Audine Project

The audine CCD-camera is a very successful project for amateurs. Because of the excellent construction manual there are many audines worldwide. The original Audine Website is found here: Audine: Table of Contents.  Five enthusiastic members of our local astro club, Rainer Gröbel, Stefan Haas, Thomas Jäger, Jürgen Lamprecht und Norman Schmidt, have decided to build their own audines in summer 2001.
 


Camera #2 finished in july 2002


Features


Look at some features of our design:

1. we use the original printed boards from France
2. construction of a air-tight case
3. two-stage peltier cooler
4. single power supply with 12V
5. dc-motor as a shutter
6. temperature measurement and controlling
7. one cable to camera head


first try of our shutter

construction of a coldfinger

a wooden model to avoid collision of parts

adjusting the voltages before mouning the camera into the case


printed boards

We use the printed boards from Essentiel Electronique. The electrical components were bought from local distributors, except the AD-converter and the  temperature-ic. The CCD was directly supplied from Kodak (US). Three cameras have anti-blooming CCD-chips, in one camera is a KAF1600E. We use C2- or eng. grade chips, this is sufficient because of the cooling.


Lower Board
 


Upper Board. We did not place components on the right side, because we need
the space for our shutter board.
 


Upper board, here are the missing components


Power supply and temperature controller

Power supply and temperature control is done by a
self developed equipment. It is optimized for a 12V car-battery. Stefan Haas
developed a switching regulator which generates +15V, -15V, +5V from a single voltage.
A small microcontroller (c-control) reads the I2C-bus temperature sensors, controls the peltier current
and displays the functions and temperature on a LCD-display. Today we would choose an Atmel AVR Flash Microcontroller (programmed in C with AVR-GCC) for this purpose.

Controller
The controller opened
 

Schaltregler
The transformer is self made, the frequency of about 30kHz is generated by an simple NE555. A MOSFET amplifier acts as a driver. Linear Regulators of +18/-18Volts are located on the other side (left).
 

smd
There are two  LM76 SMD temperature sensors in the camera head. They have a small mass and their accuracy is 1,5°C between  -25°C bis +125°C. They transmit their information digitally via a I2C Bus.
 

Temperaturfuehler
LM76 mounted near ccd
 


LCD of the controller (background lumination adjustable)
Ts = temperature, Ti = current temperature, 11,5V = battery voltage, 64% cooling power
 

Setup
 

Connecting scheme, power supply
It is possible to use one single car battery for the whole system. Please make sure that the components do not interfere electronically. In practice, our Audine Controller didn't make any trouble in that case. Having the notebook at the same battery is sometimes critical. You can try version a), but most of the power converters (12V=/110-230V~) produce heavy interference on the 12V side. Version b) can work fine, but even if you choose a) or b), please check the whole system before. All components together can produce a heavy current (>4A). Therefore it is better to have a separate car battery, do not use the build in car battery.

Safety precautions: all circuits must have a appropriate fuses. A short circuit is very dangerous in that case.
If you don't have certain knowledge ask an expert.
 

Downloads (please read the note at the bottom):
controller schematic (gif,116kB)
schematic of round printed board (gif, 96kB)
controller layout (gif)
c-control basic software



Housing


We contructed our own aluminium case, which is black anodized


There are cooling fans on the back side.
A standard 80x80 computer fan will be mounted with four screws.


There are holes on the ground to attach the peltier elements and the printed boards.
On the right side there is an opening for the D-SUB connector.


The window of the cover is glued with silicon. In two cameras IR blocking filters replace the front glass.
On the left side is the drying cartridge.


Completed Audine camera. Between the body and the cover there is a O-ring sealing. On top of the cover is a M42 telescope adapter mounted.
 


Camera with 25-pol D-Sub connector and computer fan. Note: we have only one cable


Round adaption board


We had to integrate some electronic into the camera case.
The round printed board also adapts the original audine boards.


Note the aperture for the 30x30mm peltier element

Features of the adaption board


Voltage Regulators 18V -> 15V

In D-Sub-distance soldered pins

mounting for audine boards

SMD-temperature sensor #2 has thermical contact with the case

Download:
Layout adaption board


Cooling


Two-stage peltier cooler with elements supplied by a local distributor.
Peltron: PKE 36 A 0020 (4V, 3.8A, 8,5W)
Peltron: PKE 128 A 1027 (15V, 3.8A, 33W)
The elements are in series and have their maxium at 12Volts


Lower element (30x30mm)


The coldfinger with the upper element (15x30mm).
There is a thin film of Wacker SilGel 604 (two component silicon) between the surfaces.


Finished coldfinger. Ready for mounting the original audine boards

Temperature measurements  (+27°C ambient)
Warm-Fühler = case temperature
Kalt-Fühler = CCD-temperature


Shutter

We do not use the daco shutter. We decided to build a shutter board with a miniature dc-motor. A NE555 deals as a motor driver. An electrolyt condensator accelerates the motor.


 

Mounting of the shutter board

 

Closed shutter

Counterbalance with solder iron

Shutter opened

Note: use IR-blocking material for the shutter. Some plastics have a IR leak.


Drying

Drying cartridge

Cartridge filled with Zeolith. Our Calculations have failed, the complete filled
cartridge does not suffice. There is additional zeolith in a small bag inside the audine.


The cover plate in detail. Left, opening for the drying cartridge.
Right, a small nylon screw if we want to flush the camera with CO2, Argon or N2.


All electrical connections are realised with only one 25-pol D-SUB connector.

The opening with the green wires is hermatically sealed with silicon. The black and red wire is to connect the fan.


Please note: you need fundamental knowledge in electronics if you want to copy our design! We cannot provide any support nor a function guarantee!  It is all on your own risk!

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