Take an old LCD screen (small). Take the back out of it. Put a (grayscale) single-pixel sensor in behind it.
Then repeatedly display random hash on the screen and take a measurement of the light intensity. My intuitive guess would be that you'd get the most info with half the pixels on fully and half of them off fully, randomly chosen, but I can't say why.
You should be able to get much the same result as this, without any moving parts. Although you'd have to use an entirely different transformation to get there - it'd reduce to a (massively) underspecified system of linear equations to solve, with noise added in to boot. Have fun with that.
Take an old LCD screen (small). Take the back out of it. Put a (grayscale) single-pixel sensor in behind it.
Then repeatedly display random hash on the screen and take a measurement of the light intensity. My intuitive guess would be that you'd get the most info with half the pixels on fully and half of them off fully, randomly chosen, but I can't say why.
You should be able to get much the same result as this, without any moving parts. Although you'd have to use an entirely different transformation to get there - it'd reduce to a (massively) underspecified system of linear equations to solve, with noise added in to boot. Have fun with that.