Hacker News Reader

I live in central London in a 3-4 years old building (24 floors) and the elevators are truly a joke. Every 3-6 days they somehow get out of sync with which floor they are currently on, especially if you go first to -1, after that pretty much every floor will be wrong :) I always wonder who wrote it.

View on HN

I know a guy who built an elevator system single board computer to control it. The big problem was the power to the board - the motor turning on and off and the old electrical system made it very spiky, which would cause the computer to glitch. He built in a lot of self-checking in the computer, but it would still fail once a day or so. He eventually fixed that by having the computer just hardware reset itself regularly.

Was there any particular reason that the problem could not have been resolved through hardware since the hardware was a new development?(i.e. a UPS or better filtering?)

The customer refused to resolve the issues with the electric power. My friend did add lot of filtering, but said he'd reached a limit.

It's probably trouble with the sensors in combination with bad capacitors, which cause the motors to not accelerate the elevator at the rate which it is programmed to expect, so it doesn't quite exactly know where it is. Tldr it's glitchy.

Reply on news.ycombinator.com