My stepson has one- and I was astonished how good it is. I can’t say I’ve thought about it at length but at face value it seems a marvel. Is the logic for such a thing trivial and widely available?
• Choose some reasonable number of questions of the form "Is it ___"?. Let's say 256
• Come up with a list of objects, and for each one give it a 256-long bitvector encoding its answers to the questions
• Maintain a set (implemented as another bitvector) of the potential items. Figure out which question would divide the set in two most closely; ask that question.
I am the opposite of a hardware hacker or systems programmer, but it seems like this is algorithmically straightforward to implement with bit-twiddling.
Actually programming the logic once you know it is the easy bit, it's constructing the dataset of answers and questions in the first place.
This depends on the goal. One goal might be to answer all questions as quickly as possible, in which case partitioning the search space in two might be a good strategy. Another goal might be to have the best chance of guessing the item within 20 questions, in which case you will want to choose questions which maximise the % of the remaining search space you can uniqely identify with the remaining questions (perhaps weighted by popularity of that item).
It's a neural net, so very efficient on small devices.