Bruno28,
Congratulations on buying an EEV ARGUS 2
There is a lot of information about the EEV (E2V) fire fighting cameras here :
http://www.fire-tics.co.uk/1. The ARGUS 2 was released sometime around the year 2000. I do not know it's exact release date but the datasheet was dated 2000.
2. A Raytheon 320 x 240 pixel BST temperature stabilised imaging sensor is used in the ARGUS 2. BST technology requires a rotating chopper wheel to create the required changes at the face of the sensor. The chopper wheel was often quite a large diameter of around 3" but EEV did manage to reduce the diameter in some specialist cameras of that era. The chopper wheel tends to dictate the width and height of the cameras front housing.
3. Many Raytheon BST based cameras of the period were quite large due to the available technology, and required ergonomics of the application for which they were designed. The Raytheon Thermal Eye Palm 250D was quite compact and in camcorder format, but still a large camera by modern standards.
4. Raytheon used to provide OEM's with a thermal camera 'kit' that included the BST sensor, chopper wheel and the image processing PCB. The dimensions of the lens, BST sensor, chopper wheel, chopper wheel motor and processing PCB dictated the minimum size of the camera. The Raytheon 300 series modules is about as compact as was possible for a BST based camera of the time that used the standard Raytheon kit of parts.
Some thermal camera OEM's of the period just bolted a Raytheon 300 camera module into a housing and added a display plus minor housekeeping electronics. That was the beauty of those Raytheon Modules..... you provided power and they output thermal images
Fully automatic except for focus.
5. You may have heard of the Cadillac De-Ville car Night Vision system that used a Thermal camera ? If not, I did a tear down of one on this forum. The camera is basically a Raytheon 300 module in a weather proof housing. Perfect for the automobile industry but very expensive at the time. I own two of the Cadillac cameras and, for the era in which they were used (Circa 2001), they were both advanced and capable technology.
6. So why did EEV design the ARGUS 1 and 2 to be relatively large compared to the Raytheon 300 module ? You need to look at other fire fighting cameras of the period as well. The likes of the SCOTT, ISI and ISG offerings.... they were all large with simple controls and a hand holds, and for good reason.
Fire fighting cameras are a very special thermal imaging tool. They require the following features :
a) Easy to hold with a heavily gloved hand
b) Ease of use. Preferably power on button only and fully automatic after that
c) Produce a decent quality thermal image in changing ambient and thermal scene temperatures. Remember these camera have to cope with horrific ambient temperatures and to image burning material at up to around 1000C
d) Survive being dropped - a common hazard in fire fighting.
e) Survive being dowsed in water and potentially submerged ! Goes with the territory !
f) Have an easily fitted battery pack of reasonable operational duration.
g) Be fire resistant !
h) Have a display that is easily used by a fire fighter in varying conditions of visibility (smoke filled room) whilst a air supply and mask (BA set) is in use.
To meet these requirements EEV used the following :
a) Large easy to grip handle with large easy to press power button for the thumb. Side straps to aid hand holding.
b) Raytheon BST based core fitted with an F1.0 fixed focus Germanium lens, mechanical IRIS for high temperature capability and custom EEV electronics for camera control, overlays and display etc.
c) Multi layer environmental protection comprising rubber block shock mounted chassis in a hermetically sealed inner camera module that is surrounded by a custom shaped thermal blanket, and then fully encased in a fire resistant outer hard sacrificial shell casing. The outer casing was designed to be field replaceable by the owner if it ever became damaged. The camera could withstand being dropped and even being briefly immersed in water. The thermal barriers incorporated in the design kept the electronics cool enough for correct operation in an enviroment that was even too hot for humans to work in.
d) The battery pack was located in the handle and had a quick load and unload mechanism. It resembles the magazine location in an automatic pistol and is relatively easy to change the battery even in total darkness. The OEM recommended fresh batteries on every entry into a situation so battery changes would normally be done at the fire appliance anyway.
e) The display uses a CRT that is bright and of good image quality. The image is magnified with a large lens to enable the fire fighter to place the screen directly in front of the BA set air mask, and view the image with both eyes, even in dense smoke scenarios.
So Fire Fighting cameras are not your 'average joe' when it comes to design and usage. It is little wonder that they were unusual shapes and sizes. They met the needs of people who wanted to be able to easily grab and use a tool to good effect without worrying about where to hold it or where the buttons are located. It is a specialist tool. The technology of the period also influenced the designs but I know the ARGUS 2 could have been miniaturised by EEV had there been the desire to do so. It followed on from the very successful ARGUS 1 that used a far bulkier electronics package and the customer liked the form factor. Why fix that which isn't broken ? The design certainly worked for EEV and its customers as sales were excellent.
I own examples of the latest ARGUS cameras, namely the ARGUS 4 HR320 and Mi-Tic 320. These cameras still have to meet the requirements I detailed above but they are far smaller due to advances in technology and the desire by the modern fire fighter for a more compact, yet still very capable, personal thermal imaging camera. The ARGUS 4 and Mi-Tic are still very different to your average thermal camera though. Much thought has gone into their design as lives can be at stake if they fail to deliver.
Why did I have 21 ARGUS 2 cameras ? I agreed to repair them for an eBay seller that I bought an ARGUS 2 from. The result .... a set of fully operational and carefully reconditioned ARGUS 2 cameras that worked as well as the day they left the factory. The seller is saving these reconditioned cameras as his best stock as they performed so well. Each had a repair and test report supplied with it. If you bought your ARGUS 2 for just under £400 on eBay UK you likely bought it from that seller but your camera may not be one of the units I reconditioned for him. I have a record of the serial numbers I worked on though.
I gained a deep insight into the areas that need attention in these cameras after years of faithful service. They generally stand up to abuse very well. The areas that can need attention are:
a) The Germanium objective lens can suffer corrosion due to prolonged exposure to water over the years. Do not try to polish the lens ! You will remove the AR coating.
b) The power button contacts can become intermittent after many thousands of operations. The switch is not easy to disassemble so use of the spare contact pair is recommended.
c) The mechanical IRIS can become 'sticky' due to actuator lubrication contamination of the two leaves. This causes a fault icon on the cameras display and loss of correct IRIS position for a specific thermal scene. Careful disassembly and cleaning of the IRIS assembly is the only solution. It is easy to test for an IRIS issue. An alert will either occur at power on, or during a test where the camera is aimed at a cool scene and then a very hot scene, such as a flame, very hot soldering iron, an oven or heating ring on a stove. If you hear the IRIS actuator driving the IRIS leaves all us well. If you get an IRIS fault alarm on the screen, the IRIS assembly and actuator needs a thorough clean.
d) Degradation (splitting or shredding) of the translucent chopper wheel membrane due to age and temperature. This is not common but does require the replacement of the chopper wheel.
e) Rechargeable battery failure. age/use related. Note that the Rechargeable battery pack contains a special battery gauge PCB and not just a battery.
f) Battery door failure. Usually caused by abuse.
There are other faults that I met but I think that is enough from me for now.
Note that some spares may be available, if needed. See the Fire-Tics web site for details.
As already stated, the schematics for the ARGUS cameras are not public domain. There is help available via this forum and its members however.
If your camera has any 'issues' you will likely find help via this, or the Fire-Tics web site.
Fraser
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