London, ON
Quoted from Jgaltr56:I sell sensors for a living. It all comes down to cost vs performance. I think the missed balls have more to do with the range and how the sensor is located under the playfield. Like Mike said, inductive sensors with enough range to detect the ball through a 1/2" playfield reliably will be much more expensive than a micro switch. It's also more complicated to locate because any other metal in the vicinity of the sensor and the iron content of the ball can affect range. It looks like Heighway designed their own sensor to keep cost down and also counterbored the backside of the playfield to reduce range to the ball. It's not perfect, about 1 ball out of 5 gets missed on my Full Throttle's fast inner loop (all the other sensors work 100%). There is some adjustment which seems to help but there is just too much variability to get it up to 100%. I also believe the CPU struggles and the scan time between inputs may be too long. Just speculation on my part.
When I spoke to Romain Fontana from Heighway (pre 2016) he said the sensors were on their own boards - self calibrating and buffering their data (independent from CPU scan rate)
