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Oh! I was wondering about that. But how can I touch the contacts if the plug is plugged?
The difficult we do right away...
...the impossible takes slightly longer.
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Through the back of the connector where the wires go in. Just be careful not to miss the connector entirely and touch the probes to the motherboard! 
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OK I'll give it a try. Thanks.
The difficult we do right away...
...the impossible takes slightly longer.
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FYI... if your power was that far off, you'd probably have major problems. Things would flicker on/off or alternatively smoke would start coming out of the power supply or associated regulators (if it was a short causing fluctuations).
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I can read /google each one of these devices definitions / description and have some understanding how they work alone.
The question is – how do they fit together?
I have a Arduino Due with “native” USB port.
I can configure the port for USB mouse, keyboard, web cam or flash drive, no problem.
I want to write to flash drive and that is where I am not so sure how USB / SCSI LUN #0 - the only device on the USB bus - interacts with disk / file processing
I got as far as “mounting” drive at LUN #0 , but from there I am lost.
For example I can check if the “drive “ is mounted but the results are intermittent and most of the time the process just stops. And without real debugger, I am stuck. I need to better understand how it all works together to be able to follow the code manually.
Basically – does USB /SCSI LUN #0 id translates into “disk #0 “/ USB device #1? and is there a timing dependency between “working” with file / disk and USB?
Can anybody help me with understanding of how all this hardware / software interacts?
Thanks for your time.
Vaclav
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hmm here is the scenario,
in the past months my battery become dead.
Actually I am not sure if its really dead because it say it has 89% of power and charging, but if i pulled out the charger it will turn off.  then I tried to insert it to the another laptop, and the same problem occurred. I don't know if it is the battery circuit become faulty.
Then now I have a new battery and it is really good, BUT there is something I noticed, when my processor goes high or my laptop used a lot of resource in the just a matter of time, my power setting changed from charging to not charging and to charging just so quick, i dont know why it is happening, actually I already noticed it before I but a new battery, while running with my dead battery and the adapter.
why it is changing from charging to not charging, if the system used a lot of resource?
what could be the possible cause of it?
EDIT: BTW The charging light indicator of the laptop will blink if this is problem is happening.
modified 30-Nov-14 1:00am.
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The AC adapter provides a specific amount of power. Typical DC output is 19 V with max. 4.74 A (see label on your adapter) which is 90 W. This power is reduced by the efficiency of the internal power supply and battery charging device. Typical efficiencies are 80 to 90%. So you may have about 80 W of useable power from external source. When your system load is high it may require more than these 80 W. Then the additional power is drawn from the battery which is then discharging.
For that reason you should not use the system when charging an empty battery or when the battery level is low. Then the battery is not able to deliver the additional power which will be usually indicated by a low battery indicator.
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ohh there is something I notice lately on my laptop,
when it is on high performance power plan it constantly draining the battery even its say it is charging,
then if i switch it in to power saving the power percentage of the battery will become stationary,
then if i will put my to hibernation or turned it off with the adapter it will charged.
could it be my adapter is already been faulty?
ohh by the way I also tried to pull out the battery and switch on my laptop with the adapter, it will just turn on for about a 1 to 2 second then it suddenly lose power and turned off.
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Yes, it seems that your AC adapter can not provide enough power. Such adapters should be able to power a laptop without battery including start up where more power is used than during normal operation. Another indication would be long charging times.
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Thank you so much, I just buy a new adapter and everything back to normal.
BTW could you give me some light why the AC adapter lose some ampere output when the time goes? actually I am using that adapter for almost more than 2 years
thank you.
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I have no idea what happened to your adapter. Such failures are rather seldom. I would guess that a single electronic component is defective or there is a cold solder joint resulting in a lower current limiting.
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I am learning all about low level USB devices and would like to develop "stuff" ( term used is "USB controller") to connect Arduino Due "native" port to webcam.
I need to get some idea about how is webcam ( not camera ) hardware implemented.
So far all searches returned "how to connect your web cam to PC".
So there is an optical part ( no tech term yet) and the hardware which "connects" the optics to USB bus, right?
Any info / links etc on HARDWARE will be appreciated, keep in mind this is semi-embedded processor with limited resources - no Windoze API.
Thanks for your time
Cheers Vaclav
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An USB device typically contains an intelligent controller that understands commands send from the host and prepares data from it's own hardware to be send to the host. So there is some kind of protocol that allows the communication between host and device.
The handling on the host side is done by a device specific driver. This may be a common driver for well known USB device types or a specific one provided by the device manufacturer.
If you want to connect USB devices to your Arduino, you must support the corresponding protocol. I don't have used an Arduino so far, but there should be examples for common devices like storages. For other devices you must write your own protocol implementation using the information provided by the device manufacturer or searching the web (Linux drivers are often a good start).
So you might not need information on hardware but on the protocol used by a specific device.
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Jochen, thanks for the info.
Found this link <a href="http://www.usbmadesimple.co.uk/ums_links.htm">http://www.usbmadesimple.co.uk/ums_links.htm</a>[<a href="http://www.usbmadesimple.co.uk/ums_links.htm" target="_blank" title="New Window">^</a>]
Cheers
Vaclav
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Any chance somebody has a code for this display?
I had it working using serial port on AVR (Uno) , but it needs some rebuild to make it work on ARM.
Yes, I did check with the nice folks at Noritake and they don't have much for ARM.
I'll tackle it myself, but I am not that comfortable coding on registers level.
Cheers Vaclav
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Hi,
I am planning to get a retail (restaurant) POS hardware (POS Machine), only the hardware without the software.
Can anyone recommend a good brand from your experience?
Thanks,
Jassim
Technology News @ www.JassimRahma.com
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about a year ago i develop a concept of POS system ( it`s demo one ) with a food reservation system also, in details you must provide features of your system you want to determine what hardware you need.
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I have 2 hp pavilion elite hpe PCs.
One has a single monitor, and the other has dual monitors.
I'd like to add a second monitor to the first one, and a third to the other.
Is this possible? Will I need new video cards? How do I know if it's possible?
Thanks
If it's not broken, fix it until it is
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If the PC's have additional video outputs it is very likely to be possible.
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I have been studying Electrical Engineering for many years, probably about 15 years and I was curious what circuit boards you all use when creating applications for communicating across serial ports, as such USB etc... I use Vero Boards; but what are my options for substitute alternatives? I know Vero boards are not the most common or popular, so what are? I am just seeking some suggestions.
Regards,
CodingK
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When starting my career I learned to use Veroboards[^] and Perfboards[^] (those boards with single dots rather than strips). I and most of my colleagues preferred the Perfboards because Breadboards often require cutting the stripes which makes later changings more complicated than with Perfboards.
I still use Perfboards using a Wiring Pencil[^]. Because these where quite expensive 30 years ago, I made one myself for private projects at home using a drop action pencil housing with an attached spool from mother's sewing machine.
At work I'm also using Breadboards[^] for simple layouts and when testing different schematics. But final prototypes will be always wired on a Perfboards because the contacts of Breadboards wear out with time resulting in bad electrical connections.
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Jochen, thanks for the info, as I've always used Vero boards (the ones with line strips), but Perfboards seem more adaptable to work with since you don't have to drill holes in the vero strips to cut off Electrons from running the full length of that strip. This was rather helpful, thank you.
Regards,
CodingK
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I noticed this post is little stale / old , but here is my reply anyway.
I just switched to Arduino Due processor which has "native " USB port.
There are "canned" plug and play "application" for it - mouse , keyboard and two MSC "mass storage controller" - flash drive or any USB storage devices.
The main "problem" - the Due being ARM processor has minimal software written for it by "Arduino gurus" - so you are pretty much on your own.
One of the MSC is somewhat unfinished - it is missing the "access to real disk" part.
There is nothing, just lots of "talk" on Arduino web site, about USB "serial" application if you are looking for just communicating to another device using USB.
Vaclav
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