This build season while programming our 5 ball, we found that confirming balls were shot so the robot could transition to the next step in our autonomous sequence wasn’t particularly reliable. We attempted reliable detection using motor rpm, but found that it was difficult to tune due to inconsistencies in our shooter design. Now while doing this, we found that using external sensors (colour sensors, switches etc) were reliable, but added weight and also would detect the ball before it being shot, so a ball getting stuck was an concern.
We found an efficient solution in the use of the limelight. Our limelight sat directly behind the shooter, so the arc of the ball would cover the target from site for roughly 60ms. Using the same logic as a switch, we allowed it to detect when balls were shot and out of the shooter on their way to the hub. With a properly configured limelight this had almost a 100% success rate.
From here it’s a ramble so just ignore this if you’re not interested
While this was only used by us this season in auto (it was implemented late season), this could have many interesting uses. We used it to detect if we SHOT balls, but it could be used to detect scored balls (by running a check on tx and maybe the associated shooter speed for the distance?) There are quite a few interesting things that could be done with this and I’m interested to see how it could be used
Yeah this may not be relevant to many teams but I thought we could share it anyway in case anyone found it useful/interesting.