Plasma Vs LCD Vs LED Vs OLED Vs DLP TVs مقارنة

مقارنة

Plasma Vs LCD Vs LED Vs OLED Vs DLP TVs

قد تبدو بعض هذه الأنواع
متطابقة من حيث المظهر و خصوصا عند التبضع , لكن
هذه التشابهية ستنتهي بمجرد أن
تتعمق بالنظر داخل التلفزيون الكبير و الرقيق

Plasma TVs
تستخدم طبقة من خلايا البلازما
شديدة الصغر لخلق الصورة عند تطبيق شحنة كهربائية
معينة , منها :
Panasonic TH-50VX100W
LG 50PS80ED
Panasonic TH-P50G10A
و باستخدام المصطلحات العلمية
نستطيع القول :
تتألف شاشة البلازما من مئات
آلاف الخلايا المستقلة و التي تسمح لنبضات
كهربائية بان تهيج مزيج من الغازات
النبيلة (زينون و نيون و ارجون) مما يسمح له بان
يتوهج و هذا الوهج يضيء النسب
المطلوبة من الفوسفور ( الأحمر و الأخضر و الأزرق
) الموجود داخل كل خلية لينتجوا
اللون المطلوب فتكون كل خلية في جوهرها عبارة عن مصباح نيون مجهري يتحكم به برنامج
وجود في الدارات الالكترونية خلف الشاشة

LCD TVs

تستخدم الكريستال السائل
المضغوط بين صفيحتي زجاج و تخلق الصورة عند تطبيق
شحنة معينة على هذه الكريستالات أيضا
, و هي تتراوح
بين الأجهزة الرخيصة مثل
Changhong LT4268TA
و الاجهزة الغالية الثمن مثل :
Sony Bravia KDL40W5500
Toshiba Regza 42RV600A
و بغض النظر عن استعمال هذه
التقنية في الشاشات أو أجهزة الإسقاط , فان
التقنية الأم تبقى واحدة و هي تسمى

TFTs
او
Thin-Film Transistors

حيث ان الكريستال السائل عندما تصدمه شحنة
كهربائية ينحل لدرجة معينة بحيث يفلتر الضوء
الأبيض الصادر من خلف الشاشة أو من
قلب جهاز الإسقاط فتسمى هذه العملية الطرح
أي طرح كل أطوال الموجات
الضوئية من الطيف ليبقى طول موجي محدد تسمح له
كثافته بالعبور من خلال الكريستال السائل

LED TVs

الكريستال السائل نفسه يستخدم
هنا لكن الفرق يكمن في ضوء الخلفية حيث يتم اصداره
من ما يسمى

LEDs

 و هي الصمامات الثنائية المضيئة

(Light-Emitting Diodes)

الديود او الصمام دارة الكترونية تسمح بعبور

التيار من جهة واحدة عندما تمنعه من الاخرى
بالنسبة لتلفزيونات

LCD

فهي تصدر ضوء الخلفية عن طريق مصابيح مشعة مصفوفة
خلف الشاشة مباشرة

OLED TVs
Organic Light Emitting Diode

الديود العضوي المصدر للضوء هو أحدث تقنية يمكن ان
تشكل تحدياً للكريستال السائل في المستقبل
يتم تشكيل اللون المطلوب في هذه التقنية باستعمال مركبات عضوية
كربونية و التي تصدراللون الاحمر او الاخضر او الازرق حسب التيار التي تتعرض له
تصمم شاشات هذه التقنية بطبقتين او ثلاثة من المادة العضوية و
توضع دخل طبقة من الزجاج الرقيق جدا
و تدعم بطبقة من البلاستيك الصلب لحمايتها
بالاضافة لطبقة المهبط التي تصدر التيار المطلوب لتحريض المركبات
هذه التقنية لا تحتاج ضوء خلفية و بالتالي تستهلك طاقة اقل و يمكن
ان تصمم تلفزيونات برقة اكثر من نظيراتها

DLP TVs
Digital Light Processing

او معالجة الضوء رقمياً تقنية تستخدم اجهزة رقمية
دقيقة لتحرف مرايا دقيقة جدا بمقدار اقل من عرض
شعرة الانسان باتجاه او بعيدا عن
مصباح ابيض داخل الشاشة
هذه العملية تخلق اما بكسل ابيض
او اسود بالاعتماد على درجة الاضاءة المعكوسة عن
المرايا و هذه التقنية تسمح بانتاج 1024 تدرج من اللون الرمادي
اذا الضوء الصادر عن المصباح
الابيض يمر عبر فلتر الوان ثم جهاز التحكم
بالمرايا الدقيقة لتنتج الصورة النهائية
بالنسبة لوضوح الصورة التي تظهر
على الشاشة سواء كانت فلم عالي الدقة او بث
تلفزيوني او لعبة فديو فهو يعتمد على
تكنولوجيا العرض و قدرات معالجة الصورة في التلفزيون

معدل التباين
======
المقصود هنا هو مقدار الاختلاف
بين الجزء معتم من الصورة و الجزء المضيء و يحسب
بقسمة شدة الانارة في اكثر
المناطق انارة على شدة الانارة في اكثر المناطق
ظلمة و بالتالي كلما زاد هذا المعدل كلما كانت الصورة اقرب للواقع و صورة
واقعية = تباين بمقدار لا نهاية =

يجب ان تصل الانارة في اعتم منطقة في الصورة الى صفر
ان معدل التباين يمثل قدرة
الشاشة على اظهار تفاصيل في اماكن التباين في
الصورة على شكل تدرجات الوان دقيقة
جدا بالاضافة للابيض و الاسود
فلو كنت تشاهد فلم مثل

Batman Begins

على شاشة قليلة التباين فان التفاصيل سوف تختفي
تماما في المشاهد المعتمة لان التلفزيون سيكافح
لاظهار الحدود العليا و الدنيا من
الالوان و بمعنى آخر التفاصيل ستضيع في المناطق
المعتمة تماما كما لو كانت مضيئة
بعض مصنعي التلفزيونات يقومون
بزيادة التباين عن طريق ما يسمى التباين
الديناميكي و هو يعني ان الشاشة ستقوم
بخفض كامل الانارة في الخلفية مما يسمح للمزيد من
التفاصيل بالظهور في المشاهد
المظلمة و يطيل عمر الشاشة , حتى انهم قامو
بالاعلان عن تباين يصل الى مليون على
واحد او اكثر مستفيدين من هذه الميزة في الوقت
الذي تدل فيه هذه المعدلات على
التباين المستفيد من تعديل الانارة في الخلفية ,
لذلك يجب ان يتم التركيز على
التباين الثابت و ليس المتحرك او “الديناميكي”
بالطبع شاشات البلازما هي الافضل من ناحية التباين , نظرياً على الاقل بسبب
قدرتها على اطفاء الضوء بشكل
كامل و منفصل لخلية واحدة من الخلايا التي تشكل
الصورة في حين ان شاشات الكريستال تملك مصفوفة
واحدة لاضاءة الخلفية كلها فهي تستطيع فقط تغيير
الانارة لكامل الشاشة لكن يجدر
بالذكر ان الموديلات الحديثة جدا تنافس شاشات
البلازما فيما يتعلق بالتباين

بالنسبة لشاشات الكريستال التي تعتمد على الديود

“LED TVs”

فهي تستطيع التحكم بالخلايا بشكل منفصل كما في
شاشات البلازما , لكن يجب اخذ العلم بان الشاشات
التي تعتمد تقنية

Edge-Lit LED

و التي تاتي عادة بشكل نحيف جدا تمتلك تباين اقل
من التي تعتمد تقنية

BackLit LED

و بالنسبة لشاشات

OLED

فهي تتفوق في هذه الناحية بشكل ملحوظ لتصل الى مستوى
شاشات البلازما و السبب يكمن في طريقة عرض اللون
الاسود حيث انها تقطع التيار

عن المناطق المراد اعتامها كما في شاشات البلازما
و بالتالي فانهما يستهلكان اقل طاقة عند عرض اللون
الاسود و اكثر طاقة عند عرض اللون الابيض

اما شاشات

DLP

فهي لا تتمتع بالاداء المطلوب للمنافسة

زاوية الرؤية
=======
كلما ضاقت زاوية الرؤية قل
المجال الذي تبقى فيه الالوان و يبقى التباين
مثاليين لكن بعض مصنعي التلفزيونات
يعلنون عن زوايا تصل تقريبا الى 180 درجة في بعض
الاحيان لذلك من الافضل المقارنة
شخصيا بما ان الزاوية العريضة مهمة خصوصا في
المنازل الكبيرة

بشكل عام شاشات البلازما تملك افضل زاوية رؤية
بينما تعاني شاشات الكريستال من تبدل الوان و نقص
في الانارة و التباين عند الزوايا العريضة لكن الاجهزة الحديثة تقل فيها هذه
المشاكل , اما شاشات الانارة الخلفية

LED

فهي تبقى افضل من شاشات

LCD

بسبب توزيع الانارة الخلفية اللامركزي

و بالنسبة لشاشات
OLED

فهي تملك زاوية رؤية شبه كاملة لانها تعتمد على
اصدار الضوء و ليس حجبه فتصل زاوية الرؤية الى   170 درجة
اما شاشات

DLP

فهي لا تملك زاوية الرؤية التي تملكها شاشات

LCD

عند المقارنة العامودية اي مثلا الوقوف و الجلوس
حيث تظهر تغيرات الوان طفيفة على شاشات

DLP

الألوان و وضوح الصورة
=============
موضوع الألوان يعتمد على
تكنولوجيا المعالجة و المصنع و الموديل و بشكل عام
فان شاشات البلازما يجب ان تظهر
الوان براقة اكثر من نظيراتها ياتي بعدها الاجهزة
التي تعتمد تقنية

LED

بنوعيها المعتمد على الانارة الخلفية البيضاء او الملونة
اما فيما يتعلق باللون الابيض
فهو افضل في شاشات الكريستال منه في شاشات البلازما
و فيما يتعلق بانعكاس ضوء الشمس
في غرفة الجلوس او في الاماكن العامة فشاشات
البلازما قد لا تكون مفضلة في مثل هذهالحالات

بسبب مشكلة الانعكاسات فاداؤها افضل في الغرف المغلقة
كما انها غير مرغوبة في المناطق
المرتفعة جدا عن سطح البحر ( 6500 قدم ) فهي تصدر
صوت ازيز بسبب مشكلة انخفاض ضغط
الغاز مما يفسر استعمال شاشات الـ

LCD

في الطائرات مع ملاحظة انه تم اصدار شاشات بلازما
تعمل على ارتفاع 9500 قدم
بالتالي عن اختيار شاشة
للمطارات و غرف الجلوس المفتوحة على الخارج يفضل
اختيار شاشات الـ

LCD
اما شاشات

OLED

فهي تتفوق في الالوان بسبب طريقة تشكيلها فكل بكسل
يستعمل الالوان الاساسية الثلاثة لتشكيل اللون
المطلوب اما شاشات الكريستال السائل
فهي تعتمد تقنية الطرح و هي عملية معقدة نسبيا
لكنها تعوض هذا النقص بعدد البكسلات

في البوصة الواحدة
بالنسبة لشاشات

DLP

فهي لا تتمتع بالوضوح و الالون التي تملكها شاشات

LCD

و خصوصا انها تملك فلتر الوان واحد اما شاشات الكريستال
فهي تملك خلية لكل لون

احمر و اخضر و ازرق

داخل البكسل الواحد

الصور المتحركة
=========
و هو موضوع مهم جدا و خصوصا عند
مشاهدة افلام الحركة و الرياضة و الافضل هنا
بالطبع تلفزيونات

OLED

حيث انها تملك اعلى معدل تنشيط تاتي بعدها
البلازما لقدرتها على اعادة تنشيط كل خلية منفصلة
بمعدل اكبر من تلفزيونات الكريستال فلا تظهر غباش او خطوط مقطعة في الحركة
السريعة لكن في الفترة الحالية اجهزة الـ

LCD

تمتلك تردد يصل الى 100

Hz

و هو ضعف الرقم السابق حيث بدأت بـ 50

Hz

و ما تزال تتطور فقد صدرت شاشات كريستال بتردد

200Hz

لكنها لا تزال قليلة في السوق
و اما شاشات

LED

 فهي

تستعمل تقنيات الـ

LCD

فيما يخص هذا الموضوع

و النتيجة : شاشات الكريستال ما تزال دون مستوى

شاشات البلازما

استهلاك الطاقة
========
بما ان شاشات الكريستال تستعمل
مصدر انارة واحد و شاشات البلازما تستعمل مصدر
انارة خاص لكل خلية فان استهلاك
الطاقة اكبر في شاشات البلازما فمثلا
شاشة

LCD

بحجم 42 بوصة تستهلك 200 وات بينما شاشة مماثلة من
شاشات البلازما تستعمل300 وات اي زيادة بمعدل 50%
لكن باستعمال تقنيات توفير
الطاقة فان الفرق يتقلص على المدى الطويل
اما بالنسبة لشاشات

LED

التي تعتمد تقنية

Edge-Lit

فانها تستهلك طاقة اقل بـ 40% و خصوصا التي تعتمد
تقنية توفير طاقة الانارة الخلفية

Energy-Efficient BackLighting

لكن شاشات

LED

التي تعتمد على تقنية

BackLit

 يقع مستوى استهلاكها بين شاشات البلازما و شاشات

LCD
تاتي هنا شاشات

OLED

لتحل في المرتبة الاولى فهي تستهلك اقل طاقة ممكنة بين الجميع

عمر شاشات التلفزيون
============

في بداية عصر شاشات البلازما كانت تعاني هذه الشاشات من قصر
حياتها العملية اي قبل ان تنخفض درجة الاضاءة و جودة الصورة بسبب تلاشي العناصر
الفوسفوريةاما في هذه الايام فقد اصبح
العمر المتوسط لهذه الشاشات 60 الف ساعة استعمال و
العمر المتوسط هو الوقت الذي تستغرقه الشاشة لتصل انارتها الى النصف
اما شاشات

LCD

فهي تعتمد على جهاز الانارة الخلفية و الذي غالبا
يتجاوز عمره 60 الف ساعة في حين تتجاوز حياة شاشات

LED

الـ 100 الف ساعة
و بالنسبة لشاشات

OLED

فهي تعاني من قصر حياة العنصر العضوي المشع
المسؤول عن الازرق كما ان الاحمر و الاخضر ليسا
بمعمرين ايضا
في هذه الناحية تتفوق شاشات

DLP

على باقي الانواع بعمر مديد و محافظة على الالوان
حتى ان المصباح الخلفي يمكن تغييره بسهولة
و اعود للتذكير ان نهاية حياة
الشاشة لا يعني انها ستتوقف عن العمل لكنه يعني
عادةً ان انارتها الخلفية ستصل الى النصف

في الشاشات التي تعتمد الانارة الخلفية
يجدر بالذكر ان المشكلة التي تسمى

Burn-In

و التي كانت تعاني منها شاشات البلازما في بداية
عهدها تم التخلص منها باستخدام التقنيات مضادة و
شاشات التوقف و تقنية توفير
الطاقة و هي مشكلة لا تعاني منها شاشات الكريستال
السائل و لذلك فهي المفضلة في
شاشات الكمبيوتر بنوعيها الى جانب استهلاكها الاقل
للطاقة و احتوائها على بكسلات
اكثر في مساحة بوصة مربعة
Burn-In

هي عملية عرض صورة واحدة لمدة طويلة الى درجة ان
الخلايا تحتفظ بها حتى بعد عرض صور مختلفة كما في
خلفيات سطح المكتب او شعارات القنوات الفضائية

الأسعار و الأحجام
=========

فيما يتعلق باختيار النوع
المناسب للحجم المناسب فان الشاشات الاصغر من 42
بوصة تعتبر افضل اذا كانت من نوع

LCD

حيث انها ارخص و في نفس الوقت فان مشاكل التباين و
الانارة لا تظهر بوضوح عليها و ستجد ايضا انها
اوضح من نظيراتها من شاشات البلازما
اما ان كنت تطمح لشاشة مسرح
منزلي اكبر من 42 بوصة فان خيارك الافضل سيكون
شاشة بلازما من حيث الوضوح و
التباين كما انها ستكون ارخص من نظيراتها من شاشات
الكريستال السائل لكنها ستكون اثقل وزناً
اما تلفزيونات

LED

فهي تاتي باحجام شاشة اكبر من

LCD

و تكون اغلى بحوالي 20% منها لكن عند اتخاذ قرار
شراء مبني على التكلفة الكلية او طويلة الامد فان شاشات

LED

بتقنيات توفير الطاقة تكون الانسب
و اما شاشات

DLP

فهي الارخص حتى على المدى البعيد اذا اخذت تغيير
المصباح الخلفي بعين الاعتبار
بالنسبة لشاشات

OLED

فهي غير اقتصادية ابدا و اسعارها غير قابلة للهبوط
إلا عندما يصبح الانتاج بكميات كبيرة لكن في
المقابل فهذه التقنية الواعدة تعدنا
بان نصل لشاشات مرنة و كبيرة مع الوقت مما يسمح
بتطبيقات عملية اكثر
في النهاية مهما تكن التقنية
التي ستختارها تاكد من ان تقارن عدة شاشات في
المتجر بحيث تكون مصفوفة بجانب بعضها
البعض و لا تنسى التقنيات و الخصائص المتوفرة فيها
فهي تشكل جانب مهم من قرار الشراء
و فيما يلي جدول بالتكنولوجيا المتفوقة في النواحي التي تكلمنا
عنها و المقارنة بين اهم و اشهر تقنيتين

LCD vs Plasma

Picture Quality Considerations

Contrast/Black Level : Plasma

Brightness : LCD

Color Accuracy : Plasma

Viewing Angle : Plasma

Functional Consideration

Computer Use : LCD

Fast Moving Video : Plasma

Screen Glare : LCD

Longevity : Draw

Screen Burn In : LCD

Other Considerations

Production Size and Cost : Plasma

Power Consumption : LCD

Price and Value : Plasma

Totals :
LCD = 6
Plasma = 7

=============

Current Generation :
Electroluminescent display (ELD)
Vacuum fluorescent display (VFD)
Light emitting diode (LED)
Cathode ray tube (CRT)
Liquid crystal display (LCD) . (TFT · LED backlight)
Plasma display panel (PDP)
3LCD
Digital Light Processing (DLP)
Liquid crystal on silicon (LCOS)
Next Generation :
organic light-emitting diode (OLED) .

(roll-up display · Active-matrix ·Phosphorous)
Surface-conduction electron-emitter display (SED)
Field emission display (FED)
Laser TV
Ferro Liquid display (FLD)
Interferometric modulator display (IMOD)
Thick-film dielectric electroluminescent (TDEL)
Nanocrystal display
Quantum dot display (QDLED)
Time-multiplexed optical shutter (TMOS)
Telescopic pixel display (TPD)
Liquid crystal lasers (LCL)
Laser Phosphor Display (LPD)

Windows 7 AT-Tablet Launched against the iPad

Well, Microsoft CEO Steve Ballmer did promise earlier this year that
Windows 7 tablet PCs would be coming by the end of 2010.

With the HP Slate 500 having gone live last week, albeit
quietly enough that customers are bound to almost not notice it at all,
additional slates are starting to emerge.

It is the case of AT-Tablet, which maker Dutch Ambiance Technology says
it launched with the specific purpose to fight Apple’s iPad.

According to Dutch Ambiance Technology, the AT-Tablet is the first Windows 7 operated 3G consumer Tablet to hit European markets.

The promise from the Hilversum-based OEM is that the AT-tablet delivers the same performance as modern laptops, and that unlike the iPad it allows users to take advantage of all the Windows ecosystem of software offerings.

"Microsoft even called to congratulate us with the first professional answer to all the Android commotion," noted Ambiance Technology managing director Eric Schouten.

The AT-tablet will hit stores next month, and will come with
Windows 7 Home Premium pre-installed.

The slate features a 10’’ capacitive multi touch LCD screen, and is powered by an Atom n450 processor and no less than 1 GB of RAM.

With a HDD of 160 GB, the Windows 7 slate certainly has Apple’s iPad beat in terms of the storage capacity it offers users by default.

However, customers will also be able to expand storage with
removable cards, the company explained.

AT-Tablet also sports a 3G SIM
card slot, and can support a variety of devices connected through USB, because
it is running Windows 7 after all.

Customers can take advantage of a wireless 3G connection in order to surf the web. In addition, the AT-Tablet sports Bluetooth support and a mini VGA connector which allows users to connect the device to a monitor.

With the built-in 1.3 Mp webcam, microphone and stereo speakers people can connect with friends via instant messaging right from the device.

Of course, being a Tablet PC, the AT-Tablet is designed primarily to allow for internet navigation as well as for media consumption scenarios.

"You carry your digital life with you. This tablet makes you more mobile, frees you from an endless dependency on wires, sockets or special app stores," Schouten added.

Has Microsoft Missed the Tablet Boat?

A report from Forrester indicates consumer interest in Windows-based tablets has plummeted over the last few months. It's true that Microsoft's activities in the tablet market have been minimal so far. However, consumers may be uninterested in Windows tablets simply because there's so little to see at present, a predicament which could change once Microsoft starts its Windows 8 blitz.

Windows 8 tablets may have a very difficult time competing when they finally hit the market, according to the findings of a recent Forrester Research report.

U.S. consumer desire for Windows tablets halved between the first and third quarters of this year, said J.P. Gownder, one of the report's authors.

That's because Microsoft's (Nasdaq: MSFT) going to be late to the party, Gownder stated.

However, just last month, the Boston Consulting Group found that more than 40 percent of existing tablet owners in the U.S. wanted a Windows tablet.

So just what is going on? Which figures should we believe?

The Sum of Forrester's Calculations

Among modern tablet platforms, Microsoft will be the fifth mover after iPad, Android tablets, the now-defunct HP (NYSE: HPQ) webOS Touchpad tablet, and Research In Motion's (Nasdaq: RIMM) BlackBerry PlayBook tablet, Forrester concluded.

Redmond's product boffins could learn from the mistakes these other vendors made, but the competition will have streaked ahead in the meantime, probably launching third-generation products by then, Forrester suggested.

Meanwhile, new players, such as Amazon (Nasdaq: AMZN) with the Kindle Fire and Barnes & Noble (NYSE: BKS) with its Nook tablet, are redefining the market.

Forrester's figures show that in Q1 2011, 46 percent of consumers wanted a Windows tablet, but that figure fell to 25 percent by Q3.

Out of Sight, Out of Mind?

"Consumers aren't that interested in buying Microsoft tablet futures that might be delivered a year or two from now, when they're seeing people using tablets today," Carl Howe, director of anywhere consumer research at the Yankee Group, told TechNewsWorld.

"Microsoft's roadmap-based product strategy may be attractive to IT organizations with annual budget cycles, but it just doesn't fly with millions of impulse-buying consumers," Howe added.

Further, the tablet market isn't one where the OS used really matters much, Howe pointed out.

"The Yankee Group's upcoming tablet landscape report finds that buying intent for consumers is focused largely on the hardware brand, and not the operating system," Howe elaborated.

"As such, mixed-brand products such as a Lenovo tablet powered by Windows 8 that you have to shop for at Best Buy (NYSE: BBY) just aren't going to be as easy to sell to consumers as an Apple (Nasdaq: AAPL) iPad that you can buy at the Apple Store," Howe said.

On the Other Hand ...

Forrester might not have been looking at the same set of indicators as the Boston Consulting Group (BCG), which in October released a report that was more sanguine about the Win 8 tablet's chances.

More than 40 percent of tablet consumers in the U.S. want one that runs Windows, and that figure goes up to 53 percent when people who don't use tablets are included, BCG stated.

That's similar to the situation in China, where 44 percent of consumers want a Windows tablet, BCG said.

Perhaps the reason can be found in the report -- BCG believes we'll soon see different types of tablets targeting different markets.

The Kindle Fire is one example of a device targeted to a specific market. It's not aimed directly at the iPad but at people who want to consume content offered by Amazon.com.

BCG and Forrester's Gownder did not respond to our request to comment for this story. Microsoft kept mum, with spokesperson Lacretia Taylor declining to comment.

When the Sleeper Wakes

It could be that Microsoft's a sleeping giant whose entrance will jolt the tablets field.

Further, Microsoft has tremendous clout in the enterprise and might leverage that to push Windows 8 tablets when they are finally launched.

"Never underestimate a company's installed base," Jennifer Jacobson, director of public relations at Retrevo, told TechNewsWorld. "I'd argue that there's significant room in the tablet market for competition, especially from a force like Microsoft."

If Microsoft can offer "an affordable, fun or easy-to-use tablet that syncs flawlessly with people's existing Windows-based computers and phones, and has access to a marketplace of popular apps, it's safe to say there are a lot of people who would want to get their hands on one," she said.

original post here

Nightlight IR Detector Hack

Nightlight IR Detector Hack
This hack is so simple that, if there were a Book of Hacks, this one would be found at the top of the first page of Chapter 1, Volume 1. Infrared (IR) is electromagnetic radiation with a frequency lower than red light (infra means below) and higher than microwaves. Because infrared is not visible to the human eye and can pass through opaque objects, devices that utilize it can be difficult to troubleshoot. Moreover IR can be a health hazard because it won't trigger the eye's blink reflex. Many nightlights use a photosensitive circuit element to automatically switch a light source on or off when the ambient light level falls below or rises above a certain threshold. These photosensors are often still sensitive well outside the range of visible wavelengths which means they can be used to detect some types of IR.

The video below demonstrates the use of an inexpensive nightlight to detect the IR emitted from a remote control. The first part shows how to use the nightlight as a detector even if the ambient light level is high by simply putting the remote very close such that it shields the photosensor from the room's lights. Notice that the nightlight turns off when IR is detected. The second part demonstrates the nightlight's response when the room's lights are off and the distance of the IR source is varied. If you watch closely you'll see the camera detect some reflected infrared a couple times. You might be wondering "Why bother with a nightlight if a camera can detect IR?" Well, the nightlight has the advantage of being inexpensive, plus there are some cases where using the nightlight will be quicker and easier.



The next video shows the nightlight's response when it is irradiated by an IR jammer. The purple light captured by the camera is not visible to the naked eye. Notice how the nightlight doesn't flicker when lit by the IR jammer like it does when lit by the remote control. The flicker is a result of the remote control turning off it's infrared LED while it pauses before resending a code.



Placing an IR pass filter over the photosensor allows the nightlight to be used as an IR detector even when the ambient light level is above it's normal cutoff threshold. I tested two kinds of black electrical tape and one type of red electrical tape as IR filters, but both failed. I had success in using IR plastic, taken from my electronics junk box, to block out enough ambient light to turn on the nightlight while still allowing directed IR to pass and turn out the nightlight. However, the filter would not stop directed blue LED light and red laser light from turning of the nightlight.

Final Thoughts
Some green lasers from unscrupulous manufacturers emit a potentially hazardous amount of infrared. By a clever use of filters or a diffraction grating it may be possible to use a nightlight as an IR hazard indicator.

I think science educators may find photosensitive nightlights to be inexepensive yet useful tools for demonstrating concepts like transducers and detecting light beyond the range of human vision.

Original Post Here

Privacy monitor hacked from an old LCD Monitor

Finally you can do something with that old LCD monitor you have in the garage.
You can turn it into a privacy monitor! It looks all white to everybody except you, because you are wearing "magic" glasses!
All you really have to have is a pair of old glasses, x-acto knife or a box cutter and some solvent (paint thinner)



Here is what I used:
an LCD monitor of course
single use 3D glasses from the movie theater (old sunglasses are just fine)
paint thinner (or some other solvent such as toluene, turpentine, acetone, methyl acetate, ethyl acetate etc)
box cutter (and CNC laser cutter :) but that you don't really need, I'm sure x-acto knife and a steady hand would do just fine)
screwdriver or a drill
paper towels
superglue

Step 1Take the monitor apart

Find an old monitor that you are willing to sacrifice.
Take off the plastic frame by unscrewing all screws from the back.

Step 2Cut the polarized film

 



Most LCD monitors have two films on the glass - a polarized one to filter out the light you are not supposed to see, and a frosted anti-glare film. The anti-glare film we don't need, the polarized one we do - it is used for the glasses.

So, grab you cutting tool and cut the films along the edge. Don't be afraid to press, metal wont scratch the glass, unless there is sand or other abrasives on it.

Then, start peeling. Make sure to save the polarized film, also remember the orientation.

Step 3Clean the film adhesive

 

 After you remove the film, the glue will likely remain stuck to the glass, so here comes the messy part.
With some solvent, soften the glue and wipe it off with paper towels.
I started with OOPS, but that was not fast enough so I got some paint thinner.
I found out that if you cover the screen with paper towels and then soak them in paint thinner you can let it sit longer and dissolve the adhesive without running and evaporating.
Scrape off the soft glue with a piece of plastic or wood.
Be careful not to get paint thinner on the plastic frame, because it will dissolve it.

Step 4Monitor - done

 

 After cleaning the adhesive, assemble everything back the way it was. Before even making the glasses, you can test the monitor with the polarized film!
Notice how the upper left corner looks clear, because it has the anti-glare film removed. That is the part we are going to use to make the glasses.

Step 5Pop the lenses out

 For the glasses, I used single use 3D glasses from the movie theater, but you can use whatever you want.
Pop out the lenses or take the glasses apart if you can.

Step 6Scan, Trace, Cut

 

 If you are going to use a cnc blade or laser cutter, scan and trace the parts.
You can find a local vinyl or laser cutting service, or you could send them to an online service like CutYourWay.com
I scanned the frames so I can use them as a reference for the lens orientation.
Remember, this is a polarized film so the angle is critical. Back and front also matters.
If you don't have access to a cnc cutter or you don't want to wait for an online service, you can probably tape the old lenses on the film and then cut them out with an x-acto knife.

Step 7Reassemble glasses and enjoy!

 

 

 

 Finally assemble the glasses and you are ready for some fun!
People might think you are crazy, staring at a blank white screen wearing sunglasses!
But I guess that makes it even more fun!

Original post here

What Linux noobs Need to Know

Linux is like that classic muscle car, in that if you are willing to put in the hours and don't mind spending your weekends under the hood, you'll have yourself a sweet ride at the end of the day and the knowledge you built and tweaked it with your own two hands," said Slashdot blogger hairyfeet. "But if you aren't willing to put in the work, all it is gonna do is make you frustrated."

 It's a sad fact of life that none of us are born experts in much of anything, and certainly not in Linux.

Noobs are how we must all begin our adventures in the world of FOSS, in other words, much as we may try hard to pretend otherwise.

Remember those days? Well the folks over at TuxRadar certainly do, and not long ago they launched an interesting little discussion about it for the "ultimate newbie guide" they're planning to put together.

'Anything You Wish You Knew Then?'

"The plan is to explain what Linux is, what free and open source software is, how to get started with it, all the cool things it lets you do, and so much more," the TuxRadar team explained.

Toward that end, they solicited readers' own experiences and insights.

Specifically, "when you first started using Linux, is there anything you know now that you wish you knew then?" they asked.

More than 50 enthusiastic contributions later, it was clear they'd have no shortage of material for a valuable resource. Down at the Linux blogosphere's Punchy Penguin Saloon, meanwhile, the conversation quickly took on a life of its own.

  "Every n00b, to be deemed worthy, must possess the Two Virtues of the Linux Acolyte: Patience and Curiosity," began Barbara Hudson, a blogger on Slashdot who goes by "Tom" on the site.

"Patience, because sometimes things are just different enough to throw you off, and curiosity to keep you motivated when your patience wears thin like a cheap rug from everyone saying, 'Just google it, n00b!' or 'RTFM!'" she explained.

Also, "please don't handicap yourself by making your first experience be on some old oddball hardware that will be so slow that it turns you off the whole experience," Hudson added.

'Go for the Quick Default Install'

  To make things easier, newbies should "just go for the quick default install the first few times -- you're just getting your feet wet, and you're going to wipe it down and install a few different distros until you find the one that's right for you, so don't sweat things like getting partitioning picture-perfect the first time," Hudson advised.

"It's your new toy -- play with it, note what you like/hate about it, and move on to the next," she added.

Meanwhile, when obstacles arise, "remember: if the man page for a particular command is too cryptic (or wasn't installed), 'apropos' + the command name should give you lots of related material," Hudson pointed out. "'Apropos' might even help keep you from looking like a n00b online, which makes it quite apropos for n00bs."

'Go Ahead and Try Something Hard'

  "Try something hard," suggested consultant and Slashdot blogger Gerhard Mack.

"You can install and maintain your average Linux distro without ever touching the command line, but you don't learn as much that way," he explained. " Once you have mastered an easy version of Linux, go ahead and try something hard such as Linux From Scratch."

Slashdot blogger hairyfeet was more cautious.

'There Is No Escaping the CLI'

  "Ask yourself this question: 'Am I willing to learn the command line, and to invest the time to learn bash and how to edit bash scripts and commands?'" hairyfeet advised. "If the answer is 'no,' then you shouldn't be on Linux -- it's that simple."

Hairyfeet has tried "every 'user friendly' distro under the sun," he said, "and there simply is no escaping the CLI -- either something goes wrong or an update borks a driver and you'll end up in the CLI."

Ultimately, then, "Linux is like that classic muscle car, in that if you are willing to put in the hours and don't mind spending your weekends under the hood, you'll have yourself a sweet ride at the end of the day and the knowledge you built and tweaked it with your own two hands," hairyfeet concluded. "But if you aren't willing to put in the work, all it is gonna do is make you frustrated."

'Pass the Help Forward!'

  Chris Travers, a Slashdot blogger who works on the LedgerSMB project, had three suggestions for newcomers to Linux.

"The first one is have someone sit down with you and answer your questions, in a hands-on way," he explained.

"The second one is to get someone who is friendly and listens, who can help you ramp up your skills," he added.

"The third one is, please pass the above help forward!" Travers concluded.

'There Is Nothing You Cannot Do'

  Last but not least, blogger Robert Pogson had numerous specific suggestions on the tip of his tongue:

• "In Debian GNU/Linux, 'apt-cache search keyword' is your friend;


• 'apt-cache search keyword | grep keyword' is your lover -- with these two commands you can search for and find any package of 30K packages in the repositories and install them in seconds with 'apt-get install package';


• Using the APT package manager, you update all your packages, applications, utilities, and Linux itself with a single command: 'apt-get update;apt-get upgrade';


• In GNU/Linux, any PC can be a client, a server, or both simultaneously because no one is trying to charge extra money for such functionality;


• If you have more than one GNU/Linux PC (or virtual PC), learn to use the X window system and openSSH to manage one PC from another and to interact with one PC from another";


• and finally, Linux Girl's favorite: "There's nothing you cannot do with GNU/Linux."

Carrier IQ : Your phone's secret recording device !!

NEW YORK (CNNMoney) -- Carrier IQ is a piece of software installed on millions of mobile phones that logs everything their users do, from what websites they browse to what their text messages say.

No, it's not part of some great Orwellian plot; it's a diagnostic tool that carriers say plays a crucial role in helping them assess and troubleshoot their networks. But the recording app, which flew under the radar for years until security researchers drew attention to it recently, is setting off red-alert privacy and security alarms.

It's also spotlighting how little customers -- and, sometimes, the carriers and manufacturers themselves -- know about what goes on under the hood of their data-stuffed mobile devices.

Reports about Carrier IQ's hair-raisingly detailed tracking capabilities began swirling in the tech press several months ago and gained steam after Android developer Trevor Eckhart posted an analysis of the software's data logs.

But on Monday, Eckhart followed up with a 17-minute YouTube video showing how the software secretly runs on his HTC EVO 3D Android phone and logs every key press, every text, and the full URL of every website he visits. It recorded that data even from websites that use security encryption designed to prevent that kind of tracking.

Then word began spreading about just how ubiquitous Carrier IQ's software is. It's on an estimated 150 million mobile devices.

AT&T (T, Fortune 500) and Sprint (S, Fortune 500) confirmed to CNNMoney that handsets on their networks run Carrier IQ's software and transmit information from it back to them. T-Mobile, which was not immediately prepared to comment, also uses Carrier IQ to monitor devices on its network, researchers say.

Verizon Wireless (VZ, Fortune 500) says it doesn't use Carrier IQ's software. It also claims that it doesn't run anything similar, though Verizon's rivals all disputed that, insisting that modern networks can't operate without these kinds of diagnostic tools.

Researchers have found the software on multiple devices running Google's (GOOG, Fortune 500) Android operating system.

Apple (AAPL, Fortune 500) also confirmed Thursday to CNNMoney that the software is running on some of its mobile devices, but the company says it stopped supporting it in the latest version of iOS and will completely eliminate Carrier IQ from all iPhones and iPads in an upcoming software update.

What the logging tool does: Carrier IQ -- and several of its major customers -- say its software is being misunderstood.

Carrier IQ says the core purpose of its tool is to uncover broad trends across a network. Its software can help carriers find out where calls are dropping and why, and zero in on device glitches. If a specific handset line from HTC, say, has a battery life problem, Carrier IQ's software will help surface the problem. 

Sprint, for example, said it uses Carrier IQ to root out network problems.

"We collect enough information to understand the customer experience with devices on our network and how to address any connection problems," Sprint said in a prepared statement. "We do not and cannot look at the contents of messages, photos, videos, etc., using this tool. The information collected is not sold and we don't provide a direct feed of this data to anyone outside of Sprint."

But as Eckhart's video and other security investigations have illustrated, Carrier IQ is logging a shockingly extensive cache of data.

In response, Carrier IQ issued a statement saying that it doesn't "record," meaning it doesn't actually transmit to the carriers or anyone else, most of the information it stores on phones.

It's a technical but meaningful distinction. Sprint and AT&T said that they do not and cannot collect the kinds of detailed information that the Carrier IQ software tracks on the phone.

Independent security analyst Dan Rosenberg has studied Carrier IQ's software and several wireless providers' user of it. As he puts it: "People need to recognize that there's a big difference between recording events like keystrokes ... and actually collecting, storing, and transmitting this data to carriers, which doesn't happen."

He added: "After reverse engineering Carrier IQ myself, I have seen no evidence that they are collecting anything more than what they've publicly claimed: anonymized metrics data."

Still, he didn't let Carrier IQ off the hook completely. There are significant privacy concerns -- which both Carrier IQ and its customers seem to have overlooked -- associated with having a big chunk of personal data stashed on your phone.

Rosenberg called that software design approach "pretty bad."

Christopher Soghoian, a cyberprivacy researcher and fellow at human rights organization Open Society, echoed that view.

"Carrier IQ doesn't seem as nefarious as incompetent, but that may not be enough to allay the legitimate concerns of the public," he said. "There would be huge issues if this data were transmitted to a carrier, but even if not, it presents huge concerns. This would be a gold mine for a hacker."

Soghoian thinks that Carrier IQ has far more access and stores much more information on phones than it should.

Yet users are essentially powerless to stop it. The software is so buried in the device's operating system that the average consumer can't possibly delete it, and doing so would void the phone's warranty.

"It's not reviewed by Google's security team, it's not audited, it may not get regular security updates, and you really don't want one app to have all that information," Soghoian noted.

Google insisted that Carrier IQ is installed at the manufacturer and carrier level. A company spokesman said it had no involvement with the software's appearance on its Android devices.

One thing is clear: This mess isn't over. What began as a wonky technical issue is becoming the subject of widespread public scrutiny.

Senator Al Franken, a Democrat from Minnesota, fired off a letter to Carrier IQ on Thursday demanding answers. Franken said he is "very concerned" by reports that the software "is logging and may be transmitting extraordinarily sensitive information."

He's far from the only one with those concerns.