Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: Ninten-doh on June 05, 2006, 09:47:08 pm
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This is probably a really dumb question, but I want to be sure. I recently purchased a 2 1/4" Happ USB trackball and it has the green grounding wire that stick out of it. I thought that the USB connection would ground the unit, no? Is grounding the green wire still necessary?
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This is teh GOOD QUESTION
NO you do not need to ground that sucker. Infact, just take the green wires off all together.
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Necessary.. depends who you ask?
I think my opinion is in the minority, but yes ground the trackball. Ground your trackball, your spinner, and anything else that may need it.
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Why?
and
how?
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I was about two days away from asking the same question Ninten-doh.
Basically, according to the Optipac instruction page, it just attaches to any ole piece of metal to prevent static build-up (the same reasons you would wear a wrist strap, or at the very least, touch a piece of metal, before working on the insides of a computer).
I was going to ask because I have no convenient way of attaching it to something (panels swap out). I was just going to screw it down, hide under a blanket, cover my eyes and hope that somehow, everything turns out okay.
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I don't get it...The USB cable contains a ground (along with a +.5v and twisted data pair). Why would you need another ground.
Also, for a wrist strap to work, the bench must be grounded. Attaching a ground wire to "any ole piece of metal" wouldn't necessarily be effective at dissipating static.
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In theory, it's supposed to be attached to something inside the cab that is in turn connected to earth ground. Lots of people skip it, but it certainly can't hurt to hook it up if it's not too much trouble.
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Signal Ground does not equal Earth Ground.
Depending on where you live(i.e. you shock yourself a lot in the winter) you can build up a charge touch your spinner, trackball, etc and 2000 volts get's sent back to your PC. Not good and your PC won't take that abuse for very long.
A simple, Good enough for Gov't work, way to ground everything is to connect a wire to one of the mounting screws of your PC's Power Supply. The Power Supply case is connected to your AC earth Ground and it will dissipate back into that. I like to use one of those ring terminal crimp connectors and just slip it over the mounting screw, but whatever works for you. I attach the other end to the trackball and to a mounting screw for my spinner. If you use a modular panel, it's only one more wire to connect.
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The green grounds are for dissipating static charges in the rollers ... there are those who will say that you don't need to connect them and Happs support has been known to say that you really only need them in dry climates.
I connect mine -- compared to the entire cab-building process, it is the most minor of inconveniences.
Cheers.
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I was going to ask because I have no convenient way of attaching it to something (panels swap out). I was just going to screw it down, hide under a blanket, cover my eyes and hope that somehow, everything turns out okay.
Couldn't you make a simple contact point on your panel where it attaches to the cab ? Like the contacts used in old (e.g. before magnetic contacts) alarm systems to detect if a window or door is open. The panel side would connect to the earth ground on your TB while the cab side would connect to an earth ground in your cabinet.
Having said all of this, I notice that even Bob Roberts has suggested that earth grounding may be more trouble than it is worth:
FAQ: In most of my games the earth ground ends at the AC filter & does not tie the metal cab parts together. What's the deal here?
Yes it's true that inert cab metal grounding is often nonexistent or it has the CP excluded due to minor shocks between games when one is improperly wired... it has the monitor frame excluded due to herringbone interference presenting itself on the screen... it has the PS excluded due to chattering &/or interference, and there are many varying opinions on this within the industry & all I can say on that is that any shocks that I have gotten from inert metal vid game parts since their inception, has been from earth grounded pieces. I have never received a shock from an inert vid game metal part that was not tied to earth ground!
http://homearcade.org/BBBB/buildit.html
Cheers.
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Couldn't you make a simple contact point on your panel where it attaches to the cab ? Like the contacts used in old (e.g. before magnetic contacts) alarm systems to detect if a window or door is open. The panel side would connect to the earth ground on your TB while the cab side would connect to an earth ground in your cabinet.
Yeah I was thinking about doing something like that. It doesn't have to be something complex - maybe just two metal contacts. Static Electricity is not a big problem around here though, so I'm not going to sweat it too much either.
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AFAIK, the ground on the TB is to ground the rollers'/ball's static build up from arcing to the sensors. It is NOT to directly ground you. Static can tranfer from you to ball to roller, but won't be fast (in electronics speeds, that ball isn't a good conducter after all). However if the static on the roller isn't discharged with a wire, it can build up and in rare cases damage the sensors. Add that the ball rubbing on the roller (and you touching the ball) can cause static build up and ... it might build enough to zap.
BTW, I don't hook up my TB ground, but it's not cold nor dry enough here most of the time. ;)
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AFAIK, the ground on the TB is to ground the rollers'/ball's static build up from arcing to the sensors. It is NOT to directly ground you. Static can tranfer from you to ball to roller, but won't be fast (in electronics speeds, that ball isn't a good conducter after all). However if the static on the roller isn't discharged with a wire, it can build up and in rare cases damage the sensors. Add that the ball rubbing on the roller (and you touching the ball) can cause static build up and ... it might build enough to zap.
BTW, I don't hook up my TB ground, but it's not cold nor dry enough here most of the time. ;)
That's what I've always heard and I can't argue with that, but don't forget about the trackball mounting plate. It's been a long time since I've looked at a trackball taken apart and looked how, but it get's grounded through the ground wires as well.
Like I said, I'm think I'm the minority in saying to use them. But search the forums, every once in a while someone will say I touched my spinner and my PC died. It's not often, but it happens. If you live in area where you don't shock someone, maybe you don't need to. I've always lived in an area where it happens.
Plus aren't all metal objects in a real arcade machine grounded. ;)
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As has been pointed out.... Signal ground and earth ground are two different things......
Earth Ground: Grounds all metal components so that any dangerous voltages which can occur during a mains power short circuit, are carried away to Earth through the green wire and not through the person who comes into contact with them.
Signal Ground: In most cases deals with Low DC Voltages and is just the return path for the signal. Mostly it's not really a true ground but just connects to the negative rail of the supply. It's effectively at a floating voltage, and not 0V "True Ground".
SO!! If you have a metal CP then you should definitely connect the green wire to the earth connection (grounding tag) of the mains supply or to the panel which should have a grounding wire so connected, for safety reasons.
Best Regards,
Julian (Fozzy The Bear)
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Thanks for all the info guys! What I still don't get is why a normal USB trackball mouse used for Windows, etc. can simply be plugged into a PC, but an arcade trackball needs the grounding. Is the key to all this what Fozzy just said...
"If you have a metal CP..."
Since the normal trackball mouse is encased in plastic it doesn't need the ground, but if the arcade trackball is attached to metal it needs the ground?
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A PC trackball doesn't use metal rollers.
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A PC trackball doesn't use metal rollers.
Ahhhhhhh. Thanks!
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I was going to post this a while back, but never did for some reason.
The green ground wire for the track ball being used as a means of protecting the electronic circuitry inside is a somewhat silly notion. The boards are grounded and a good distance away from any metal parts that might be able to send any juice to sensitive parts. The amount of static energy required to jump those distances would be huge, and not likely to be generated by spinning a plastic ball against a steel roller.
The ground wire is indeed there to prevent static energy build-up in the ball, but not to keep you from getting a shock either (although this is probably a side benefit).
A trackballs biggest nemesis is dirt and debris. It causes them not to operate smoothly, causes premature wear on the rollers and too much of it floating around inside the case can even mess with the optics over time. Nothing attracts dust and debris like a piece of plastic with a static charge. Debris sticks to it like it's a crud magnet.
So the real answer is: No, you do not need to hook up the wire, but it is a good idea to do so if you want the unit to stay cleaner, perform better and prolong the life of your rollers.
Can we finally put this one to bed now? :)
RandyT
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Can we finally put this one to bed now? :)
I dunno, can you prove any of this?
:o
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Can we finally put this one to bed now? :)
I dunno, can you prove any of this?
I can prove that small amounts of static likely to be generated by a plastic ball rubbing against a steel rod can't jump the one inch distance to the electronics. You can put on your best static generating clothes and roll around in shag carpet on a hot day in New Mexico and still you need to come within a tiny fraction of an inch of ground before you discharge.
I can prove that the stock trackball collects dust and debris like crazy even fresh out of the bag. I disassemble and handle many a week.
I can prove that a static charged trackball with crud and/or hair stuck to it will not work as well a clean one.
I can prove that a cruddy / hair entwined roller as a result of the transfer of the aforementioned crud and/or hair from the static charged trackball will impair performance.
I can prove that dirt / moisture causes chrome to rust and pit and that something that is abrasive can scratch it. So the longevity of the rollers can be affected, depending on the nature of the crud the thousands of people, who will run their hands across a trackball in an average commercial installation, leave behind.
What other proof would you like? ;)
RandyT
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It was before 5am when I posted that nonsense. please excuse me.
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A trackballs biggest nemesis is dirt and debris. It causes them not to operate smoothly, causes premature wear on the rollers and too much of it floating around inside the case can even mess with the optics over time. Nothing attracts dust and debris like a piece of plastic with a static charge. Debris sticks to it like it's a crud magnet.
So how about other arcade controls which have a green earth wire? Spinners, analog joys, steering wheels etc...
From what you have said I don't suppose the earth would be required...
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So how about other arcade controls which have a green earth wire? Spinners, analog joys, steering wheels etc...
From what you have said I don't suppose the earth would be required...
Other controls have other electrical / mechanical configurations. Your first clue that these might be required on the devices you mentioned is the fact that they are traditionally made entirely of a highly-conductive material (steel). The screws passing through the circuit boards are in direct contact with that conductive material, which would put those devices at risk.
*edit*
It's also probably important to note that the user can come into direct contact with metal parts of the machine that go straight back to the power supply with these other controllers. An improperly grounded, or incorrectly polarized power source can be a hazard to the player. The ground wire will help to prevent injury.
*/edit*
You are mixing your apples and oranges.
RandyT
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So if I only use my cab on Mars, then I don't need an "earth" ground, correct? ;)
j/k
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So if I only use my cab on Mars, then I don't need an "earth" ground, correct? ;)
Nope, you still need one.....but now it has to be 40 million miles long.
RandyT
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So if I only use my cab on Mars, then I don't need an "earth" ground, correct? ;)
j/k
Kinda like visiting China and just eating food.
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Okay another guy who is going to be using the USB track ball from Happ. Where do we run this ground wire too? Can we daisy chain it with another one ground wire to one of the button grounds or does it have to go somewhere else by itself?
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Okay another guy who is going to be using the USB track ball from Happ. Where do we run this ground wire too? Can we daisy chain it with another one ground wire to one of the button grounds or does it have to go somewhere else by itself?
Somewhere else....route it to your earthed power supply case.
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Meaning screw it into one of the screws holding my powersupply to the ATX Case?
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Meaning screw it into one of the screws holding my powersupply to the ATX Case?
Exactly
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Sounds easy enough. Thanks guys! I will do the same for the spinner as well if it has one of the green earth ground wires!