Introduction: Android is a Linux-based mobile phone operating system developed by Google. Android is unique because Google is actively developing the platform but giving it away for free to hardware manufacturers and phone carriers who want to use Android on their devices. Beyond the Phone: A modified version of Android is used in the Google TV, the Barnes & Noble Nook eReader, the Samsung Galaxy Tab, and countless other devices. Parrot makes both a digital photo frame and a car stereo system powered by modified versions of Android. Open Handset Alliance: Google formed a group of hardware, software, and telecommunication companies called the Open Handset Alliance with the goal of contributing to Android development. Most members also have the goal of making money from Android, either by selling phones, phone service, or mobile applications. Android Market:These apps can be downloaded from the Android Market. If the app costs money, you pay for it using Google Checkout. T-Mobile also has an agreement to allow their phone customers to purchase some apps and have the fee added to their monthly phone bill. Some devices do not include support for the Android Market and may use an alternative market. Service Providers: The iPhone has been very popular for AT&T, but unless you void your warranty to unlock it, you can only use an iPhone with AT&T. Android is an open platform, so many carriers can potentially offer Android-powered phones. That doesn't mean individual carriers won't lock the specific phone they sell you to their service, but every major carrier in the US offers an Android phone. Android is currently the fastest growing phone platform in the world. Data Plan: To use Android on a phone, you need a data plan on top of your voice plan. You can't even activate an Android phone without a data plan enabled. Some networks in the US offered tiered data service, and some offer unlimited plans. Anyone can download the SDK (software development kit) and write applications for Android phones. Google doesn't screen developers or applications. Google Services: Because Google developed Android, it comes with a lot of Google services installed right out of the box. Gmail, Google Calendar, Google Maps, and Google Web search are all pre-installed, and Google is also the default Web page for the Web browser. However, because Android can be modified, carriers can choose to change this. Verizon Wireless, for instance, has modified some Android phones to use Bing as the default search engine. Touchscreen: Android supports a touch screen and is difficult to use without one. You can use a trackball for some navigation, but nearly everything is done through touch. Android also supports multi-touch gestures such as pinch-to-zoom in versions 2.1 (Eclair) and above. Keyboard: The initial release of Android required a separate keyboard. However, "Cupcake," (Android 1.5) and later editions have all supported an on-screen keyboard. That means you can use models like the Verizon Droid 2 that include a slide-out physical keyboard or the HTC EVO that rely entirely on the touch screen. The Bottom Line: Android is an exciting platform for consumers and developers. It is the philosophical opposite of the iPhone in many ways. Where the iPhone tries to create the best user experience by restricting hardware and software standards, Android tries to insure it by opening up as much of the operating system as possible. This is both good and bad. Fragmented versions of Android may provide a unique user experience, but they also mean fewer users per variation. That means it's harder to support for app developers, accessory makers, and technology writers (ahem). Because each Android upgrade must be modified for the specific hardware and user interface upgrades of each device, that also means it takes longer for modified Android phones to receive updates. Fragmentation issues aside, Android is a robust platform that boasts some of the fastest and most amazing phones and tablets on the market.

What is 3D printing?

3D printing is a method of manufacturing everything from tools to shoes to jewelery, or even car and aerospace parts using a computer-controlled printer. The fundamental rule of 3D printing is that it’s an additive manufacturing technique, unlike machining, turning, milling, and sawing which are subtractive.

While there are different kinds of 3D printing, all 3D objects are generally built out of layers. A 3D printer starts with the bottom layer, waits for it to dry or solidify, and then works its way up. This layering process differs depending on the printer and the material it works with — metal, plaster, polymer, resin — but it also depends on whether it’s an industrial or commercial 3D printer.
Industrial vs. commercial

While consumer- and small business-oriented 3D printing is only just taking off, mostly thanks to the MakerBot and RepRaps, 3D printing has been used in an industrial setting for 30 years. Industrial 3D printers tend to be very large and very expensive, but at the same time they are a lot faster than commercial printers. Some industrial printers can print with multiple nozzles at the same time, or even use metal (more on that later). For the most part, industrial printers are nearly always used for rapid prototyping (usually by architects, automakers), but sometimes 3D printed objects — especially in the case of metal objects — are used in final products.

Consumer-oriented 3D printers are cheaper, smaller, slower, and are usually lower resolution than their industrial counterparts. Consumer printers are still used for rapid prototyping, but they’re also used by people who just like the idea of printing stuff out. Generally, consumer printers use thermoplastic extrusion — i.e. it dribbles out tiny dots of melted plastic.
Different printing techniques

3D printing -- the original is on the left hand sideDepending on the material used, how many colors you want, the resolution you require, and how much money you’re willing to fork out, there are at least five popular 3D printing methods to choose from. Some are very similar, but some are really rather crazy (or brilliant).

Fused deposition modeling – The most common 3D printing method is fused deposition modeling (FDM). The raw material with this process is a spool of plastic or metal wire, which is melted and placed by the printer’s nozzle. It quickly hardens, and then the next layer can be added. As far as commercial printers are concerned (like the MakerBot), FDM always uses plastic wire (filament) and is usually called “thermoplastic deposition” in layman’s terms
Inkjet printing — Using special inks (resins and binders) it’s possible to build up a 3D model using a device that’s very similar to a home or office inkjet printer. Layer upon layer of resin and binder are added until an object is created. This is the only 3D printing process that allows for custom colors.
Selective laser sintering – Sintering is the process of creating solid objects from powders, and in the case of selective laser sintering (SLS) the powder can be metal, plastic, ceramic, or glass. Basically, SLS uses a pulsed laser to “draw” the desired cross-section. The powder fuses, and then then the laser forms the next layer on top. This is very much an industrial method, as it requires a rather strong laser.
Digital light processing – With DLP (yes, the same technology behind DLP projectors), a vat of liquid polymer is turned into a very strong solid by exposing it to light. Very high accuracy/resolution can be achieved with this technique — and again, this is an industrial method. Stereolithography is similar to DLP manufacturing, but a lot more expensive.
The others – Finally, there are a few 3D printing techniques that aren’t used extensively, but could be in the future. Resin can be cured using LEDs (similar to the DLP approach); 2-photon photopolymerization can be used to create ultra-small 3D-printed features; laminated object manufacturing uses bits of paper or card stuck together that are then cut out using a laser.

The future of 3D printing

Star Trek teleporterWe’ve already alluded to a few uses for 3D printing — prototyping, making stuff at home — but it’s worth diving into some of the crazier things that 3D printing is capable of now, and what it will be capable of in the future.

3D printers can be used to create titanium aircraft parts, human bones, complex, nano-scale machines, and more. In the future, it’s fairly safe to assume that we’ll be able to manufacture almost anything with a 3D printer — and everything we can’t make with a printer (clothes, textiles), automated CNC machines, or something like them, will take care of. Ultimately, 3D printers might also be the key to matter replicators, just like in Star Trek. It’s important to note that we already have very accurate tools for creating 3D models of existing objects; we have the ability to scan a cup, and then create an exact copy using a 3D printer.

Eventually, one day, you will walk up to a 3D printer and say “make me an iPad,” and it will make you an iPad. If we can create 3D printers with atomic-level resolution, they might also usher in another Star Trek gadget: teleporters. There’s also the (rather worrying?) fact that many commercial printers are labeled as “self-replicating,” in that they’re capable of printing their own replacement parts. In other words, if we gave a 3D printer some kind of artificial intelligence, who knows what it would into.