|NASA's Orion Spacecraft|
|Avid S3 Mixing Console|
You grab hold of a rotary control it is easy to tell how far you have turned it, even if the knob is on a radio mounted in the dashboard of car that is bouncing down a pothole filled road. Try adjusting a slider under those conditions and you can't, not with any degree of precision. You can't even adjust a slider accurately without being able to see it so you can tell how far it has move. Okay, maybe this is a personal problem. Maybe sliders don't cause you any difficulty.
I've been having trouble with Cruise Control in my truck, and now I'm having the same trouble with the power locks in the Hyundai. The problem is that sometimes when I push the button it does what it's supposed to, and sometimes it doesn't.
I think I figured out what the problem is. When I first got these vehicles, when I pushed the button, I would wait for it take effect before I released. It doesn't take long for that to happen, a few hundredths of a second, I imagine. As time goes by and I become habituated to the way these controls work I start releasing that button sooner. Since this shit is probably computer controlled, there isn't a direction connection between the switch and the device, everything goes through the computer, and the computer is scanning all the controls and it can only do it so fast, so if you tap the button and the computer isn't looking in that millisecond wide space of time, it will miss and it will appear that the switch is flaky. So you have to adjust. You have to hold that button down for just a little longer, long enough for the computer to register your tap.
Problem is that sometimes your tap comes at just the right time, and even though it is really quick, it happens to fall in that window when the computer is looking and so it works fine.
I don't like these touch screens, no tactile feedback, you have to look at them to tell where to put your fingers, and they all seem to require different amounts of pressure. Knobs and switches are what I grew up with and if they were good enough to win the great war, they ought be good enough for going to Mars.
Mechanical switches do have problems with reliability, they're mechanical and mechanical things wear, and eventually wear out and fail. The design and construction methods employed in building our spaceships determine their life span. Sometimes they don't make it that long, but sometimes they keep going long past their expiration date. If you have your choice of a component that will wear out and one that won't, it's probably a good idea to use the one with the infinite life.