Nice, I bought a pi to make a &quot;cat on the kitchen table&quot; alarm to handle a common problem. Have not had time to complete it, but the concept is: find the pixels that compose the kitchen table-top and get the convex hull of those. Next identify pixels that are &quot;cat color&quot; and are inside that hull. In the case of my cat, &quot;cat color&quot; is several colors and stray matches can be rejected if they are not near different colors in the collection - false positives are bad, as we don&#x27;t want to turn it off during dinner and people have different clothes all the time.<p>Another challenge is scaring the cat out of the christmas tree. This will be coming up soon so I may have to finish this thing after all. Training the cat to stay off the table has gone well, since we keep interesting stuff off it when we&#x27;re not there. The tree however is full of interesting stuff.<p>EDIT: to clarify, I never completed the table project, in part because it&#x27;s not a problem any more.