| ash's Cheap-O Astrocam IV Page |
| A Peltier-Cooled Vesta/SC2 With Integrated CCD Chamber / Cold Finger |
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This camera started life as ordinary Philips VestaPro 680K webcam. With a few
dollars worth of junk-box parts, a Peltier-device, some hunks of aluminum, and some
valuable information from Steve Chambers (the inventor of the famed "SC"
modifications), this humble web camera has turned into a cooled, long exposure,
single-shot color camera! You can (and should!) read the official
instructions of the electronics portion of this modification at Steve Chambers'
website [THANKS STEVE!], and also see some images made with similar cameras on the
QCUIAG web site.
| NOTICE - THE ELECTRONIC PORTION OF THE WEBCAM MODIFICATION DESCRIBED ON THIS PAGE IS DERIVED FROM THE INTELLECTUAL PROPERTY OF STEVE CHAMBERS. IN RETURN FOR HIS GENEROSITY IN FREELY SHARING THE DETAILS OF THIS MODIFICATION WITH US, HE REQUESTS THAT THIS INFORMATION IS NOT TO BE USED FOR PERSONAL GAIN OR COMMERCIAL PURPOSES (WITHOUT PRIOR ARRANGEMENT WITH STEVE CHAMBERS). THIS MEANS THAT WEBCAMS MODIFIED ACCORDING TO THESE INSTRUCTIONS MUST BE FOR PERSONAL, NON-COMMERCIAL USE ONLY, AND MUST NOT BE SOLD TO OTHERS FOR PROFIT! STEVE'S COPYRIGHT NOTICE CAN BE FOUND ON HIS SITE - PLEASE READ IT! TO VIOLATE HIS REQUEST MAY BE ENOUGH TO KEEP HIM FROM FREELY SHARING OTHER FUTURE IDEAS AND INVENTIONS WITH US! |
On this page I describe a few details on how I transformed my VestaPro 680K.
You can try the same thing yourself - BUT BE WARNED - IT IS
POSSIBLE TO EASILY RUIN YOUR WEBCAM!!! And also, needless to say,
doing anything like this will most definitely void your camera warranty!
And finally, I will accept no blame or responsibility for any bad stuff you may
wind up doing!
Still reading? Good! Here is the circuit I used, which according to Steve might work for any CCD camera using the 16510 chip (such as the Philips Vesta, ToUCamPro, and the Intel Create & Share Camera Pack). This is Steve's "Advanced Modification", which incorporates several modular sections: separately controlled even-odd field read-out, separately controlled exposure time, and separately controlled "CCD-chip amp off" feature (to reduce noise emanating from the CCD chip's onboard amplifier, which can be significant for exposures over 30 seconds or so).
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NOTE: I recently read on Steve's page about a slight alteration of this circuit for use with the ToUCamPro 740K: it might be advantageous to add a 470 Ohm resistor and 10uF capacitor across the transistor's C-E pins - see Steve's page for details. You might also want to see his page for his nifty PCB layout graphics!
For my specific project, the parts required for the electronics portion, in addition to a willing Vesta Pro 680K, are:
And here are the parts used for the custom, cooled enclosure:
The many small yet important details, such as how to disassemble the Vesta, where and how to lift the 16510 and CCD pins and make the solder connections, etc., are not covered here. These steps are similar to those detailed on my previous camera mod pages, as well as others' extremely well documented websites. A good place to start for these kinds of details is at Steve Chambers' website. In addition to his documentation, he maintains a list of website links to other pages detailing modifications to Vesta 680's and other "SC-capable" cameras. An extremely nice presentation is made on Robert White's website.
Instead of the electronics details, I present here some pictures of the camera enclosure I made, as well as the combined cold-finger / CCD chamber used.
The combined cold-finger / CCD chamber design I came up with is detailed on another page at this site. It was designed with machining in mind, but since I do not have the necessary equipment and could not find anyone to do it for a reasonable fee, a compromised but still useful version was produced. With the help of a fellow astro-imager (thanks Randy!), we were able to produce this:
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It is composed of several pieces of scrap aluminum with the slightest of machining. At the bottom, a 2x2" square of aluminum is used to mate with the Peltier device. Above that, a 1.5" cylinder of aluminum was sliced (by the scrap dealer :) to make the slotted and short hollowed cylinder blanks. In between and on top are 1.5" steel washers. Randy cut the slot which is used to cradle the CCD as well as milled-out the hollow in the cylinder piece. The whole rig is held together with 4 machine screws and nuts through holes drilled through the stack, and made "thermally tight" with the application of thermal paste between all mating surfaces. Note the counter-sunk screw heads under the base, and the slots cut with a Dremel tool into the washers to accommodate the screws (those washers are made of very un-drillable stuff!)
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The hollowed cylinder and two washers serve as the container for the two rubber bands and optical window, as seen in the "ideal" design:
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On to the box! It is a nice, thick, and substantial plastic "Bud" box, about $10. A rectangular hole is cut just a bit larger than the 30x30mm Peltier device, and four holes are drilled to correspond to the four holes existing on the corners of the heat-sink. Note the grooves cut into the lid to accommodate the Peltier wires (important for later):
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The heat sink is bolted to the box lid with some nuts, followed by the muffin fan (make sure the air-flow points toward the heatsink!) Additional nuts are used to raise the fan slightly above the somewhat fragile heat-sink "pins", and to tie the fan to the assembly.
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The Peltier device is then placed (with thermal paste) against the heat-sink face, and the combined cold-finger / CCD chamber is fixed on top of that (more thermal paste) with two machine screws and nuts. These two screws fit into two more holes drilled through the lid to correspond to two holes existing on the heat-sink. Because the Peltier device is a bit thicker than the box lid, the cold finger can be tightened down against the Peltier and heat-sink to make a nice firm grip. The two little grooves cut into the box lid come into play here, since the gap is not wide enough to allow the wires to pass between unscathed:
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That's pretty much it, except for the mounting of the wired CCD into the slot, and connecting the wires up. I hope that this page can inspire you or give some ideas for your own projects!