassembled cameras awaiting action  ;) I have decided that I would like to restore my Argus 3 as the slimmer model that does not have the side handles. Sadly I missed out on the last sensibly priced good cosmetic condition faulty Argus 3 on ebay and I am no longer looking for thermal cameras, as per my New Years Resolution  :)

I shall have to get onto that restoration soon, but I am about to start my major sale of other equipment via ebay so I must get that sorted first.

Fraser
 


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