Over the weekend I got a reminder about the value of mechanical switches in some human-machine interfaces. People cannot do everything, nor should they, through a display, touchscreen, and a few pushbuttons.
We have in-ground sprinklers that water our lawn in eight zones. Three other zones handle drip-irrigation lines to shrubs, flowers, and ground-cover plants. Several years ago a landscaper installed a commercial sprinkler controller that lets me set the time for the sprinklers to start a sequence, the length of irrigation time for each zone, and three possible "programs." The controller provides three pushbuttons, a rotary switch, and an LCD. I find that human interface annoying and limiting.
Most of the time the system runs through all 11 zones every few days. At times, though, I want to run a special sequence of, say, zones 3, 4, and 7 to water areas that look particularly dry. The next time I might need to water only zones 1, 2, and drip lines in zone 11. To run such sequences I must select one of the three programs, turn each of the 11 zones on or off by using the rotary switch, pushbuttons, and LCD, run the special sequence, and then return the program to its original state by again going through the zones, one by one. (I rarely vary the watering time for zones, so that's not an issue.)
It would have helped if the manufacturer had provided a set of switches so I could quickly and easily select a few zones and run through a cycle to water only those areas. At the end of the cycle I could change the switch settings so the next cycle would go through all or a few zones. But the controller doesn't provide that flexibility. Although the controller manufacturer has newer units, they still lack the capability to easily turn zones on or off temporarily without having to go through programming steps. An Internet search located many controllers, but all have the same type of interface and limits.
I thought about a design for my own controller that would offer all the "bells and whistles" needed, but after sketching a few ideas, creating a rough flow chart and list of software functions, and thinking about the time needed for a one-off project, I abandoned the idea. There had to be a simpler way to solve the problem.
Then a solution came in a flash -- intercept the valve-control signals that go from the controller to the individual water valves and insert an SPST switch for each signal. Then the controller can go through its regular cycle for all 11 zones, but the switches control the water valves that actually operate. This type of external retrofit solves the special-cycle problem and requires only an external box and switches. I can add it to the circuit without much work. I might include an LED for each zone so I can tell at a distance which valve has power. I have LEDs and switches on hand and just need a plastic case.
The controller manufacturer could have included this type of capability, or at least offered it as an add-on product. Simple mechanical switches triumphed over an overly complicated "simple" user interface.
What's wrong with MOVs that interupt the actual flow of water in the lines? They are easily understood by even the dimmest of the unwashed masses. They work even during power failures.
The issue is appropriate technology. Sometimes that means very little technology at all. If these companies had a brain, they would provide something simple at the same price as now and sell their complicated unit at an additional price. They would limit support issues and make more money.
Engineers are not immune to the "See How Clever I Am" syndrome.
I work for a large healtchcare system and one of our ongoing challenges is helping nurse users struggle through multiple layers of menus to set up medical equipment. The equipment is designed by people that love technology for people that don't really care about how 'cool' it is; they just want to take care of patients. Simply put, nurses are people focussed, we tend to be equipment focussed.
Perhaps we can all learn a lesson in user interfaces from this.
Charles Murray, you're absolutely right about that.
I own a 2008 Saturn Astra, and I'm completely unable to set the clock without referring to the owner's manual. I can never remember the steps required to get to the clock controls via the car's "Board Computer" and display, because it's not something I need to do very often.
I also own a 2011 Kia Sedona, and it's very simple to set the clock: push the "Hour" button to increment the hours, and push the "Minute" button to increment the minutes. That's the *right* way to design the controls for a car's clock.
Well, Chuck, the UI can be better. I have the same brand of sprinkler system. I find it interesting that the controller box in the picture looks fancier more colorful, but is EXACTLY the same as the one I have. I guess that in a business like this, the core competency is not the controller, but the system parts. There are lots of controller electronics and displays that would make this easy and do what Jon wants. On the other hand, Jon's solution is a good one. We have exactly the same problem.
Good luck finding a car without confounding electronics, Jon. Some of those electronics, though, can be pretty handy. Some are annoying, though. My Taurus locks the backdoors when I turn off the ignition. If I have passangers or packages in the backseat, I have to remember to unlock the doors before exiting the car.
I did almost the same many years ago by placing a single switch in the common lead to the sprinkler valves. Where I live, we frequently have a few consecutive days of morning showers. During those days I open the switch thus disabling the valves. During the drier days, I close the switch and watering resumes as programmed. I located the switch indoors to make it convenient. More recently, I replaced the switch with a relay. The relay is connected to a low-power embedded web server. I can now control it from my iPad.
True. In a few years we'll probably look for a new car. I hope to find one without all sorts of confounding electronics. I like gadgets as much as anyone, but they shouldn't stand in the way of getting things done as easily as possible.
Jon: The dilemma you cite -- putting all the bells and whistles in software -- is one that has confounded the auto industry, too. Doing such things in software, you end up with a series of nested menus and a manual in your lap.
When your lab is only one scope, one meter, and one homebrew function generator and power supply, the scope is stage center. But this one wasn't working right.
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