noel1983 wrote:What about a beam break sensor? That would stay broken for a small post card ...
That would probably work well in a small mailbox. However, the typical french mailbox, like mine, is~ L 300 x D 410 x H 300. So, if the beam were in the center of the mailbox, from floor to ceiling, it would be easy for a letter to land outside the beam. Also, I would have to mount one side of the beam in or under the floor.Something that would cause problems at some point.
However, I could mount both emitter and detector on the ceiling. One at each end of the box, and angled towards the center of the floor,
Something like:
- art_019_obstacle.png (21.09 KiB) Viewed 2509 times
The question is: Would a small envelope cause a significant enough drop in reflectivity to "break" the beam? However, rather than using a binary on/off IR detector, if I could find one with analog output I might be able to determine changes. Worth looking into.