Toucam Pro II

Toucam Pro II Webcam: Mark II


Warning
0pening up your camera will void its warranty. There is a strong likelihood that you will destroy your camera if you do not perform the modifications correctly. Do not attempt this if you have no experience with electronics, or do no want to risk breaking your camera. By continuing reading, you accept these risks as your own responsibility.

Introduction

Although the overall results of the SC1 long-exposure mod were very pleasing, with it comes an increase in noise because of the longer exposures.This is thermal-noise and is caused by the CCD producing electrons caused by heat rather than the photons from what you're photographing. The heat comes from the CCD itself as it operates, but also from the large SAA8116 chip mounted directly behind the CCD.

For the modification I will remove the CCD from the webcam board and mount it on a cold-finger, cooled using a Peltier device. It will then be away from the heat of the SAA8116 chip, and will be actively cooled below ambient temperature by the Peltier device. It also gives me a chance to rehouse the whole camera, which at the moment looks rather mutilated.

Removal of the CCD

The first step is to remove the CCD chip. I had to remove some of the glue securing the wires from the SC1 mod to get to the pins.
Using a scalpel or similar, carefully melt the solder on each pin with a fine-tipped soldering iron whilst lifting each leg up in turn.
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As my cold-finger was flat, I needed to bend the pins up so that they didn't come into contact with the metal when the CCD was laid down.
Do this very carefully if you need to, as excess bending or force will snap the legs... not good.

Wiring up the CCD

Next 14 wires must be attached to the CCD. It is much easier later if they are different colours, and if they are shielded it will help to cut down on interference and banding problems. I used some 9 core screened cable and took out two of the wires, using one length for each side of the CCD.
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Solder each wires onto the pins of the CCD.


...and repeat on the other side. It is a good idea to put some insulation between the pins of the CCD. I later threaded some paper between them and wrapped the ends up with some tape to secure it.
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Then you'll need to solder the 14 wires onto the webcam pcb, where the CCD used to be. Check, and double check that you are connecting them in the correct order. I later covered them all in glue to insulate them from each other and to secure the wires.
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The Peltier and cold-finger

My cold-finger is simply a piece of aluminium, which used to be a transistor heatsink. After applying a small amount of thermal paste to the underside of the CCD, I glued it all down to the cold-finger. The ring of silicone sealantis to form an airtight seal to try and stop condensation forming on the CCD and contacts. I drilled 3 holes through to easily attach it to the casing.
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A Peltier device is a thermoelectric device which transfers heat from one side to the other when a voltage is applied across the two wires. Because it will get hot on one side, a heatsink needs to be attached to prevent the Peltier from being damaged. The one I used is an 8.4V one I bought off of eBay. I fitted it with a heatsink from an old PC, and fitted a simple switch to the casing.
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The housing is made from a cut up small plastic box. I took the front side of the original webcam housing to glue on, so that I could easily fit the sensor into place, as well as the adaptor to attach it to the telescope. I also added the other half of the sealant ring.
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Final Result

This is the finished product (without the top part to protect the electronics). After all the little camera had been through, it still works. As for the noise, it is noticeablyreduced even without the Peltier turned on, just due to the CCD not being near the hot chip and the cold-finger acting as a heatsink. However, when applying 5V to the Peltier, the noise is reduced even further even on maximum gain.
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