Hi Snowman,
Thank you for the links about form factor.
Its not a term i am familiar with.
The input pattern on a priority encoder gives a sort of 'ramp'
or 'slope' similar to the way you describe the light falling
on the array of sensors.
The table attached shows nine inputs, position ten or zero is
when all inputs are high.
The inputs are held high by pull-up resistors,
and active low takes them down.
The interesting thing is that the inputs are 'prioritised'
thats what the 'X' is for, the inputs of lower priority are
ignored.
If you aren't used to looking at these tables,
then just look at the middle row,
the row where 5 is marked as a low.
It gives the binary output for 5 thats fine.
What you can also see is that inputs 1,2,3 & 4 can also be low.
Cos they're marked with 'X's
Thats what i mean about the similarity to the row of sensors
you described, with light falling on a portion of them.
I was looking into an arrangement using this kind of thing.
I'm still thinking about this,
Would it be a problem to have two rows of sensors
instead of one ?
that might make circuitry easier ...
John