Toucam Pro II

Toucam Pro II Webcam: Mark I


Copyright Notice:
The electronic modification of the webcams is the intellectual property of the inventor, Steve Chambers. It is illegal to use this information for profit. Should you receive any money as a result of performing this modification or selling a modified camera, Steve has requested you send the money (less parts) to www.msf.org.


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

The Toucam webcam is a great webcam for planetary and lunar imaging, due to its high frame rate allowing you to gather thousands of frames in a short amount of time to stack. But there is a modification that can be made to expand its use to that of capturing faint deep sky objects.
In 2001, Steve Chambers discovered a way to electronically modify several different type of webcams to enable a computer to control the shutter, and therefore allow them to take long exposures. The name for this mod, SC1, is named after him.
In fact the main reason I bought the Toucam was to do the SC1 mod as I didn't have a way to electronically photograph DSOs, and didn't want to splash out on a D-SLR at the time. It was bought off of eBay for £40, far cheaper than dedicated astronomy cameras.


The camera before modification, with the frontplate removed and a telescope adaptor replacing the lens.

The Electronics

I did not use Steve's original modification design, but Philip Davis's adaption of it. His method involves cutting the PCB track rather than lifting up the legs of the 4 chip pins used in the modification. The instructions for his variation can be found on his site here. This is his circuit diagram:

PCB Layout

The parts of the PCB used in this mod are labeled below (except the CCD, which isn't touched for the SC1 mod). The LED and microphone can simply be removed as they serve no purpose when attached to a telescope. Two pins each from the PD16510 and the SAA8116 chips are used. Connections must also be made to the +5V and 0V of the USB connector.


The following pins on each chip are used (hover over the pictures for chip pinouts):
SAA8116
Pin 97 - Shutter Control Reset Output
Pin 93 - Vertical CCD Load Pulse Output
PD16510
Pin 10 - VOD Shutter Drive Pulse Input
Pin 8 - PG1 Three Level Driver Input

The webcam awaits its fate...

The Track Cuts

After removing the LED and microphone, the next step should be to cut the two tracks. They connect the two chips used in the mod, and the easiest place to cut them are just below the PD16510 as indicated. A sharp scalpel or similar blade is needed, as well as some sort of eye magnification. It is a good idea to cut the track in two places to ensure a good cut, but don't cut too deep - as the PCB is multilayered.

Having done this, check for lack of continuitybetween:
SAA8116 Pin 97 - PD16510 Pin 10 and
SAA8116 Pin 93 - PD16510 Pin 8

Soldering on the Wires

The pins you need to solder wires on to are 0.2mm wide, and 0.5mm apart. You will need thin wires, and very thin-tipped soldering iron - I used a 0.5mm tip, essentially a point. You'll also need patience and a steady hand. It is a good idea to hold the PCB securely in something, and have some eye magnification held up so you can use both hands for soldering.
I practiced on some old junk circuit boards, a good idea if like me, you've never soldered on such a small scale before.
Don't rush, take your time - and have some solder wick handy just in case.


Here are some pictures of the finished circuitry with the shutter control circuit made from stripboard. This was glued by the chip onto the place where the microphone used to be. The wires connected to the two chips were glued down to prevent them being knocked and coming off. (The piece of copper was a makeshift heatsink for the CCD).


The other side shows the switch used to flip between long and normal exposure operation. I've also added a small heatsink to the SAA8116 chip as it runs quite hot, adding to the thermal noise on the CCD.

The End Result

Although it all fitted nicely back into the original housing - I mutilated it in several ways. Large holes were made in each side to (hopefully) allow the cold night air to flow through and cool it all down. The bump on the underside is where I had a 3.5mm socket to connect the parallel port to. This was later replaced with the phono jack as seen in the bottom picture, due to interference problems.
To see some results, head over to the Deep Sky Object page


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