Dear Ben,
Your seeing-eye hat got me thinking about a build I'd love to have you tackle. We have several rescued cats that are allowed to go in and out at will. In the summertime, we sometimes leave the sliding door open a little so they can go have their adventures without troubling us to use our opposable thumbs to help. The real trouble is keeping track of them all as they come and go so freely.
The idea for the build is a small, cat-wearable sensor (perhaps on a collar), that could be read by a door-mounted sensor. Each time a cat passes by the door, it would capture the fact. The data would be simple -- pass the sensor once, the cat is out; pass the sensor twice, the cat is in (always assuming the cats start inside). Odd numbers of passes = out, even number of passes = in. The trick would be to have the door sensor detect each cat separately. Something like different colored LEDs might tell us which cats remain outside, which are safely in.
I figured this build would not only be useful, but a great way to combine your electronics expertise with Alyson's cat-loving expertise. Thanks! Love the show!!
John
