As my first project in the area of electronics, I am designing and building a silhouette camera. A matrix of LDRs captures the shadow of an object, and it is then displayed on LEDs. The image can then be saved, and more can be taken.

Here is my first draft of a design:


I use dot matrices in order to scan through both the LEDs and LDRs in order to remove the need for excessive use of PICs.

Question 1:
I am trying to find a suitable counter. I have posted here: 16-bit equivalent of the 4017 IC?

Question 2:
I am trying to change the output of the counter to either 1 to 0. I have used a crude method for this (a transistor hooked up to the anode of the counter) which I believe will not work very well, due to the fact that this would just reset the counter at the same time. Any solutions?

Question 3:
I am planning to use a PIC16F627 for this project. If there are any more suiting, please let me know.

Along with these questions, I am also looking for any other general feedback. Thanks for reading!

I have solved question 2 by using a few And gates.

Here is a circuit diagram using the 4017, and so the matrices are only 10 by 10. It has been slightly tweaked in other ways as well:



Question 4: Is it possible to have only one resistor being used for the LEDs as the counters scan through them?