optical mark recognition

[k2thedevil]

can anybody tell me how to build an Optical mark recognition thing
black dot detection basically

 

[Nigel Goodwin]

can anybody tell me how to build an Optical mark recognition thing
black dot detection basically

Your requirements are rather vague?, but you can detect black on a light background with a simple LED and phototransistor (or photodiode). Reflective opto-couplers are freely available, which include both in a single package, and could well do what you want?.

 

[k2thedevil]

Your r right Nigel and thats primarily because I m new.
could u give me some links to sites offerring circuit designs for this problem
or if u know a circuit urself
i basically would like to detect a black dot on a white background
with minimal components and modest accuracy

 

[Nigel Goodwin]

Your r right Nigel and thats primarily because I m new.
could u give me some links to sites offerring circuit designs for this problem
or if u know a circuit urself
i basically would like to detect a black dot on a white background
with minimal components and modest accuracy

Try searching for line following robots - they use the same technique to find and follow the line.