Tuesday, April 30, 2013

12V Car Charger For ASUS Eee Notebook

The ASUS Eee is a fantastic ultra-portable notebook with almost everything required for geeks (and nothing that isn’t). Plus it features fantastic build quality and is very well priced. If you live in New Zealand you can get them from DSE; at the time of writing they are the exclusive supplier. I worked out it’s the same cost as importing one once you include all the duties and tax, plus you get the advantage of a proper NZ-style mains charger. Anyway, being so small I thought it would be nice to be able to carry this around in the car. Unfortunately I couldn’t find a car charger available anywhere at the time so I decided to tackle the problem myself. As a bonus this provides an opportunity for an external high-capacity battery.

Commercial Equivalent:
I thought at this stage it would be worth noting that a commercial car charger is now available for less than it cost me to build this from Expansys and is available in most countries (select your location on their site). It outputs 9.5v from 10-18v in at up to 2.5A. I’d actually recommend it over the design here is it seems to perform better at lower voltages (that one works down to 10V). However I have kept this page up as a reference for those who enjoy tinkering.

The charger included with the Eee is rated at 9.5v, 2.315A. There isn’t a fixed voltage regulator available for this exact voltage, so the circuit needed to be designed around an adjustable regulator. I decided to design the charger around the LM2576 “Simple Switcher” IC from National Semiconductor. There are tons of ICs like this available, many of which are a bit more efficient, however I selected this one because it is readily available and relatively cheap. It also has a lower drop-out voltage (~2V) than many other chips I looked at which is important when powering the device from a car or 12v SLA battery.

This circuit could have used a standard three pin regulator IC such as the LM317, however most types require an external transistor when handling so much current and not to mention the fact that they are very inefficient; they draw the same amount of current from the input as the load and the difference in power is dissipated as heat. The main problem with using the LM2576 is the fact it needs quite a large inductor due to its somewhat low switching frequency. The inductor I used is made by Pulse Engineering, part number PE92108KNL. I’d prefer a smaller one, however I couldn’t find one capable of supplying the required current that I could purchase in single units. Besides the PE92108KNL is apparently designed specifically to work with the LM257x series.

The circuit also includes a low voltage cut-out based on a 9.1v Zener diode and BC337 transistor that will shut down the regulator if the input voltage is below 11.5V. This prevents unstable operation of the regulator at lower input voltages, and also helps prevent accidental flattening of the supply battery. Substituting this transistor for similar type may affect the cut-out voltage; the Vbe of the transistor should be 1.2v.All of the components used should be pretty readily available in most areas. I got everything from Farnell. Jaycar also sells everything except the inductor. Make sure you specify high temperature, low ESR capacitors as these help result in more stable operation and better efficiency of the charger.

Unfortunately the end result is a charger that is slightly bulkier than I would really like. I attempted to fit this inside an old mobile phone charger case so the whole thing could hang out of the cigarette lighter, however I ran into trouble making the circuit stable enough and dissipating all the heat. Due to the high current involved compared to a mobile phone charger the components are much bulkier so it’s pretty tricky to get all to fit! If I do get it finished I’ll add an update.

Parts List:
  • 2x 10k resistor (R1 & R4)
  • 2x 22k resistor (R2 & R3)
  • 1x 1.5k resistor (R5)
  • 1x 120μF 25v electrolytic capacitor (C1)
  • 1x 2200μF 16v electrolytic capacitor (C2)
  • 1x 1N5822 Schottky diode (or equivalent)
  • 1x 9.1v 0.5W Zener diode
  • 1x BC337 NPN transistor
  • 1x LM2576T-ADJ IC
  • 1x 100uH, 3A inductor (e.g. Pulse PE92108KNL)
  • 25°C/W or better minature heatsink (e.g. Thermalloy 6073)
  • Cigarette lighter plug with 3A fuse and 2.1mm DC plug (e.g. DSE P1692)
  • 2.1mm DC chassis mount socket
  • 1.7mm x 4.75mm (ID x OD) DC plug and cable
  • Small plastic enclosure
Building It:
Make yourself a PCB using the template below (600dpi). I simply laser print (or photocopy) the design onto OHP transparency sheet and then transfer the toner onto a blank PCB using a standard clothes iron. Any missing spots can be touched up with a permanent marker before etching. This is quick, usually results in pretty tidy boards and hardly costs a thing. There is a tutorial on a variation of this method at http://max8888.orcon.net.nz/pcbs.htm.
Install the components on the PCB and triple check the layout before soldering. It is much easier to start with the low profile components such as resistors and diodes, then install the larger components after-wards. Don’t forget the wire link; this is shows as a red line on the layout guide above. Remember to smear a small amount of heatsink compound on the regulator tab before mounting the heatsink.

For a case I used a small plastic enclosure from DSE, part H2840, as it was all the local store had in stock that was remotely suitable. The PCB is designed to fit into this particular case, however any small box should be suitable. If you have a dead laptop charger lying about it might be worth ripping the guts out of that and salvaging the case. If your enclosure is different you may need to modify the design to suit, so I have provided the schematic and PCB design files for download. They were created using Eagle. The Eee uses a standard 1.7mm DC power connector with a positive tip.
Connect the circuit to a 12v supply. If you use a car or lead acid battery ensure you have a 3A fuse fitted in line with the circuit before connecting it, just in case. Use your multimeter to check that the circuit outputs about 9.45v with no load. Connect a 12V, 21W lamp (e.g. old brake lamp from a car) or similar load across the output and check that the voltage doesn’t vary much. You should now be able to connect your Eee. The circuit design should be good for up to 2.5A, so there is plenty of margin for the Eee to fully function and charge its own battery off this supply.

SLA Battery Carry-bag:
Jaycar have a really cool carry bag with a shoulder strap designed to perfectly fit a 12v 7AH sealed lead acid battery. The bag features a fused cigarette lighter socket and is the perfect compliment to this charger. It works well with the Eee and provides hours of extra use. The shoulder strap means it’s not too bothersome to carry about and the charger circuit itself zips up neatly inside the bag. The under-voltage cut-off means the battery will never run completely flat, and the Eee will simply cut over to its internal battery once the SLA runs out. I got my SLA battery from Rexel as they are much cheaper (approx NZ$18 including GST last time I bought one) and they don’t sit as long on the shelf as many other suppliers.

This circuit is intended for people who have had experience in constructing electronic projects before. The circuit design and build process are provided simply as a reference for other people to use and I take no responsibility for how they are used. If you proceed with building and/or using this design you do so entirely at your own risk. You are free to use the content on this page as you wish, however I do ask that you include a link or reference back to this page if you distribute or publish any of the content to others. 

Source: Marlborough Wi-Fi
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Wednesday, April 10, 2013

Boost PC Speed

If you acquire a brand new computer, it often needs to be the top performing pc within the marketplace. You do not have to acquire the top-of-the line pc, although, all you will need should be to verify the appropriate specs that unique pc has. Whenever you verify your chosen computer’s specifications, pick one which is best for the particular tasks youd be making use of it for. Also, it would be a very good idea to verify the price tag also. You will get the top bargain out of a brand new computer once you get a computer using the optimum specifications necessary for the specific tasks at the lowest value available.

Over a long period of time, even so, your new pc will develop old. Because the quantity of years your computer is continuously made use of, it is going to sooner or later carry out slower than usual. This really is simply because continual utilization of your pc will call for it to accumulate additional data which means much more memory is utilized up that will take your computer much more time to retrieve a certain data. this in turn stresses your computer’s system. Youll eventually practical experience sluggishness, lags, errors, or at worst crashes. Aside from accumulated data, malicious software program can also influence your pc’s performance. Old pcs ultimately turn out to be prone to these type of software specifically with continual access to the internet where these type of software package breed and get distributed.   

If you locate your computer to be experiencing these challenges, then you do not must panic, there are lots of ways to solve them and make computer faster. It is important for even the typical user to know simple ways to make pc faster in performance. In truth, you do not need to be a computer expert to complete these very simple strategies; all you require would be the suitable information along with the proper tool. The simplest way to solve any of these common computer problems is by utilizing a utility software program, like a maintenance program or perhaps a cleaning software package.
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Monday, April 8, 2013

Windows 8 Tools

Updated versions would be the ones that people today anticipate now. Now, folks would constantly wait for your newest versions in the latest “it” factors. In today’s trend, you would not have to wait too extended just for your newest version since the time span is quite brief when they release versions. The new versions that theyve include things like the newest offering that theyve for their items. Though these additions or changes may perhaps just appear very small, still many people choose to have the most recent version, whether it be gadgets, applications, games or maybe programs.

For the computer, you had been usually utilised to putting in or making use of the Windows operating process. Properly, it truly is one of the most user-friendly software program for any large amount of folks mainly because most of us had been seriously employed to computers with this type of operating system. For the longest time that it reigned inside the market place, it has also updated its versions to become in a position to cope up together with the fast-paced life and also the continuously shifting preferences in the industry. Probably the most updated version now will be the windows 8. Listed below are several of the best free Windows 8 programs which you can attempt:

VLC media player - with Windows 8 you will find restrictions to playing particular sort of media or some media files are usually not getting supported. Fantastic factor you could download this system which can read and play all media formats. This is the newest version in the program that could defend your windows 8 from viruses that should corrupt your computers. Windows 7 USB/DVD Download Tool - usually do not be fooled by the name due to the fact by means of this you are going to be oriented on tips on how to install the Windows 8 inside your computer systems.

For you personally to test regardless of whether youre comfy or compatible using the new Windows version, download and install the free Windows 8 in your computer and expertise what it offers you.
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Sunday, April 7, 2013

The IE 10 On Windows 7

The most recent version of Microsofts Internet browser is now out there to the vast audience connecting to the World wide web on private computer systems running on the ie 10 windows 7 operating process. The redesigned browser, Internet Explorer 10, produced its debut final month when Microsoft released Windows 8, which tends to make dramatic adjustments to an operating program thats been powering PCs for decades.

Internet Explorer 10 initially is becoming introduced Tuesday to Windows 7 customers in a "preview," or test, mode. The new browser isnt compatible with XP, Vista and any other older Windows version. While Microsoft is staking its future on Windows 8, much more PCs rely on Windows 7. Microsoft Corp. says a great deal of licenses for Windows 7 have already been sold given that its release in 2009. Windows 8 is unlikely to approach that amount of usage until at least 2014, based on analyst forecasts.

Desktops, laptops and tablet computers operating on Windows 8 are sold with Internet Explorer 10 already installed. Those with older Windows versions will have to download and install the new browser separately. Despite the fact that Internet Explorer 10 is supposed to procedure Web pages extra promptly and smoothly than its predecessors, it may possibly have restricted appeal to Windows 7 users.

Thats because Microsoft mostly designed Internet Explorer 10 for tablet computer systems and also other devices, including a brand new breed of PCs that have touch-screen displays. Relatively handful of Windows 7 PCs might be controlled with fingers on a display screen.

Microsoft is hoping quite a few website developers will download and install Internet Explorer 10 on their Windows 7 machines and see the browsers prospective for creating on line services additional compelling and dynamic. If that occurs, a lot more sites may possibly contain attributes that make the most of Internet Explorer 10s complete capabilities on the bevy of Windows 8 machines anticipated to be sold during the next year.
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Thursday, April 4, 2013

Whatsapp v2 8 12 S60v3 v5 S 3 Anna Belle Signed

WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for iPhone, BlackBerry, Android and Nokia and yes, those phones can all message each other! Because WhatsApp Messenger uses the same internet data plan that youuse for email and web browsing, there is no cost to message and stay in touch with your friends.

Minimum requirements:

Unlimited internet data plan! Nokia S60 3rd edition, 5th edition, Symbian^3, Symbian Anna, or Symbian Belle Operating System.
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Monday, April 1, 2013

2003 Frequently Asked Questions Microsoft Visio

Visio 2003 is a drawing and diagramming solution that helps people transform business and technical concepts into visual diagrams. Use Visio to formulate, document, and communicate important information and make a professional impact on your audience. Graphics can be a powerful way to communicate information, but most graphics software packages require users to have artistic skills to render effective images; Visio is intended for people who feel uncomfortable drawing freehand but who need visuals to help relay important information.

Create diagrams with Visio 2003 using formatting tools and predefined Microsoft SmartShapes® symbols; add backgrounds, titles and page borders. Q. Who can benefit from using Visio? A. Just about anyone can benefit from using Visio. 2003 Frequently Asked Questions Microsoft Visio Microsoft Office Visio Standard 2003 helps business professionals easily create diagrams that can help them demonstrate how their business operates. For technical users such as IT professionals, software developers, engineers, and space planners, Microsoft Office Visio Professional 2003 provides comprehensive diagramming tools that can help communicate technical information through simple diagrams.

 download Microsoft Visio 2003 Frequently Asked Questions
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