Haha yep, _some_ jugglers can juggle with their eyes closed, though---even with 10 years of experience---I've never been able to get more than ~10-15 catches of 3 balls when I've tried it myself - it's not easy! What you're suggesting would absolutely work in theory, but I think putting it into practice would be quite challenging. The problem of wind that you've identified would absolutely be a show-stopper if jugglebot were (visually) blind.

@@harrisonlow That's probably where you can use the Kalman filter: to combine the location prediction from the model (from the forces) with the measurement (from the camera). Both have errors but are more accurate when combined.

@@Ray-jy9sf I agree that jugglebot would be more accurate _in theory_ if it had force sensors in the hand and was able to combine those readings with those from the eyes, though I wonder how well that would translate to real-world accuracy gains. I say this for two reasons: 1) The camera-only approach _should_ be quite accurate if the balls are being thrown any appreciable height. I say this because projectile motion is a very well understood process and if the "eyes" are sampling at, say, 100 Hz, I would expect them to be able to average out any errors and give a very precise prediction of where the ball will be at any point in the future (until it changes path). 2) My (somewhat limited) experience with force sensors is that they are quite noisy and I have no idea how I'd mount force sensors to the hand to get a meaningful reading. There are some specifics here that relate to the "brain" part of jugglebot and how the juggling model works, which I haven't discussed in any videos yet, so there are undoubtedly many questions you have along these lines. I've been wracking my brain for a while now trying to figure out how to best present that content because it is quite detailed and dry... Perhaps I just need to bite the bullet... I like the suggestion of a Kalman filter! I have never used this approach myself, but I read into them quite a bit a few years ago and they seem very interesting. Let me know if you have any other suggestions or thoughts on this!

Haha I like this take!