This Instructable will show you how to set up your webcam so that you can use a torch as a mouse. This will work better at night but you can still do it during the day.
What you need:
A webcam, Any webcam should work.
A torch, if you don't have one you could try using a laser pointer or the flash from an android phone.
Webcam signature, downloaded from here.
Before you open Webcam Signature, go into your webcam settings and turn of all the auto features, eg auto white balance.
Then put the contrast on full, brightness a little over halfway, colour intensity at none and exposure and gain at none. If you can't find all of these settings just fiddle around with the ones you have untill all you can see when you shine the torch at the webcam is a white dot like in the picture, or something similair.
Once thats done, extract Webcam Signature and run the .exe. Find the "Fine Tune Tracking Colours" Button and change the settings like in the picture, all the high colours on full, and all the low colours at almost full, if your using a colour other than white, shine it at the webcam and select "grab frame" then click on the colour you want it to track.
Now you can play around with the red square on Web Cam Signature, hold down Ctrl+Shft to draw a line. Remember to always keep the torch pointed at the webcam. When you've got the feel of it go ahead and check "Webcam Mouse" Now you can go draw stuff on paint or do some other artsy stuff. Remember, you will still have to hold the mouse to click. Moving back from the webcam will increase your accuracy and moving forwards, speed.