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Making a Homemade Webcam?
Space-Bot asks: "I remember back in high-school photography the simple and very basic homemade cameras that we made that surprisingly worked fairly well. Amazing how something so great started so basic. These days we have all these high tech gadgets that do it all so quickly you never really think about any of the work behind it. Well I would like to start to understand the modern digital cameras more and I figure what better way then to make a homemade webcam of some sort. Might some of you Slashdot guru's have some ideas or experience for my project?"
It'd be quite difficult to make a digital web cam. Sure, basic photography is simple. The reason? All you need to do is capture the light, and you've got a nice chemical compound that does that fine. You don't have to delve into the actual process of getting it to capture (yea you have to develop it, but the chemical compound on the film does the capturing).
With anything digital, you have to use a matrix of photo-sensitive sensors, process, and send them out to the computer. Which means you either need to buy a CMOS board, or that other kind of photographic digital thing. Figure out how it interfaces, connect a USB interfacing chip onto it (I think they're pretty cheap, Buffer->USB->Program, you handle the arrows and the Program, everything else you'd practically have to buy. I guess you could create the USB interfacing yourself, but that would be tedious, and not important. Using the serial or parallel ports would be easier if you're going to do it yourself, btw.)
Anyway, what another poster said. Go buy a cheap rebate webcam, take it apart, play with the parts some, and put it back together. I'm pretty sure there's nothing that's going to be hurt by light or by touching in a webcam (though not positive, IANADigiPhotgrapher).
This post is getting kinda long, but I wanna share this. I had this idea on a way to make a cheap, possibly portable, digital camera....well, not film camera at least. I'd take three photodiodes (diodes that block when there's light, and don't block when there's not), put the three primary color filters over them, have the light coming in through a slit, and hitting two mirrors, then going to the photodiodes. When you hit the button to take the photo, it rotates the first mirror horizontally, back and forth, as fast as possible, and the second mirror slowly scans down. The output from the photodiodes would directly going to a cassette tape. Later, I could read the cassette tape on my computer, and write a program to analyze it and extract the picture. I thought it was neat because the parts were cheap, but highly impractical. Especially considering it'd take about a second to take the picture with standard photodiodes (~25ns per reading, IIRC). Anything longer than 1/15th of a second *requires* a tripod...imagine the shaking going on with the motors as well.
Anyway, yea, happy learning and stuff.
A normal memory chip is actually light sensitive, in a nasty gray-scale sort of way. :) and write consistent values out (all ones or zeroes) then display what you read back in.
So, take an old memory chip, like a 1-meg or so. Carefully split the top off of it (might take a half-dozen tries to get one with pins still intact after).
The one I saw was plugged directly into a memory card. These days you'd probably have to rig up a parallel port interface.
Then all you do is put a lens over it for focus (watch out for the sun!
It's possible to achieve interesting things just by removing a webcam's built-in lens/filter assembly, and replacing them with lenses and filters from 35mm camera. See Lundycam for examples. You can build an extreme telephoto camera in this way for very little money.
You can also change the webcam's behaviour (improving low-light performance, for example) in software by using something like the Java Media Framework.
If your interest is purely academic, you might check out the CCD Camera Cookbook Webpage. The CCD Camera Cookbook is a book covering the design of two CCD cameras for Astrophotography. The resolution of these cameras is not high, and they do not come out being cheap. I am currently reading the book and will probably build the TC245 camera as a prelude to trying to design my own higher resolution CCD camera for Astrophotography. I think the book alone would be a good start in an attempt to understand CCDs.
I've used my Cellphone as a webcam as a proof of concept and it worked fine.
I was even able to walk across the room with bluetooth.
This site has quite a few links to people's NBTV projects and software: Narrow-bandwidth Television Association
Oxford Dictionaries Online
Like here: limpens.net
Using a plain old sony hi8 camera, hooked up to a video grabber running the famous bt8x8 chipset.
Nothing fancy, however the camera is able to pan and tilt via the webinterface (also some video-effects can be toggled).
Check out the apache module, written to interface between the website and the camera software on limpens.net/camera
This all works quite good, one 'engine' to grab frames when needed, and an Apache module takes care of supplying the data to all the clients and handles the video-effects.
Just buy any good old camera camera, put lots of bells and whistles on it, much more fun.
The CCD Camera Cookbook provides an excellent overview of the construction of an astronomical camera from scratch. Amateur Telescope Makers (ATMs) do this all the time to obtain high performance cameras with greater sensitivity and dynamic range than conventional webcams and Digital Cameras. Such designs not only incorporate superior ADCs but often have such features as peltier coolers.
I can still rememmber when the first reply to a problem involving hardware was, 'yes we can build it!' Now the bulk of supposed 'hackers' reply that you have to go out and buy whatever you need.
The sensor array will be a bit tedious to construct (especially if you want more than a trivial number of pixels), the response time may be slow (ISTR some photoresistors haveing recovery times in the multi-second range), and you may need to spend some real cash for peripheral equipment (if you are going to build the thing using a microcontroller, you will need something to burn the MCU's program with, which will run you at least US$100). On the upside, you can build a true greyscale device (if you use a ADC to sample the pixel photodiode/photoresistor pixels).
The resulting camera will be bulky, slow, and have absolutely terrible resolution (we're talking 1 Kpixel, tops), but, if you have a spare month or two, it sounds like a fun project.
1. Get 100, equal webcams
2. Put in an array of 10x10
3. Feed input to several computers (USB)
4. Apply respective parallel image processing, including mosaic techniques that will get rid of overlap
5. Feed resulting data to a single computer
6. Play with the resulting ~30 Mpixel image.
Don't forget to point it to the sky. You may arrange things so you have complete sky coverage, then track aircraft and meteors. Adjust software accordingly.