Peltier Cooled Philips Toucam
I have acquired three webcams for astro use. The first one I bought (because it was cheap) was a Connectix QuickCam Express. This has not got much going for it; a low resolution and low sensitivity. Its OKish for lunar work but that's about it.
Next I heard about Steve Chambers work on modifying the Philips Vesta Pro for long exposures. PC World were selling these cameras off cheap so I bought one to experiment on. The idea being to modify a ToUcam Pro if this modification was successful.
The modification was a great success, so I then purchased the ToUcam Pro. This was swiftly modified, also successfully. I then set about providing some cooling for this camera, I wanted to preserve the camera as a webcam for video conferencing so remounting in a project box wasn't really on the cards.
[Click on the images below for a larger 640x480 version]
| Here's my initial test of the peltier chip, from an ambient temp of around 20C to -8C, running at about 2V & 1.25A. |
| Here's another view of the peltier mounted on the heatsink, and the 'cold finger' that I made to slip underneath the CCD chip. It's probably way too thin and small to be really effective, but it must do some cooling! |
| This is the view from above the CCD, it shows how the cold finger slips under the CCD chip which is raised above the circuit board. You can also see the wires from the Steve Chambers modification. Liberal use of hot glue has been made in attempting to secure the finger in position - more was added after these photographs were taken. |
| A side view, if you look very closely you can just make out the insulating tape stuck to the underside of the cold finger to prevent it shorting out on components on the circuit board. You can also see the thermal paste between the finger and CCD. If only I had this sort of magnified view when attempting the SC mod! You can see pin 9 of the CCD has been lifted in preparation for the amp off modification, but I had problems with this introducing noise to the images so I've reconnected it with a bit of wire for now. |
| A front view of the completed camera. |
| A side view of the completed camera. |
| The rear view. The switch enables/disables the SC mod so that the camera can still function just like an unmodified ToUcam. The socket is where the trigger cable connects between the laptop parallel port and the logic cct inside the camera. |
| I've been asked a few times if my cooling works. Well, I actually don't use it! So I performed a test. Here are two images taken at an ambient temperature of 20C, the gain on the camera was set to 75%, the expsoure time was 1 minute, and the camera put in mono mode.I think the conclusion is - YES it does appear to work. |