As part of a sorting machine, I need to orient a pile of plastic brick-shaped objects (which are all identical in size - about 3cm x 2cm x 1.5cm) so that they always end up with the white side facing up:
These will then be fed into a bowl feeder type of machine for further re-orienting.
How can I accomplish this, preferably without optical sensors? I was thinking about cutting into the bricks and putting magnets inside, but is there a more elegant solution?