For continuous monitoring of the sun, I dare not to use my DMK 31AF03 since it's pretty expensive, I don't want to risk it dropped, or to suffer from the prolong exposure of solar light ray, so I need a cheaper camera to do the job.
On searching around, black and white cameras are not easy to find, options are:-
1. CCTV camera from ebay
2. Meade electronic eyepiece
both can be used with frame grabber, the resolution is lower and the price is far cheaper too, it makes them very suitable for this kind of usage. During the studies, I found that the video signal is called composite video in general, and it can be carried by cables with BNC (plug, twist and lock) or RCA (direct plug in, those yellow plug) plugs. And convertors between BNC/RCA plugs are readily available at quite cheap price.
Finally, frame grabber is pretty cheap nowadays too, and they can be used for non-astronomy purpose as well. Sounds like a great option to me.