"Electrical trumps mechanical"
 

Hi all -

I was reading an comment/article on Slashdot today, http://tech.slashdot.org/story/14/05...n-key-just-die, in which the author is discussing whether or not the ignition key for cars are going out of style.

While the article is interesting in general, one quote stood out to me: " The push-button ignition isn't perfect, but we know electrical trumps mechanical more often than not."

This peaked my curiosity. As robot builders, engineers, designers, etc, do you agree or disagree with the authors statement? Why or why not?

Re: "Electrical trumps mechanical"
 

(Full disclosure, I work at a GM dealer and have driven more than my fair share of push-button start cars.)

The way I see it, the purpose of a car key (or fob) is to authenticate that the holder should be able to start it. If we can eliminate other related aspects that create undesirable conditions (say, having to keep the key where a heavy key fob can twist the ignition to off), it's worth a look.

Re: "Electrical trumps mechanical"
 

Electronics help mechanical stuff to move, but without mechanical stuff, electrical stuff just blinks.

Re: "Electrical trumps mechanical"
 

I'll say this since I was the victim of a rarer mechanical failure in the ignition of my Avalon. I would bet that it would have been cheaper to fix if it was only an electrical problem.

(By mechanical failure I mean that the key got stuck in the ignition and no one could get it out.)

Re: "Electrical trumps mechanical"
 

From my experience repairing things mechanical is usually nicer. It's visibly broken. Electronics on the other hand don't just fail, they get psychotic.

Re: "Electrical trumps mechanical"
 

Of course your old fashion mechanical key can be copied for a figurative dollar anywhere keys are made. Your key fob can cost upwards of a couple hundred dollars to have a copy.

Another example of mechanical verses electrical is carburetors verses fuel electronic fuel injection. A simple carburetor is cheaper & more reliable than fuel injection. As you add demands to the control scheme eventually electronic fuel injection becomes a better choice.

Ultimately this is a chicken or the egg question.

Re: "Electrical trumps mechanical"
 

Starting with such generalizations (i.e. electrical vs. mechanical control) makes for very bad design decisions. Discounting a whole set of solutions or approaches because another type is assumed to be better is fundamentally flawed thinking.

Just start with the thinking, that if your electrical is half a##, then you will have to fix it at some point. Be demanding of the electrical team, and insist on perfection.

Re: "Electrical trumps mechanical"
 

Programming is obviously the best! But honestly, electrical and mechanical are too co-dependent for one to trump the other.

Re: "Electrical trumps mechanical"
 

It can also overheat, smoke, and burst into flames.

Re: "Electrical trumps mechanical"
 

As written, the statement has no meaning, at least to an engineer. From the context, it seems that the author is saying that a pushbutton switch is a better way to start a car than a rotary key switch. Neither of these choices is inherently more or less mechanical or electrical than the other. Both are a method of closing mechanical contacts which allow electricity to flow through the switch.

In general, robots are interconnected, complex systems which rely on Software, Electrical, and Mechanical disciplines. None of these is any more or less important than any of the others. They ALL have to work in order for the robot to function properly. The best robot engineers, though they often specialize in one discipline, are familiar with and can troubleshoot problems with each of these disciplines.

That said, for nearly every electrical problem I've come across (not all), in FRC robots, cars, power tools, household appliances, automated machinery, etc., can be traced back to a mechanical root cause. For example, people on the mechanical subteam love to blame wiring and connector issues on the electricals, and take a "not my job" attitude. But wires and connectors are just the mechanical devices whose job it is to get the electricity from one place to another. Similarly, I've seen electricals say they are just responsible from the wiring diagram, and think that physical implementation of the design is someone else's problem. Neither of these exclusionary attitudes is correct. It is everyone's job to be sure that the end result not only functions properly, but is reliable and serviceable.

Re: "Electrical trumps mechanical"
 

Pssssh. Who needs programming?
http://www.youtube.com/watch?v=s1i-dnAH9Y4

Re: "Electrical trumps mechanical"
 

This is awesome! I'm going to make all my mechanical kids watch this next year.

Re: "Electrical trumps mechanical"
 

Fascinating stuff. Well found, sir! :)

Re: "Electrical trumps mechanical"
 

Mechanical solutions can come in 1 of 2 categories:
1)actuated: These are basically the same as electrical solutions but a human moves the part instead of an electrical thing that adds an additional layer of complexity.
2)passive: Passive is always better.

the difference is wether code does the logic or a human does. Users tend to find 'electrical' solutions which are really electro-mechanical to be more appealing but a pure mechanical solution has one less part that can fail.

This isn't true in all situation and I do have an engineering bias but yeah...

Re: "Electrical trumps mechanical"
 

"Electrical trumps programming"

- I say this because, would you rather have a simple set of switches / simple circuit for something like your range hood, or have to reboot the thing when the OS crashes? There are certain things programmers should be kept away from.

*I say this as a programmer.

Re: "Electrical trumps mechanical"
 

Engineers of earlier generations can be incredibly inspiring. I'm not sure which of these is more impressive:

1) The methods described in the video linked above were used to sink the Bismarck and destroy the Japanese carrier fleet at Midway,

2) The SR71 was developed by guys in crewcuts wielding slide rules and French curves, or

3) NASA got astronauts to and from the Moon using less computing power than today's toddler has in a LeapFrog.

--------

Oh, yeah, electrical totally trumps mechanical. But it was not always that way.

Re: "Electrical trumps mechanical"
 

Or is this history repeating itself?

Maybe I'm older then most of you, but I remember cars having a big silver (chrome) button on the dash to push when you wanted to run the starter. It was considered modern because it was better than getting out and turning the crank at the front of the engine.

There was also a switch, later a key switch for security, to turn on/off the electrical system.

The present-day ignition switch on the steering column came about as a mechanical interlock to prevent turning the steering wheel unless the key was inserted. It was a crude theft-prevention system that was easily defeated with a large screwdriver or dent-puller.

All the electronics in cars now makes the mechanical aspect irrelevant. You can no longer rip a hunk of wires from under the dash and twist the ends together to steal a car, even if the movies say you can. You can't steer a car very well without the engine running either, so that interlock is irrelevant. And it would be trivial to interlock the transmission to the electrical system and make it impossible to drive without the systems permission.

Keys with chips, or just a chip on a piece you keep in your pocket is all that is needed now. For that matter, they could use NFC or Bluetooth and let you authenticate your permission to drive with your smartphone. It already ties into everything else, why not?

Stealing a car has gone from splicing wires to hacking.

Keys may be nearing obsolescence, but they still give the owner a good feeling. They want to know their expensive car is locked down. And what do you use to get into the car when the battery dies?

Re: "Electrical trumps mechanical"
 

The push-button start and key start of modern cars both involve the same amount of electronics. If you turn a key on a new car for more than 20 seconds, the starter automatically stops. The same thing happens if you try to start a car that is already running.

The key on my car lets me turn on the radio, start my car, stop my car, and remove the steering wheel lock. On the steering column, there is a device that allows me to lock my steering wheel when I have the key out, unlock my steering wheel when the key is in, and shift out of park when the brake pedal is pushed and the key is turned. Just like the doors and locks in my car, the system has never failed. The system is simple, and works every time, even after 230,000+ miles of driving. Why fix what isn't broken?

Re: "Electrical trumps mechanical"
 

Point of data: Even the cars today with keyless start still have a key capable of unlocking the vehicle, and there's a sweet spot where a nearly-dead remote will still be recognized. In cases where there's no key lock on the door (say, the Cadillac ELR that uses touch pads), there is still a procedure to get a door open and start the vehicle. (Source (PDF), pages 2-7 and 2-12)

Re: "Electrical trumps mechanical"
 

Electrical trumps mechanical like apples trump oranges.

Re: "Electrical trumps mechanical"
 

In my limited experience in the sheltered world of an FRC team, I would make the argument that mechanical failures are generally easier to find while electrical fails are easier to fix. I know when a mechanical thing breaks, it usually takes lots of time to fix. Perhaps we go out to a match or 2 with it broken. I can fix most electrical problems in queue.
Perhaps that's because the electrical systems are designed by paid engineers, with more resources, and mechanical systems are designed under extreme time pressure by robotics teams, including high-school students.

That being said:

Re: "Electrical trumps mechanical"
 

(Bold added).

While I have to agree mostly with the "apples trump oranges" comment, and also agree with the fact that a carb is simpler than fuel injection, I've driven my minivan 120,000km and never had to touch the fuel injection. Related to that I've never had to change the spark plugs, either. I don't know if I've ever got a carburated vehicle to go a decade without needing either new plugs (from the inefficient fuel mixture) or simply tuning. And don't even get me started about carbs gunking up when they sit around unused for a while.

But aside from giving a shout-out to those who design the awesome engines we get to enjoy in modern vehicles, let me suggest that the reason that we get so excited about advancements in electronics and controls is not because they in any way "trump" mechanical technologies, but because they are newer. The many brilliant mechanical solutions we have for problems, from cams to transmissions, have evolved over -- in many cases -- centuries. We're used to seeing them and thus tend to take them for granted, while newer developments that make them more efficient or precise are considered more exciting.

I love the technology in the Tesla cars... but they'd kind of suck if it weren't for ball bearings, eh?

Jason

Re: "Electrical trumps mechanical"
 

Pro tip, your key chain that has your ignition key really shouldn't have anything other than the car key, the remote fob and maybe one house key. That extra weight increases the wear on the tumblers and can lead to the failure you describe though the more common failure is that the key won't turn the ignition lock cylinder. Note many will tell you that you shouldn't have your house key on there in case someone car jacks you since you likely have the registration in the glove box and that registration likely has your address on it.

Well the majority of cars nowadays have transponders in them and they can get expensive to replace depending on the brand of the car. Not only the key itself but many need a scan tool to program the car to accept then new transponder's code. A friend bought a used Honda that came with a single key, he spent $120 to get a second key and have it programed. On the other hand if you have a Ford or Chrysler product and you've got two keys you can program more keys yourself in about 30 seconds. Purchase one online and get the key person and your local hardware store to cut it for $1 and you've got a new programed key for under $20. Many locksmiths and hardware stores will also clone an existing key for $50-$60.

Not all newer cars work that way. Yes some are set up so that turning the key to the crank/start position sends a signal to the power train control module. The PCM will usually then ping the transponder to see if it is a key that is registered in its memory and then check if the engine is running. If it determines the key is valid and the engine is not turning it will then operate the starter until it senses that the engine has started or for a predetermined amount of time. However there are still newer cars out there where turning the key to the crank/start position just sends a signal to the starter relay and the starter will run as long as the key is in that position, even if the engine is running.

Many modern cars don't have steering wheel locks anymore, the thought being that since you can't hot wire it due to the transponder in the key the lock is not needed. On the other hand some cars have transponder bypass modes so you can start a car in instances where the transponder system has failed. They commonly require you to enter a code via actuating switches that don't seem related to starting the car. Here is the process for Honda built vehicles, I'm only posting this because the "code" is unique to the vehicle and normally only available to someone at an authorized dealer to look up. http://automotiveandcommerciallocksm...edure-for.html

Then there is the case of snooping and capturing the transponder code, cars with push button start where you can leave your key in your pocket are most susceptible to this. Their transmitters are often motion activated so while you are walking along with the fob in your pocket you are sending out the code. The older transponder in the physical key is less likely to be able to have it's code snooped since it requires a very near magnetic pulse to cause it to transmit.

Re: "Electrical trumps mechanical"
 

After having both, the keyless start is a big pain because:

The 'stand next-to-the-door-to-unlock' doesn't work half the time. Gotta take the fob out. At that point, might as well have a slot to put it into and turn instead of a silly two-push button system that cycles through modes, when I could very clearly tell how far I had turned a key... and then awkwardly put the key fob somewhere not-buried so the car won't bing at me for not detecting a key.

Big picture is important. If it doesn't add any value such as security, ease of use, reliablility, while increasing implementation complexity and cost, why do it?

Only issue with mechanical keys is occasional jams.
Might be me but we'd be better off developing a better lock.

Or better yet, full keypad system? Punch in to lock/unlock, then once you're in it's yours.