Author Topic: USB Cable Hack to Power Coin Door Lights (Read 12503 times)

djsting · « **on:** August 09, 2003, 03:56:33 pm »

I'm curious to know if anyone here has ever hacked a USB cable to power the lights in their coin door. I have been thinking, if USB can provide power to such things as PDAs to recharge them and those Antec lights from CompUSA that a couple of us have tried (including me) then why can't you cut a USB cable and splice into the + and - wires which provide this power and wire them to your coin door lights? Seems like a good solution to me. Any thoughts, comments, or instructions on doing this?

2600 · « **Reply #1 on:** August 09, 2003, 04:30:47 pm »

I'd suggest against it. If you are going to use power from the PC then use the power connectors from the power supply. This way you get more power(not that you really need it in this case), choice of +5 or +12, and don't have to worry about damaging your Motherboard.

Just be careful and check your wiring.

TalkingOctopus · « **Reply #2 on:** August 09, 2003, 05:58:34 pm »

While it may be possible to use usb, it is really easy to just use your power supply to power the coin door lights. Just clip off an unused hard drive connector, and attach the yellow wire and black wire to the light bulb.

TheTick · « **Reply #3 on:** August 09, 2003, 10:23:39 pm »

5v or 12v? If its 5v, what are you using to interface your arcade controls? The Ipac (USB and PS/2) has 5v you can tap into. Works great on my coin door's LEDs.

Howard_Casto · « **Reply #4 on:** August 09, 2003, 11:39:33 pm »

Usb can only pull 5 volts, so if you need more than that you must use the power supply.

JustMichael · « **Reply #5 on:** August 10, 2003, 06:14:13 am »

You can use USB to power coin door lights if the are leds. I would NOT recommend using USB to power incandescent lights. If you don't know what kind of lights they are then don't use USB to power them.

Spaced Invader · « **Reply #6 on:** August 10, 2003, 08:34:33 am »

As Howard said you only get 5V from you USB port, in addition the specification calls for 500ma. You could exceed that with incandescent bulbs. And although the spec. calls for 500mA I've had a motherboard that supplied less than half that. You probably CAN do it, but I'd use ths power supply. Just my 2 cents.

dendawg · « **Reply #7 on:** August 10, 2003, 04:20:08 pm »

Who needs to hack, when can buy em pre-made?

http://www.tigerdirect.com/applications/SearchTools/search.asp?keywords=usb+light

djsting · « **Reply #8 on:** August 10, 2003, 05:58:53 pm »

dendawg,

These do not work in a cabinet. The problem is that if you ever turn off your computer when you turn it back on you have to access the controll for these lights and reset them to your previous setting. As I said, I have already tried them. Pretty much sucks! I was really hoping that they would work for a cabinet.

everyone else,

Thank you all so much for the info. I will just use the computer's power supply and wire them off of that.

hulkster · « **Reply #9 on:** August 10, 2003, 08:09:20 pm »

dont mean to butt in

but i was wondering about this as well. so i can just take one of the extra power cables sticking out of my power supply in the pc in my cab....cut the end of it, and wire the yellow wire and black wire to the bulb using quick disconnects? is there a particular type of disconnect i need?

TheTick · « **Reply #10 on:** August 10, 2003, 09:04:24 pm »

I tried those Antec lights too. After reboot you have to manually turn them on again. They are also $15. Even the LEDs from Happs are cheaper than that.

Spaced Invader · « **Reply #11 on:** August 10, 2003, 10:06:38 pm »

Quote from: hulkster081 on August 10, 2003, 08:09:20 pm

dont mean to butt in but i was wondering about this as well. so i can just take one of the extra power cables sticking out of my power supply in the pc in my cab....cut the end of it, and wire the yellow wire and black wire to the bulb using quick disconnects? is there a particular type of disconnect i need?

Yes, cut it off or use a molex connector (what I did). Particular type? Eh...nope. Are you using 5v or 12v lights?

hulkster · « **Reply #12 on:** August 10, 2003, 10:11:44 pm »

well they are old lights from the cab i redid....how do i tell what kind of voltage they are? and are molex connectors the real big bulky looking plugs on the end? if so, how do i get some, and how do i wire them?

paigeoliver · « **Reply #13 on:** August 10, 2003, 11:42:41 pm »

If you are in doubt about the lights you have now, then just go to the auto parts store and get a couple of 12 volt ones. They are cheap.

I personally never really thought much about lighting up my coin door. It seems that most every game you would ever see back in the old days had the lights burnt out anyway.

hulkster · « **Reply #14 on:** August 10, 2003, 11:44:33 pm »

Quote from: paigeoliver on August 10, 2003, 11:42:41 pm

It seems that most every game you would ever see back in the old days had the lights burnt out anyway.

ha! so true!

TomJBart · « **Reply #15 on:** August 11, 2003, 12:01:49 am »

This is how I am getting power to a number of home-made devices !!

http://www.bit-tech.net/article/76/

A lot neater then connecting it directly to the power supply !!

djsting · « **Reply #16 on:** August 11, 2003, 09:48:37 am »

Tom,

Looks like a nice neat solution. Are you making these and selling them? I'm sure that several people here would be interested in them.

SirPeale · « **Reply #17 on:** August 11, 2003, 12:32:12 pm »

Where can I get a bunch of those molex connectors (for connecting drives to a PS)?

I thought maybe some Y splitters, but that would only give me one, and then I'd have two other ends that would be useless.

TomJBart · « **Reply #18 on:** August 11, 2003, 06:42:22 pm »

Quote from: djsting on August 11, 2003, 09:48:37 am

Tom,

Looks like a nice neat solution. Are you making these and selling them? I'm sure that several people here would be interested in them.

Wasn't planning to... still half way through make a couple myself and they aren't very hard !! If anyone wants help then I'm happy to give them some pointers !!

Howard_Casto · « **Reply #19 on:** August 11, 2003, 07:04:31 pm »

Looks good but I would be really scared not to label the 12 v and 5 v ports. Getting them mixed up would be a whole lot of trouble.

RandyT · « **Reply #20 on:** August 11, 2003, 08:02:13 pm »

Definitely!

The best thing to do is to make it physically impossible to plug into the wrong ports by using different style plugs.

RandyT

spidermonkey · « **Reply #21 on:** August 12, 2003, 02:37:31 am »

AUTHENTICITY PAIGE AUTHENTICITY !

Who the hell wants to replicate a beaten, used n abused machine with burnt out coindoor lights ?

Although I always admired the signature brown cigarette burns just above the player 1 and 2 buttons on ALL donkey kong style Nintendo cabs.

paigeoliver · « **Reply #22 on:** August 12, 2003, 04:57:00 am »

Quote from: spidermonkey on August 12, 2003, 02:37:31 am

AUTHENTICITY PAIGE AUTHENTICITY ! Who the hell wants to replicate a beaten, used n abused machine with burnt out coindoor lights ? Although I always admired the signature brown cigarette burns just above the player 1 and 2 buttons on ALL donkey kong style Nintendo cabs.

I think they used to ship cabinets with cigarette burns already on them.

My Artic Mini only had 700 plays on it when I got it, and mostly looked like it was fresh from the crate, except for a (admittedly small) area on the bezel that had been used as an ash tray.

Howard_Casto · « **Reply #23 on:** August 12, 2003, 03:16:05 pm »

That's why games are covered in plexi guys.

grafixmonkey · « **Reply #24 on:** August 17, 2003, 07:40:18 pm »

Everybody seems to have recommended against the USB cord lighting, so I'll play devil's advocate and say that if you get LEDs of the color of your coin reject buttons and put resistors on them, not only can you get plenty of power for them from the USB cable, but you can nab it directly from standard jumper pins on the IPAC board. Just get superbright LEDs, and check their max. current rating when you buy them. Use V=I*R, or equivalently R = V / I, to figure out what resistor you need. V is 5v, I is your current making sure you account for units like milliamps (mA) i.e. 30 mA means I is 0.03. R is in ohms. Use one resistor for each LED. Look for the flat side of the LED casing. Connect the pin on that side to ground. Connect the other pin to the resistor. Connect the other side of the resistor to the +5v pin on the ipac. You now have LEDs to light the doors with.

Note that some companies sell LEDs that fit into standard coin door lamp slots.

MrBond · « **Reply #25 on:** August 18, 2003, 09:53:05 pm »

Just a quick question on coin slot lighting:
Is it safe to power multiple (4) lights from the same set of ground and power wires? I have had it this way for a while and everything seems fine. I have a whole box in case (when) they burn out

.

Spaced Invader · « **Reply #26 on:** August 19, 2003, 09:23:00 am »

Quote from: MrBond on August 18, 2003, 09:53:05 pm

Just a quick question on coin slot lighting:
Is it safe to power multiple (4) lights from the same set of ground and power wires? I have had it this way for a while and everything seems fine. I have a whole box in case (when) they burn out .

I take it you're not pulling that from your USB port.

Shouldn't be a problem...

grafixmonkey · « **Reply #27 on:** August 20, 2003, 08:30:37 pm »

Quote from: MrBond on August 18, 2003, 09:53:05 pm

Just a quick question on coin slot lighting:
Is it safe to power multiple (4) lights from the same set of ground and power wires? I have had it this way for a while and everything seems fine. I have a whole box in case (when) they burn out .

just to be sure... no problem with incandescent lights, and no problem with LEDs which include the resistors.

You have to know exactly what you're doing to wire no-resistor LEDs in parallel. (and I mean reading I-V and temperature characteristics from their datasheets)

Oh, and I goofed earlier:

Quote

Use V=I*R, or equivalently R = V / I, to figure out what resistor you need. V is 5v, I is your current making sure you account for units like milliamps (mA) i.e. 30 mA means I is 0.03. R is in ohms.

That's wrong!! V is 5v minus the 'on-voltage' of the LED. so if your LED turns on at 2.2v, V is 2.8v.

matt888 · « **Reply #28 on:** August 28, 2003, 11:47:41 pm »

I had to laugh a bit when I stumbled across this topic

As for how nuclear bombs work...who knows, as for how to rotory engines work...who knows,...as for electrons and circuits?

I FREAKIN KNOW!

There is absolutely 100% no reason why running 2, 4, 6, 8 or however many leds around your cabinet off of a 5V or 12V USB port or any other power source on your motherboard/usb ports will do any harm PROVIDED that:

1. You KNOW what voltage is there.
2. You KNOW what the current (Amps) is available.
3. You KNOW what voltage your LED runs at.
4. You KNOW what current your LED consumes.
5. You make SURE that you have your LEDs (and each associated resistor) wired in parallel with your power supply - NOT IN SERIES!

Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

No, I'm not a smartass that read it in a book at radio shack (though you could). You could say this is my area of expertise... I did get a degree in Electrical Engineering.

Howard_Casto · « **Reply #29 on:** August 29, 2003, 12:15:38 pm »

Quote from: matt888 on August 28, 2003, 11:47:41 pm

I had to laugh a bit when I stumbled across this topic As for how nuclear bombs work...who knows, as for how to rotory engines work...who knows,...as for electrons and circuits?

I FREAKIN KNOW!

There is absolutely 100% no reason why running 2, 4, 6, 8 or however many leds around your cabinet off of a 5V or 12V USB port or any other power source on your motherboard/usb ports will do any harm PROVIDED that:

1. You KNOW what voltage is there.
2. You KNOW what the current (Amps) is available.
3. You KNOW what voltage your LED runs at.
4. You KNOW what current your LED consumes.
5. You make SURE that you have your LEDs (and each associated resistor) wired in parallel with your power supply - NOT IN SERIES!

Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

No, I'm not a smartass that read it in a book at radio shack (though you could). You could say this is my area of expertise... I did get a degree in Electrical Engineering.

Apparently you don't have your A+ certification though smart guy. (I do) USB ports max out at 5 volts, that is why we said you can't run a 12v light off of it. Duh! There are only three places you can get a clean 12v off of a computer. Through a hd accessory connector(yellow wire) or on two points (or a few more on the old at's) at the main powersupply connector to the board, which isn't viable as monkeying with the flow of juice can cause "smart" motherboards not to boot and/or can permenantly harm your system.

As for the other guys squabbling over running LEDS (big difference) then yeah, you can pretty much run anything given it'll drive on 5v and you wire in parallel, as you said.

The moral of this story is: Being an electrician doesn't mean squat if you aren't familiar with the device you are working on. So don't mock people unless you truely have a mastery of the topic at hand. However, your advice regarding wiring should be very helpful to people and I'm sure they will appreciate it.

Thank you for playing! (copyright planetjay 1984)

RandyT · « **Reply #30 on:** August 29, 2003, 12:44:20 pm »

Quote from: grafixmonkey on August 20, 2003, 08:30:37 pm

just to be sure... no problem with incandescent lights, and no problem with LEDs which include the resistors.

Err...Admittedly, I don't know how much current an average incandescent light will draw, but I do believe it's a heck of a lot more than LEDS. Incandescent bulbs put off heat, and that heat isn't free. That's dissipation of current.

I for one would never try to power a conventional bulb from any port on the computer. Straight from the power supply, probably ok, but not from USB or PS/2 ports.

RandyT

Oh, and HC.....Aside from the fact that there are no 12v USB ports

, everything Matt888 said is "spot on". After following his first statement, one would realize that anyhow.

Howard_Casto · « **Reply #31 on:** August 29, 2003, 01:32:08 pm »

I know randy, but making such a fatal screwup isn't allowed when you are flaming people for not knowing what they are talking about.

Incandescent lights will NOT work properly under usb power, they pull 12v or more and a buttload more amperage, that was my point. So you are absolutely correct even though you just elaborated on what I just said.

RandyT · « **Reply #32 on:** August 29, 2003, 02:53:02 pm »

Quote from: Howard_Casto on August 29, 2003, 01:32:08 pm

I know randy, but making such a fatal screwup isn't allowed when you are flaming people for not knowing what they are talking about.

Incandescent lights will NOT work properly under usb power, they pull 12v or more and a buttload more amperage, that was my point. So you are absolutely correct even though you just elaborated on what I just said.

Ok, now I am going to have to take exception

.

First off, Matt888 was a little brazen in the style of his post, but I couldn't find a "flame" in it.

Secondly, his statement about power and PC ports was more of a general one than you interpreted it as. He didn't actually state that USB was 12v, rather that (implied) if a 12v USB port existed, it wouldn't matter as those same principles would stiill hold true. A bit confusing to someone who didn't know otherwise? Perhaps, but a simple clarification that "12v USB ports do not exist and only 5v can be obtained" is really all that was necessary there without "tossing the baby out with the bathwater". He claimed to know "electrons and circuits", which he clearly does, not "PC architecture".

And lastly, unless you made some other post in this thread regarding the use of incandescent lights powered by PC ports, I did not merely "elaborate" on your statements. Please don't minimize or take credit for my contributions.

RandyT

Howard_Casto · « **Reply #33 on:** August 29, 2003, 03:34:12 pm »

Randy I don't even think I have to justify my last posts. You don't seem to be able to understand what you are reading. I strongly suggest you go back and re-read before you jump all over me and get yourself involved in a discussion that wasn't directed towards you.

I mean dude one of your arguments against my last post was that the guy knows electronics and not pcs. That was the point of me making the post, to point out that he doesn't know pcs and thus can't accurately respond. Why else would I point that out?

Quite frankly I was defending virtually everyone in this thread reagarding some rather rude and arrogant statments directed towards them while you are singling out me for no apparent reason other than to prove that I am wrong(which I'm not btw). So what exactly is your point?

hyiu · « **Reply #34 on:** August 29, 2003, 04:11:30 pm »

Sorry have to jump in.....
I have re-read this whole thread from the beginning...

and come on.. HC... that guy is not flaming...

HC, I really appreciate your knowledge..... and your "correctness" of every single details of all your posts...

but can you please stop stepping on everyone whenever you see a chance ??.... Seems to me you've been in a bad mood recently......

is it that you're not able to break your high score in Ms Pacman ??

RandyT · « **Reply #35 on:** August 29, 2003, 06:26:58 pm »

Quote from: Howard_Casto on August 29, 2003, 03:34:12 pm

Randy I don't even think I have to justify my last posts. You don't seem to be able to understand what you are reading. I strongly suggest you go back and re-read before you jump all over me and get yourself involved in a discussion that wasn't directed towards you.

Howard,

Your reply to me also regarded something that "wasn't directed towards you", rather it was Grafixmonkey whom I quoted. He attempted to summarize, and did so incorrectly. You made an incorrect assumption that that portion of my post was directed toward you.

Quote

I mean dude one of your arguments against my last post was that the guy knows electronics and not pcs. That was the point of me making the post, to point out that he doesn't know pcs and thus can't accurately respond. Why else would I point that out?

Once again, it's not what, but how. There was no "flame" there but you felt the need to denigrate him anyway, purportedly for his lack of knowledge on the subject. What you fail to realize, is that when you made this post:

Usb can only pull 5 volts, so if you need more than that you must use the power supply.

you also erred. While what you wrote isn't exactly incorrect, it is incomplete and dangerous in the context it was presented in. You made this statement in the context of the original post, in which djsting was referring to powering "coin door lights". Realizing that your statement was incomplete, JustMichael and SpacedInvader followed up your post with the real reason as to why "coin door lights" should not be driven from the USB port.

And while most coin door lights are 12v, one could also replace them with lower voltage bulbs. Had no-one come behind you with the "rest of the picture", it's quite possible that this would have happend and the original poster would have damaged their computer.

But they did, so all is well......and they didn't belittle you in the process (but they could have).

Quote

Quite frankly I was defending virtually everyone in this thread reagarding some rather rude and arrogant statments directed towards them while you are singling out me for no apparent reason other than to prove that I am wrong(which I'm not btw). So what exactly is your point?

My point is what I wrote above, and I wouldn't even have done that had you not insisted that I "re-read the thread", which I did, and understand very well, thank you.

Most people here seem to be pretty "grown-up" and able to defend themselves. I'm sure if they felt trodden upon your "services" wouldn't be necessary. And from my experiences, Howard, I'm thinking most would rather be defended from, than by you.

RandyT

Howard_Casto · « **Reply #36 on:** August 29, 2003, 08:06:37 pm »

I generally don't say this randy but you aren't making any sense at all. You can't power coin door lights with usb because coin door lights need more than 5volts and usb can only give you that much. What I said was not only perfectly and exactly correct, but simple and filtered down to a simple sentence so that anyone, even you could understand it. Use some common sense man. In the history of coin doors only two or 3 types of bulbs have been used. 6volts, 16 volts and 12 volts. All of these are more than 5 (can you add?). Since these are the only lights (at least commonly, there may be an oddball somewhere) ever used on coin doors these are "coin door lights". Anything else isn't a coin door light. The others addressed using leds, but the topic went back to using traditional bulbs, and thus I responded, with my short, but to the point post. I don't know why I would need to explain more, but the others did to ease his mind. Never the less doing what I say generally will never steer you wrong.

"Most people here seem to be pretty "grown-up" and able to defend themselves. I'm sure if they felt trodden upon your "services" wouldn't be necessary. And from my experiences, Howard, I'm thinking most would rather be defended from, than by you."

If that is true then why are you doing it now? Quite frankly this thread is none of your business. You didn't add any info, but merely commented on my conduct. I may have expressed my distain, but I also corrected the info. In other words I was helpful. You on the other hand haven't offered any info other than a comment on incandescent bulbs, which btw are virtually the same (power wise) as regular bulbs and is why I said I had already commented on it. I guess I had to spell it out for you.

I'm sure in your own mind you thought you were doing right, but you merely "fanned the flames" Respectfully, I was in this thread before it got heated, and I felt insulted by his comments, so I had a right to respond. You weren't and thus you don't.

Thank you for your insight, but please drop it. If you have a problem pm me, don't take it out here.

RandyT · « **Reply #37 on:** August 29, 2003, 09:12:09 pm »

Quote from: Howard_Casto on August 29, 2003, 08:06:37 pm

I generally don't say this randy but you aren't making any sense at all.

Actually, you say this quite often and not just to me

Quote

You can't power coin door lights with usb because coin door lights need more than 5volts and usb can only give you that much. What I said was not only perfectly and exactly correct, but simple and filtered down to a simple sentence so that anyone, even you could understand it.

Howard, a 6-volt lamp will light fine with 5 volts. You WILL kill your USB port if you try to get the power from there. It won't be the lack of voltage that does it, but the current drawn by the bulb. Can you understand that?

Quote

...{snip} I don't know why I would need to explain more, but the others did to ease his mind.

Quit deluding yourself, it's getting old.

Quote

Never the less doing what I say generally will never steer you wrong.

Yeah, I still remember the time you said there were no admin buttons inside arcade machines. But you are right, since I knew better, you didn't steer me wrong.

Quote

If that is true then why are you doing it now? Quite frankly this thread is none of your business.

Quote

You didn't add any info, but merely commented on my conduct. I may have expressed my distain, but I also corrected the info. In other words I was helpful.

Yeah, I'll bet everyone else sees it that way too. See the part about delusion above.

Quote

You on the other hand haven't offered any info other than a comment on incandescen
t bulbs, which btw are virtually the same (power wise) as regular bulbs and is why I said I had already commented on it. I guess I had to spell it out for you.

In case you missed it, Howard, as I said, those comments were for Grafixmonkey who summarized the thread incorrectly. You were the one that hammered yourself into that one.

Quote

I'm sure in your own mind you thought you were doing right, but you merely "fanned the flames"

There were no flames in this thread until you gurgitated them. Oh, and seeing that you are sure about what is in my "own mind", what am I thinking now?

Quote

Respectfully, I was in this thread before it got heated, and I felt insulted by his comments, so I had a right to respond. You weren't and thus you don't.

The word "respectfully" isn't usually used, right after you insult somebody, so I don't know how to interpret that.

The part about me not having the "right" to respond and somehow you deciding that, just deserves another

Quote

Thank you for your insight, but please drop it. If you have a problem pm me, don't take it out here.

Ahh, a sensible end to an insulting post.....how do you do it?

Ok, I'm bored. Have at me (PM, if you wish)

Oh, and just to keep this thread on topic (you can look away now Howard, if you don't feel I have the right to post

):

"Normal" bulbs as referred to in this thread and as used in garden variety coin-doors are incandescent.

Incandescent bulbs can be purchased in any number of sizes and or voltages.

You don't have to give an incandesent bulb *exactly* the rated voltage. A 6-volt will light on 5-volts. Might be a little dimmer, but you probably won't notice much. Just don't go higher than rated or it will be brighter but only for a very short time

. Another bonus is that a bulb rated for 6volts will probably last longer at 5volts. A candle that burns half as bright, burns twice as long and all that rot.

If you want to use a certain type or voltage of bulb, as long as it fits into the hole behind the reject button and you can find a socket for it (or it fits in the one you have), just replace the one that is in there with what you want. Just Make sure you give it the voltage/current it needs and don't power it from the PS/2 or USB port.

And when you finally come to your senses:

Hot melt a fifty-cent 10,000mcd white LED into the hole, hook up the appropriate resistor, give it 5v from just about anywhere you care to (following what Matt888 said) and fugheddaboutit. It will last for over 10 years of constant on time.

RandyT

matt888 · « **Reply #38 on:** August 29, 2003, 10:18:01 pm »

Howard Casto-

You're right, I didn't get an "A+" in EE.....for some reason none of the A's in college had a "-" either, but I move on...

I found your reply to be a good laugh again at best. I didn't realize that you would run around the house cheering "Matt888 thinks there's 12V USB ports!" I was strictly coming from a "How do I decide what to do with my LED and voltage/current available to be safe and get the job done standpoint."

As for computers... there's a little bit of schooling there too as that was my minor (Computer Science). But, you can laugh at me, I did get a few "B's" in that course work!

Everyone has something to offer to this community. Whether it's helping others in general or even trying to find an undotted "i" like you HC. J/K!

Back to electrons eh?!

Oh another thing... please don't refer to me as an electrician. That's kind of like saying an airline pilot is a radio controlled airplane operator. There's quite a bit of difference in the training/education.

Cheers!

Salellron · « **Reply #39 on:** August 29, 2003, 10:40:54 pm »

I'm not one to post much (unless I feel I can help someone..

), but damn, me thinks HC is a little 'stuck' on himself.

Sal

grafixmonkey · « **Reply #40 on:** August 31, 2003, 06:24:40 am »

Quote from: matt888 on August 28, 2003, 11:47:41 pm

I had to laugh a bit when I stumbled across this topic As for how nuclear bombs work...who knows, as for how to rotory engines work...who knows,...as for electrons and circuits?

I FREAKIN KNOW!

There is absolutely 100% no reason why running 2, 4, 6, 8 or however many leds around your cabinet off of a 5V or 12V USB port or any other power source on your motherboard/usb ports will do any harm PROVIDED that:

1. You KNOW what voltage is there.
2. You KNOW what the current (Amps) is available.
3. You KNOW what voltage your LED runs at.
4. You KNOW what current your LED consumes.
5. You make SURE that you have your LEDs (and each associated resistor) wired in parallel with your power supply - NOT IN SERIES!

Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

No, I'm not a smartass that read it in a book at radio shack (though you could). You could say this is my area of expertise... I did get a degree in Electrical Engineering.

you know what, dude, you just might not be the only one here in electrical engineering. I took all the way through processor design and transmission lines at the U of I before I opted to use it as a course sequence for a math degree instead, and go into computer graphics. So maybe check and see if you really read something right before ya break out the cannons, huh?

Quote

Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

No. That's wrong. You drive an LED with a current. If you look at a datasheet for one, you'll see that in its operation range dV is nearly constant for any dI that doesn't burn the thing out. You must provide the correct limitation of current to the LED to keep it from sucking up too much. It doesn't just "consume its 20mA" and neither is it likely to if you drive it directly with a voltage source. I calculated the margin of error for not burning out a voltage driven LED from one bin in Fairchild to be in the hundredths of volts, assuming the device would draw current exactly according to its datasheet.
EDIT: It's even more wrong than I thought, because if the LEDs are in series like they should be if you connect them to 12v, you don't add up their currents. You calculate the total power consumption, sigma[V*I].

Also, I've done current measurements with IPB and coin door lamps from Happ, and they consume 160mA at 12V. If a USB port could power this, you could run three 160mA devices before being in the red line. Granted you can't plug a 12V lamp into a USB power source because there isn't a 12v pin, but if the 5 or 6v lamps are anything remotely similar, they should work too. I also know of flashlight bulbs that sure as heck aren't drawing 160mA, because they're running on batteries, and they get a bright bulb out of as little as 3v.

And dude with the 8's in his name:
I know how hard a EE degree is to get. So congrats on having one. However, I also know that other people here don't have one, so you laughing at people for asking questions about ground loops and power consumption is kind of like me lording it over on you for not knowing how to draw a straight line between points in the Poincare model of hyperbolic space, or what the heck I mean when I say that having under-weighted points in a subdivision skinned skeletal system will result in improper results when the root joint translates.

Besides, I knew a lot of EE people in the U of I. I lived for three years in a dorm where 70 percent of residents were EE. They're one of the best schools for that, and I was frequently helping grad students to actually build their projects, because while they knew a heck of a lot about theory, they knew nothing when it came down to the actual devices. So don't tell me you know everything just because you have the degree.

grafixmonkey · « **Reply #41 on:** August 31, 2003, 06:48:34 am »

Quote from: Howard_Casto on August 29, 2003, 01:32:08 pm

I know randy, but making such a fatal screwup isn't allowed when you are flaming people for not knowing what they are talking about.

Incandescent lights will NOT work properly under usb power, they pull 12v or more and a buttload more amperage, that was my point. So you are absolutely correct even though you just elaborated on what I just said.

They don't "pull 12v." The light will not force the port to 12v, neither will it draw more current than it would if it were connected to 12v. A 12v lamp connected to a 5v source would operate dimmer, with less current and less power consumption. And, as I stated in my other post as well as on another thread (possibly this one but I don't feel like looking) the incandescent lamps I've tested draw well under the power supply limit for a USB port. There are also lamps that do operate at the voltages a USB port can provide. Examples are here:
http://www.happcontrols.com/lighting/91003700.htm
and here:
http://www.happcontrols.com/lighting/91204400.htm
ideal lamp numbers being #'s 44, 47, 86, 259, 447, and 555, all of which should operate quite nicely on 5V. Happ does not list the power requirements for those lamps, so I can't guess how many would be safe to plug in without testing, but it's certain that at least one would work and be perfectly safe for the port.

Carsten Carlos · « **Reply #42 on:** August 31, 2003, 08:35:16 am »

Don't wanna jump to much into this discussion, but regarding the USB-specifications, you can only drive 100mA from each port until the driver of your USB-device (that you won't have at this hack) asks for ok to demand 500mA.

Though it would work on many motherboards anyway, this is not the right way to do it.
Leave the USB where it is, and get +5V/+12V from your powersupply. You never know if you need more current anyway in future.

matt888 · « **Reply #43 on:** August 31, 2003, 01:18:10 pm »

Quote

Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

Quote

No. That's wrong. You drive an LED with a current. If you look at a datasheet for one, you'll see that in its operation range dV is nearly constant for any dI that doesn't burn the thing out. You must provide the correct limitation of current to the LED to keep it from sucking up too much. It doesn't just "consume its 20mA" and neither is it likely to if you drive it directly with a voltage source. I calculated the margin of error for not burning out a voltage driven LED from one bin in Fairchild to be in the hundredths of volts, assuming the device would draw current exactly according to its datasheet.

Hmmm... I am NOT wrong! It will consume it's current rating. End of story. You are also misleading others! Higher than it's tolerance VOLTAGE blows an LED... NOT CURRENT. You must provide the VOLTAGE limitation to the LED! ie - if you want an LED that operates at 20mA/2V to run off a 5V USB port, you must DROP the voltage that you don't need across a resistor. So, since V=IR, you have 3V(the additional voltage you DON'T want across the LED)=.020A x R. Find R, so 150 ohm resistor is what you need to buy in this case. Now there are some fluctuations in tolerances, but you will not find them to be an issue in this "light up my coin door case."

Quote

EDIT: It's even more wrong than I thought, because if the LEDs are in series like they should be if you connect them to 12v, you don't add up their currents. You calculate the total power consumption, sigma[V*I.]

AGREED

Quote

Also, I've done current measurements with IPB and coin door lamps from Happ, and they consume 160mA at 12V. If a USB port could power this, you could run three 160mA devices before being in the red line. Granted you can't plug a 12V lamp into a USB power source because there isn't a 12v pin, but if the 5 or 6v lamps are anything remotely similar, they should work too. I also know of flashlight bulbs that sure as heck aren't drawing 160mA, because they're running on batteries, and they get a bright bulb out of as little as 3v.

AGREED

Quote

And dude with the 8's in his name:
I know how hard a EE degree is to get. So congrats on having one. However, I also know that other people here don't have one, so you laughing at people for asking questions about ground loops and power consumption is kind of like me lording it over on you for not knowing how to draw a straight line between points in the Poincare model of hyperbolic space, or what the heck I mean when I say that having under-weighted points in a subdivision skinned skeletal system will result in improper results when the root joint translates.

Seems as though you have read the original post like HC. It was never meant to disrespect anyone, and was more of an entertaining way of posting on the dry material of electricity. I apologize to those of you that have helped EE's get their degrees

- That's good stuff too!

Quote

Besides, I knew a lot of EE people in the U of I. I lived for three years in a dorm where 70 percent of residents were EE. They're one of the best schools for that, and I was frequently helping grad students to actually build their projects, because while they knew a heck of a lot about theory, they knew nothing when it came down to the actual devices. So don't tell me you know everything just because you have the degree.

As for the Poincare of hyperbolic space, sounds like a very exciting and stimulating topic also. Perhaps we can get together sometime and discuss this...along with my current task that I get paid for: Determining the optimal OBSA (Off Bore Sight Angle) that the Aim-9X Sidewinder needs to achieve to beat the 4th generation MIGs after it and our F-15C hit the "merge" and begin the single or double circle fight. See, I don't exactly fall into the "EE's have theory down, but no practicality" pot. As the lead test engineer of the Aim-9x program at Nellis AFB, I have quite a bit of hands on action and real world theory tested also. Sometimes good, sometimes bad, but the F-15C Eagle is a can of whoopass thanks to more than theory.

Uh oh, here comes a post from someone that designed the space shuttle

Seems like alot of these posts get out of control. This community/forum is an awesome place and I would not have 2 amazing MAME machines right now if it wasn't for the large collection of experience and knowledge around here. My genuine thanks goes out to everyone ... including Grafix and HC! Can't we all just get along?

grafixmonkey · « **Reply #44 on:** August 31, 2003, 08:40:33 pm »

Quote from: matt888 on August 31, 2003, 01:18:10 pm

Quote
Bottom line is each LED will consume its required current (say 20mA or .020A). When you add up all of your LEDs, it better NOT be more than what's available current wise from that power supply(or USB port). If it is...you will be F%$&d!

Quote
No. That's wrong. You drive an LED with a current. If you look at a datasheet for one, you'll see that in its operation range dV is nearly constant for any dI that doesn't burn the thing out. You must provide the correct limitation of current to the LED to keep it from sucking up too much. It doesn't just "consume its 20mA" and neither is it likely to if you drive it directly with a voltage source. I calculated the margin of error for not burning out a voltage driven LED from one bin in Fairchild to be in the hundredths of volts, assuming the device would draw current exactly according to its datasheet.

Hmmm... I am NOT wrong! It will consume it's current rating. End of story. You are also misleading others! Higher than it's tolerance VOLTAGE blows an LED... NOT CURRENT. You must provide the VOLTAGE limitation to the LED! ie - if you want an LED that operates at 20mA/2V to run off a 5V USB port, you must DROP the voltage that you don't need across a resistor. So, since V=IR, you have 3V(the additional voltage you DON'T want across the LED)=.020A x R. Find R, so 150 ohm resistor is what you need to buy in this case. Now there are some fluctuations in tolerances, but you will not find them to be an issue in this "light up my coin door case."

In which case, what you are doing is inserting an ohmic device that gives you control over the current (which the LED does not), and adjusting the ohmic device until the current is correct. It's a way of converting a supply of a specific voltage supply into a supply of a specific current. I've attached a VI curve from an LED datasheet at Fairchild. http://www.fairchildsemi.com I highlighted the operating range of the LED yellow, and the V and I operating ranges in red on the axes. If you want to "give this thing 1.75v" and use its VI curve to drive it, you'd better be sure your power supply doesn't vary by more than 0.02 volts. And if you measure your PC power supply, I guarantee you will not see exactly 5.00v on your meter.

Another approach: if what you say is correct, then I would be able to use a Zener diode of exactly 3.25v, hook it up in series with this LED, and it would work. But I'm sure you'll agree that it won't, because now that you've removed the ohmic device that lets you solve for current, if your power supply does vary by a +0.1 volt, your LED will burn out, and if it varies by -0.1v it will be dim.

Quote

Seems as though you have read the original post like HC. It was never meant to disrespect anyone, and was more of an entertaining way of posting on the dry material of electricity. I apologize to those of you that have helped EE's get their degrees - That's good stuff too!

I guess it's an effect of seeing the replies on my way up to the post. LEDs have been a frequent topic of argument on the board, since they are difficult to properly drive unless you know the theory. There was a guy insisting that it was just fine to put a bunch of resistorless LEDs in parallel, with one limiting resistor for all of them, and was selling devices build this way. While he may have found a part number with a shallower VI curve that allows this, it's asking for trouble if you try it with any old LED, or a mixed batch. There were some other people too which were taking LEDs out of little LED flashlights, attaching them to a power source of precisely the same voltage as their batteries, and wondering why the things just instantly burnt out. The reason they burnt out is exactly what I'm talking about with this new LED discussion.

Quote

As for the Poincare of hyperbolic space, sounds like a very exciting and stimulating topic also. Perhaps we can get together sometime and discuss this...

Picture two people starting out within arm's reach of each other, facing perfectly parallel to each other, and walking straight forward (perfectly straight!) at exactly the same speed for exactly the same time. Now one of them turns exactly 90 degrees to face the other person. He can see the other person in front of him, 100 feet away. That's hyperbolic space. Weird huh?

Quote

My genuine thanks goes out to everyone ... including Grafix and HC! Can't we all just get along?

ohhhh, all right... group hug!!!

JustMichael · « **Reply #45 on:** September 01, 2003, 04:38:40 am »

Personally the easiest way for most people to do this is to wire a resistor inline with each led to limit its current.
First, find out what the maximum current is that the led can handle. (example 20ma [same as .02A])
Second, how much voltage is available. (example 5V)
Third, figure out how much resistance is needed to keep the led from getting too much current (example Resistance = Voltage / Current)
Resistance = 5 / .02
Resistance = 250 ohms

This simply gives is the smallest size resistor (or series of resistors) that you want to use inline with the led. Larger resistors than the value found will result in a dimmer led.

grafixmonkey · « **Reply #46 on:** September 01, 2003, 04:52:11 am »

yes... the way you use the LED ends up being the same in almost all cases, we're just debating a rather technical point about it - that being that you must arrange a circuit such that it provides the proper current to an LED, not one that attempts to provide the proper voltage to one. (although if you can control the voltage supply to the tenth or hundredth of volts, accurately, you can do the latter.)

matt888 · « **Reply #47 on:** September 01, 2003, 01:26:09 pm »

Just Michael - yes!

Grafix- Do I get to post an LED spec graph with a MUCH steeper current curve?! J/K Also, there's no need to wonder if the voltage source is substantially off of say...a 5V USB port. That's why man created a digital multimeter. Now you've got THE VOLTAGE available and your resistance pinned down and the guessing only lies with how well the LED meets its tolerances/specs.

I'm off to play MK2... anyone else find it amusing in revision 2.1 to do the Babalities multiple times and cause the game to go in cardiac arrest?

grafixmonkey · « **Reply #48 on:** September 01, 2003, 03:34:12 pm »

oh well... I don't completely agree but you know what's going on and I'm sure everybody else stopped reading a loooong time ago.


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