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Audine CCD camera

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I have built my Audine CCD camera with the help from the French company Mécastronic lead by Matthieu Sénégas. It could not have been possible without the great work performed by some members of the Aude association. The CCD camera Audine is extensively described here.

The CCD sensor is a Kodak KAF-0402 ME. Its characteristics are

CCD type	Full frame Front-side illuminated with transparent gate Two phase transfer Micro-lens technology
Number of pixels	512 x 768 (3:2 aspect ratio)
Size	4.6 x 6.9 mm
Pixel size	9 microns
Filling ratio	100%
Quantum efficiency	77% peak, 44% @400nm
Capacity	100 000 electrons

The electronic interface has the following characteristics

Digitization	15 bits (from 0 to 32767)
Gain	4.35 electrons / ADU
Read-out noise	~24 electrons rms
Offset	2700 ADU
Computer interface	Printer port (LPT1)
Frame read-out time	13 seconds (it would be possible to improve with an Ethernaude)

A few more details for the ones who already know the Audine project ...

Shutter	Pentax 18mm
Cooling	1 Peltier stage, no temperature stabilization
Cooling option	Drain (in aluminium) is not insulated
Power supply	Computer power supply 5V/12V for Peltier element + temperature sensor LM311+ fan + shutter +/-15V stabilized power supply for all CCD circuits
Sealing of mechanical housing	Tape + acrylic mastic
Solution against water vapor and freezing	foam / sponge parts to absorb humidity + remove air volume

Humidity / freezing

I must mention that the main weakness of the Audine camera is humidity and freezing. It is to the point that many persons started to design upgraded sealed mechanical housings (which I guess should to be more expensive). The solution I adopted is working fine, I never had any problem though I opened the housing a number of times to remove some dust (I am a maniac and the flat images do not show any dust at this moment!).

My approach is twofold:
(1) sealing the housing with tape (brown) and acrylic mastic (white). The acrylic mastic is like silicone, it is very efficient for sealing. By contrast with silicon which is a nightmare to put and clean, it is really easy to manipulate so that you can put it in rather unaccessible places without any trouble and getting a clean result.
(2) a sponge cut in small parts to fill every possible remaining space inside the housing. I tried dessicants, I tried rice seeds (!) and sponge is the only working solution I found to absorb water. It's possible that decreasing the inside volume of air also plays a role.



On the pictures above, the two cables necessary for the CCD operation are visible. The flat one (ribbon cable) is connected to the parallel port of a Sony VAIO laptop. The other one is providing all voltages to the camera + sending back temperature sensor information ; note the fact that all individual cables are bunched (torsadé in French). The purpose is to reduce magnetic type radiation of current noise due to the unstabilized switched mode power supply used for 5V/12V. The bunched cables should reduce interference with the flat cable that reads CCD output. The same principle is used inside computers where 12V cables going to cooling fans are also bunched.