Computers

Endeavor: Projector

· December 19, 2018 · Content · , · No Comments

I have been half completing most of my personal projects because of school and work duties. I have recently completed one project though, and that would be a projector screen.

To start off: I bought a projector. And to clarify, I bought two. And to be technical, my friend and I both chipped in for those two projectors.

Our school, like many other schools, organizations, and businesses had a surplus auction (I think it is a continuously ongoing auction) and they sell things on there ranging from medical equipment to desk chairs, and pretty much everything in between.

I was looking through it and although I don’t have a need for furniture or medical equipment I found the electronic stuff of interest. This included the computers that they had and some projectors.

The good computers were getting auctioned up to their reasonably standard price, and the bad computers were being sold by the tens. What in the world would I have done with 20 desktop computers that would struggle to run Excel? So I passed on the computers.

But the projectors caught my eye. Good projectors cost hundreds of dollars, to have a reasonable throw range, a reasonable brightness, clarity, and quietness (believe it or not some cheap projectors hum like motors). At this auction though, they were selling classroom grade projectors for ~$50 each. So my friend and I chipped in and got two for ~$100. And it was one of the best purchases of my life.

This bad boy can project a 110 inch screen across our living room with crystal clarity. Sure, I’ll admit it doesn’t have an HDMI port, but it has a DVI port and a great resolution (nothing an HDMI to DVI adapter can’t fix). Aside from that though, this has all sorts of inputs and adjustments, and is capable of even adjusting the screen if we projected at our wall from an angle.

We projected it onto our wall for a couple of weeks, and that turned out alright, but we knew we could do better. I started thinking about how to build a projector screen. Now, I live in university owned housing so I’m not allowed to put any holes in the wall, which means I had to build a stand to our screen as well.

So I went to Home Depot (not a sponsor), bought 8 8 foot boards, construction screws, and then stopped by Walmart and bought a single bed sheet.

The construction was simple. It was to be 8 feet high, 8 feet (plus) wide, and an about 5 foot high screen. I have a power drill, I have a staple gun, and I have a living room floor which can contain this monstrosity.

Getting to work was rather easy, mainly due to the fact that I decided to use construction screws for this project (and hopefully for all future projects). If you don’t know the difference, construction screws have a hex head, are super durable, get a ton of torque, and are almost incapable of stripping. I didn’t have to drill a single guide hole for this thing, truly just plug and play.

The first night I worked on it I built the projector screen (8×5 feet) which left 2 posts dangled downwards supporting the whole thing. It sat as the interim projector screen design until I could think up a good foot design for the stand, and had enough time to construct it… This took a couple of weeks (at least 3 or 4).

Finally school ended and I had time and energy and creativity to complete it. I went back out to Home Depot bought one more 8 foot board, and had them chop it into 1 foot boards, and then went home and assembled the rest.

Here is the final result.

While assembling the feet, I also extended the screen down another foot or so, since we knew we could fit a little more of the up/down projection on an 8 foot screen. It turned out pretty well.

The total cost for this sweet home theater setup (if you exclude the price of the tools):

  • 8 foot boards * 9 ~ $27
  • Box of construction screws ~ $5
  • Projector – $50
  • Bed Sheet – $10

Total Price: ~ $92

For a 105 inch screen and the ability to fulfill 8th grade me’s dream of playing Guitar Hero on a big projector screen, this was a pretty worthwhile and fun project to complete.

Filing Away Another Post

· March 26, 2018 · Content · , , , · No Comments

Computers.

It’s the 21st century, computers are all around us, and explaining them can yield to some pretty interesting blog content.

If you have used a computer you’ve used or at the very least heard of a file, and you have probably seen many different file extensions (.png, .wav, .docx, .txt).

“What makes them different?” You might ask.

Formats.

To a computer a file looks exactly like any other file. Strings of binary, rows upon rows of 0’s and 1’s. A computer has no notion of a, b, c, unless we tell them something like 001 is a 010 is b and 100 is c. So that’s what we do. And to make it more readable we turn 8 bits (each digit in binary) into a more compressed byte (which is 2 digits in hex). This is turning 10001010 (base-2) into 8a (base-16).

This means that different files are just different ways of reading those bytes. Some files have strict formatting rules and some have no rules at all.

There are essentially two different kinds of files, even though all files are really just bytes. Human-readable and binary. Binary files are files that aren’t really intended on being read by humans, while human-readable is exactly what it sounds like.

.txt files are human-readable, if you open one up and readily convert the bytes to characters without following any formatting rules then you’ll get a file that you should be able to read.

.csv files are also human-readable but have a common formatting they have commas separating all of the variables. These are common for spreadsheets.

stuff,stuff,stuff
a,b,c
1,2,3

On the opposite end, things like .docx, the document used to hold your Microsoft Word document, is binary. It sounds confusing, but .docx is capable of holding pictures and formatting and colors and so many things that a conventional .txt couldn’t hold.

Another binary file could be something like .png which can display cool images given the proper program to read it, but also looks like this when you open it in a hex editor.Screen Shot 2018-03-26 at 3.17.23 PM.png

The right side shows what the byte values on the left look like as character, and is what it will look like if you try to open a .png in a text editor (like notepad). If you didn’t have a program to interpret it (like paint) you wouldn’t be able to get an image.

A couple of thing are worth noting here though. Notice “IHDR” on the first line?Screen Shot 2018-03-26 at 3.17.23 PM.png

That indicates to a .png reader that it is the first chunk of the .png. It has to be there and all the future data is interpreted based off of that chunk.

On the flip-side “IEND” indicates the last chunk of the .png. This lets the .png reader know to stop reading the file, since it won’t get anymore information about the image.

Screen Shot 2018-03-26 at 3.24.34 PM.png

This means that you could shove a ton of data at the end of a .png file and it won’t be read. For example: The entire Bee Movie Script.

LOL_BEE_MOVIE_SCRIPT.png

While retaining a completely normal .png image of Barry from the Bee Movie, you can actually put the entire Bee Movie Script by Script-o-rama.com on the end of it. That said, if you download that image right now it won’t have it on there, because the image reader for WordPress actually will chop it all off after only reading what is needed for the image.

If you did decide to open up a text editor and try it yourself, it would look something like this, and the image would look exactly the same, when you opened it up.

Screen Shot 2018-03-26 at 3.28.52 PM.png

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