Tech Terms of the Week

Tech Term of the Week #7: Touchscreens

2010-01-08T19:09:00.000-08:00

Touchscreens have always been used to provide a intuitive interface that any user can learn to use. Since the iPhone's release back in July of 2007, touchscreens has been more and more prevalent especially in the cellphone market, where keypad phones are now a rarity.

Now many of you might be wondering how this seemingly devil magic works and today hopefully I can explain them before my brain decides to stop functioning.

There are 3 general kinds of touchscreens, resistive, capacitive, and infrared.

Resistive touch screens work due to the pressure of you fingers making electrical contacts on the screen

As you can see from the picture a resistive touchscreen has two conductive layers separated by a minuscule gap. When you finger pushes on the screen the two membranes come into contact and a voltage can be detected by the screen controller and the x and y coordinates can be pinpointed by seeing where the voltage came from. These types of touchscreens were the first to be utilized in mass production, and are characterized by a slight squishiness of the screen. An example of a resistive screen is the Nintendo DS

The next and more recent type is capacitive touchscreens. Almost all modern touch screens use this technology for touch. Capacitive screens use the conductivity of you human flesh to detect motion. The actual scientific explanation is quite confusing and long so I'm going to skip it and give a gross oversimplification. Actually this is totally an excuse because I actually have no idea how it actually works down on the technical level

Basically a current is fed through a conductive panel. When you finger touches it it alters the flow of the current enough so that a receiving electrode can detect it. Based on where you touch the current will be different to the receiver and this is how the touch is detected. This technology can be used to detect multiple touches by having the receiver look for different patterns of the received current. The downside to this is that only conductive materials can be used as pointers, so for example if you had gloves, you could not use your laptop touchpad, your Apple scroll wheel, or your iPhone screen.

Last we have infrared touch screens. How this works is having a grid of infrared lights.

So you have at one end a row of diodes and at the other detectors. Same thing with the columns.
When you touch the screen you finger blocks the light from reaching the detector in both the x and the y axis. Using this information the controller can tell the device where the touch has occurred.

So these are the three main forms of touch screens with capacitive screens being most common followed by resistive and infrared. Hopefully this is explained how you snazzy new cellphone can tell that you touched the take call button instead of hanging up on person on your phone.

Tech Term of the Week #6: Special: The tech behind AVATAR

2009-12-19T20:38:00.000-08:00

So this Friday I went to see Avatar. AND. THAT. MOVIE. IS. FUCKING. AWESOME. THE ENTIRE TIME MY MIND WAS BEING CONTINUALLY BLOWN AWAY. So during the movie, Josh Goldberg stupidly comments, "HOW THEY HELL DO THEY DO THAT?!?!?!?!?" Well in this very special post, im going to explain some of the awesomeness that went into James Cameron's Avatar.

First up we decided to bite the bullet and pay the premium price to watch the movie in 3D. 3D has usually been a gimmick to drive little kids to go watch theses movies but I have to say, The 3D in Avatar is very spectacular. Now 3D in movies is actually 2 flat images both shifted slightly to the right and the left. These images are projected at the same time on the same screen and that is why when you take off your glasses, the image seems fuzzy. Now the objective is for your right and left eyes to see the respective images separately. This used to be done by shifting the hues of the two videos. To filter out the images you would have to wear the glasses we all come to associate with 3D.

GLASSES!!!!

The colored lens filter out the colors for each eye. The blue lens will only let blue light through and the red only lets red. So if you make what you want the left eye to see red, and the right, blue. This makes your eyes see two separate images. Your brain interprets this as depth and starts thinking in 3D.
Another way to do this (the modern way) is to use polarized lens. This little graphic helps explain polarized lens very nicely

So if you can think of polarized lens as a lens with slits in it. If the slits are vertical they only let in light that is vertically moving

if the slits are horizontal, only horizontal light gets through

and last if u have both of them no light gets through, but why would you want that?

so the same concept of having two images that are slightly shifted, but this time instead of offsetting the hue, they are projected using two different types of light. The lenses on the glasses only let in the specific image and again it fools your brain into thinking in 3D

Avatar had the most detailed environments I have ever seen in a film to date. Every scene had detailed plants and animals which translated to a believable planet.

If you go back and read my post on graphics cards, you can find out how they actually made all the models. But I just wanted to point out the massive scale of this movie. EVERYTHING in this movie had to be made using those steps. An animator had to make the wireframe, texturize it, and animate it. That means every tree, every plant, every animal, every leaf that falls, all the land, all the airplanes, EVERYTHING. Just makes you appreciate the scenic vistas that the movie threw at you every 10 minutes.

Another thing was the way Avatar was filmed. Cameron was testing a new "virtual camera" system. In past films the 3D environments were added after the filming finished. But using the new system, Cameron was able to see in real time how the actors were interacting with the environment. Another major innovation was the realistic motion capture. The actors were put into normal motion capture suits, but in addition, they wore a camera head rig. It filmed the actors facial expressions so that they could be realistically mapped onto the 3D models. As a result Avatar had some of the most realistic characters in a long time.

Avatar was a technical marvel of film. It sets the bar for how sci fi movies should look. The panoramic landscapes and massive landmarks define how an alien planet should look.

Tech Term of the Week #5: Ethernet

2009-12-12T08:35:00.000-08:00

ETHERNET CABLE!!!

ok so this weeks term is ethernet! An ethernet cable is usually what connects your router(HAHA) to your computer so you can get internet access. Like everything in computers there is a stupidly complicated name that no one uses, Ethernet is no different. Technically its called the RJ45 but ethernet is so much cooler to say.

So the first ethernet cable was made by Xerox, which was surprising to me... Anyways the first one they made could only transfer 3 megabits per second, not very impressive. The second generation, not surprisingly called 10mbit, could get up to 10 megabits, Fast Ethernet runs at 100 mbit, gigabit 1 gigabit, and at the pinnacle is 10 gigabit.

this is getting really dry so here is a picture a bunny with a pancake on its head

So just like wifi has standards ethernet has standards, too. The current standard IEE 802.3. This is basically the rule set that everything that uses ethernet has to follow.

im pretty much out of ideas at this point, expect maybe mentioning how we have a huge roll of stripped ethernet cables that we use to tie things up with pretty colors in robotics!

Tech Term of the Week #4: Java

2009-12-06T08:54:00.000-08:00

So Java is a object oriented programming language. Now I'm sure all of you have no idea what I'm saying (cept you Thomas...) right now. An object oriented lanugage uses objects, such as data lists and methods to do its thing. At this point I'm still pretty sure most of you have no clue what I'm talking about so I'm going to make a choice right now to not delve into the guts of java, but focus on its applications.

Also thanks to Goldberg for the idea.

Also I didnt realize Java had a mascot...

Duke the Java mascot

So Java was developed by Sun around 1990 (according to Wikipedia), December 1990 to be exact. Java really took off during the internet boom because the web had become a very interactive place, no longer being a stupid list of text that you read.

Now Java is known for its ability to work on all OSes. This leads me to my favorite programming joke.

"Saying Java is awesome is like saying anal sex is awesome, since it works on everyone"

So Java is a machine independent language, that means the code you write on one machine will work the same way on all other machines. How is this done? Basically the code is executed on a Java Virtual machine. This basically emulates a single platform that runs the same way on all computers. This used to be a big deal because a lot of times code that works one one machine will break on another, now using Java its as simple as downloading the right virtual machine.

Java used to be very prevalent in the nets but nowadays flash as pretty much taken over, at least on the outside. Many things still run Javascripts in the background, but all the visual stuff that the end user sees are all Flash based.

Where Java is really common is on cell phones because of the variety of cell phones there needs to be a singular language and Java fits the bill.

So yeah I could go on I guess, but talking about abstract things are boring.

oh and on a final note, our robot in robotics is going to be running Java this year!

Tech Term of the Week #3: Firewire

2009-11-27T09:24:00.000-08:00

Firewire aka IEEE 1394 interface is just Apple's evil plan to make us have a billion different cables that plug into different ports.

oooooo a cable!

so basically Apple engineers were like "HEY, HOW WE WE BE DIFFERENT AND NOT CONFORM!!!!!!!! HOW BOUT WE MAKE A NEW PORT SO PEOPLE CANT USE USB FOR EVERYTHING!!!!!!!!!!!!!!!!!" and then they made Firewire.

ok ok enough of shitting on Apple.

So basically Firewire was designed to replace USB as the standard. Basically it runs faster than USB but USB is so prevalent that Firewire is pretty much dead. Even the Macs have dropped firewire i think....

ok since thats about it for Firewire and I'm tired and Goldberg is stupid and picked a stupid topic im going to leave u with a Fun Fact list from wikipedia

IEEE 1394b is used in military aircraft. Developed for use as the data bus on the F-22 Raptor, it is also used on the F-35 Lightning II.^[28] NASA's Space Shuttle also uses IEEE 1394b to monitor debris (foam, ice) which may hit the vehicle during launch.

FireWire can be used for ad-hoc (terminals only, no routers except where a FireWire hub is used) computer networks. Specifically, RFC 2734 specifies how to run IPv4 over the FireWire interface, and RFC 3146 specifies how to run IPv6.

and it sucks

Poll for next weeks term!

2009-11-23T20:31:00.000-08:00

Vote for what I should talk about next! ---->

Also how would you guys like a special post by Josh Goldberg?

Tech Term of the Week #2: Graphics Cards

2009-11-20T14:12:00.000-08:00

ok, so since you were confused on that from your posts, i feel i should just keep on going and go through the entire innards of a computer.

A graphics card is a separate chip of sorts whos only goal is to calculate the positions of pixels on your screen. Graphics cards are sometimes referred to as video cards, because back in the day (you know like 8 years ago, psh who remembers anything from that long ago) people had to have video cards to play videos, since CPUs were not fast enough to play videos. Nowadays they are used solely to accurate graphical programs such as video games, 3d design, and more recently movie and picture editing.

so heres a picture of a desktop graphics card

as you can see its pretty much a box, but if get into the innards of the heat spreading box, you will find a bunch of magical technerds computer your video game models...

(before I go on, virtual cookie for the person that names what the name of the card above is)

ok so I lied its just more computer stuff. Basically a video card is almost like a mini computer whos only purpose is to render videos. It has its own set of memory chips (RAM, refer to previous post =D) and a processor. All the data is outputted thought either a DVI, VGA or S-video outputs...who uses svideo these days.... isn't that like 20 years old? Anyhoo this video card is connected to your motherboard(next weeks word?) through either a AGP (accelorated graphics port, old slot) or a PCI, which sadly i do not know what it stands for off the top of my head... but just take my work that it is pretty much the standard for different video cards these days.

So enough about how the card looks, how does it do its job exactly. Well the in depth explanation would probably span about 3 pages of this blog and since no one really cares, ima be my usual lazy self and simplify things as much as possible.

Lets take things one step at a time.

Video and picture rendering. Basically your graphics card loads the pixel locations for the video or pictures in its memory allowing it to be played back when necessary. Hopefully you already know that pictures are made of tiny tiny pixels (just realized my audience so i might have to explain that...crap). Each pixel needs an information on its color and its location. Now pictures are usually made up of millions of pixels that need to be displayed in the correct order to show the actual picture and now of big blob of colors like my first grade finger paints. Hmmmm I feel stupid after writing all this because after writing all this down I kinda realized that graphics cards dont have much to do with pictures and videos.... poop....

oh well moving on, rendering 3d models.

Ok now we come to the main reason we have graphics cards. Surprisingly its not to buy the most fancy ones to brag them to people(cough Dylan Terry cough). A 3d model is usually rendered by taking the data from the model file and making it on the graphics card. Think of making a 3d model like making a skyscraper or something. First you gotta build the frame. In 3d models this is the wireframe

kitty?

This wireframe makes up the frame, not surprisingly, of the model you want. Now computers use triangles to make the frame. I kinda forget/don't know why they use triangles, but i think it has to do with it being easier to manipulate. idk... If we showed this on the screen it would look like the kitty above with us seeing through it and only seeing the lines.

Next the graphics card adds textures to the traingles on the wireframe. Basically its like those color by number books that i loved as a kid.... i could never color inbetween the lines............ but i digress. This step is basically color by numbers on steroids. Your graphics card has to fill up every tiny triangle with a color and texture. After its done, you should have a 3d model of cat

awwwwwwwww cute kitty

ok great we have a cat, but things aren't that interesting if they aren't moving, unless they are dead... but thats another story. So to make motion, we has the same relationship as pictures are to video. We just render lots and lots of these single frames and play them back fast enough to trick your eyes into seeing motion. Which if i recall correctly is only 13 frames per second... kinda slow if you ask me.

This process is how all those cool Pixar animated movies are made. except those use huuuuuuuge nvidia tesla computers to render them at ridiculous high resolutions

see those? every single one is a rack of 4 Tesla GPUs with each able to put out 102 GB of data per second.... yeaaaaaaaaaaaaaaaaaaaa i want one...

ok so this is really really looooooooooooong and i wanna get back to watching community so ima end it here by saying graphics cards are cooooooooool.

Poll time

2009-11-19T19:38:00.000-08:00

So after mistakenly calling Marina not funny, she has decided to be totally serious whenever she talks to me. I don't know how I got dragged into this, but vote in the right sidebar

edit: after a short vote, results say that both of us are pretty unfunny....

Tech Term of the Week #1

2009-11-13T16:02:00.001-08:00

ok i know this is kinda early but i kinda realized that i dont wanna get up earlier than i have to ....

ok this week's word is DDR RAM! often shortened to just ram
no its not dance dance revolution, would be pretty awesome if you had a ram that could play ddr....

anyways DDR RAM stands for double data rate random access memory. This is the stuff that stores everything your computer is doing when its on. So lets go through what the name stands for. The double data rate refers to the technology called double pumping, which i think is that thing Tiger Woods does...lol... ok jokes aside, computers work by going through cycles of high voltage and low voltage, and a cycle consists of one up and down voltage. Double pumping however allowed us to use the high and low voltages of one cycle to transmit two pieces of information instead of one, thus double pumping, and that leads to double data rate, aka DDR

ok moving on to the RAM part, AHAH GET IT RAMPARTS AHAHAHAHAHAHAA IM SO FUNNY!

ok so basically you need ram because you need some kinda of storage that can read and write rly rly fast so that your cpu wont be stuck waiting for you storage decide to load and write data. Hence the name random access memory, it works well when you randomly need to read or write data. Now you might ask me, hey isn't that what my hard drive is used for? Reading and storing data? Well yes but your hard drives are painfully slow compared to your ram, even in comparison the fastest hard drive right now. So a little bit of numbers to put this into perspective.

The faster consumer hard drive right now is the WD Velociraptors hard drives
which spin at 10000 rpm. It reads at 130 MB/s and writes are 55MB/s.

the slowest version of ram DDR-200 has peak transfer rates of 1600MB/s up and down
and the faster ram, DDR3-1600 has transfer rates of 12800MB/s, aka hella fast.

ok im getting tired of writing so ima sum up ddr ddr2, and ddr3 in one sentence.

basically the differences are that the memory cells on the sucessive (is that the right word?) has double the pipelines out thus allow faster data transfer.

and thats this weeks tech term

Site

2009-11-13T16:00:00.000-08:00

Well I figured i needed a way to keep all these posts organized and to get an easy way to edit all these long ass posts, figured this would be easier.