A couple of months earlier, my tutor Mr.Shafeek rang me and asked how he could connect his laptop onto his television so he could watch movies on his big screen. He had brought a locally available "S-Video to RC cable" for 300 Rs and the thing didn't work. I assured him that I would find a solution and report to him at the earliest.
At the same time I was hunting for a circuit to convert VGA signals to composite video so that I could see my desktop on my TV screen. So I Googled it and came up with a simple, low cost solution to do S-Video to CVS(Composite Video Signal). I discussed this with my friend Arun.K.V and he too expressed interest with this small project for he was also tired of watching movies on his laptop LCD display.
Teaming up with him we first went to our local electronics market- Thakarapparambu road - where there are plenty of shops selling electronic components. To our dismay, all the shops offered an S-Video to RCA cable which costs between 100 to 500 Rs depending on the quality. When inquired, a salesman asked "You want S-Video to 2 RC or 3 RC???". We were dumfounded for a TV had only one CVS- RCA socket and the rest two were intended for stereo audio channels.
So we purchased an S-Video plug, an RCA plug, wires and a 470 pf capacitor (pretty small circuit). Again this costs between 60-100 Rs depending on the quality. Putting together everything according to the circuit diagram, the assembled cable worked fine and we saw a very lively, bright display of the desktop on the 21-inch TV screen. Laptops with S-video ports also have configuration menus to adjust the display on the TV.
Presenting the cable to Mr. Shafeek sir, it is needless to say he was delighted. A DivX movie played on the TV screen resembled DVD like video quality.
The same site which I googled up also had the circuit I was looking for - a VGA to CVS converter. As convertion to CVS involves generation of timing signals the circuit is a bit complex, but can be built.
Here is the page for the S-Video to CVS conveter: http://www.epanorama.net/circuits/svideo2cvideo.html
VGA to PAL and NTSC: http://www.epanorama.net/circuits/vga2tv/vga2palntsc.html