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Saturday, October 30, 2010

MS Excel Checking Bit Positions in Bytes and other stuff...

The other day I wanted to make a chart that showed all the numbers up to 255 sorted by the number of bits that are set to 1. Why I wanted to do this I can't remember but I manged to make a chart like that in MS Excel.  I also wanted to make a spreadsheet that would show me all the 1 bit differences from any 8 bit number, all the 2 bit differences, all the 3 bit differences and so on... What I'm writing about is how I went about doing that.
MS Excel pretty much sucks when it comes to dealing with binary numbers. The "=dec2bin()" doesn't work for a useful number of bits and there are no logical operators that you can use directly from Excel. Also there are no parity checking commands or functions that are built in to the spreadsheets. What I wanted to do specifically for my first chart was take a decimal number, convert it to a binary number then count the number of bits that are set to 1 in that number. After I figured out how many 1's there were in the number I wanted to put that number into a list.
For the second chart (or set of charts) that I wanted to make I needed to get a number, do a logical Exclusive Or with another number and then count the number of bits. Anyway here is a neat picture that shows what I came up with to do both of these things.
16 Bit dec2bin() and Parity in Excel

I wrote here about all this stuff before in another post that pretty much just explained how to do this but didn't have any examples of how to use it. This post will have some examples of how it all works.

Sunday, October 24, 2010

How To Make A Shop Dust Collector

Isn't it interesting that the words "blow" and "suck" both mean something is bad in today's vernacular? Coincidentally (or maybe not) things that suck also tend to blow. This is especially true for my Homemade Dust Collector! I wrote about this contraption over a year ago in my post "DIY Homemade (free) Shop Dust Collector (Disperser)" that some people have asked for more information about. It's not really that complicated and there are only a few things that you need to think about when building one so I decided to talk some more about it and make a video!! Below is a picture of most of it's parts.

You can see in the picture that it's really nothing more than a bucket with a blower motor attached to a hole in the lid. "What more could there be to it you ask?" Click below and you can find out! Try reading the original post as well for more exciting details! I'll add a few things that I may have missed in the text below.

Sunday, October 17, 2010

Number Sequences with MS Excel Visual Basic, Prime Numbers etc...

What is this post all about? I don't really know but it was fun to do and it is what I have been doing so this is what I am writing about! After all this blog is supposed to be about the things I am doing. Enough with the fancy introductions...
I really like number sequences, or more specifically integer sequences, because to me they are interesting in some mysterious way. I don't think that I am the only person that feels this way because there is a On-Line Encyclopedia Of Integer Sequences that is full of them here OEIS. Anyway I decided to write some Visual Basic scripts in Excel and play around with them. The first thing I decided to do was make a chart that has the square number sequence (OEIS sequence A000290) going down the page in a diagonal. That is the purple values below:

This square number sequence is the square of the integers... so start with 1, 2, 3, 4,... and square those and you get (1*1) = 1, (2*2) = 4, (3*3) = 9, (4*4) = 16 etc... What enormous amounts of fun you say!? What could possibly make this any better you ask?  Adding in the missing natural numbers in a way that still preserves the diagonal of squares is the first thing that comes to my mind!

Saturday, October 9, 2010

DIY Simple Car Alarm Flashing LED

Everyone on my block has a flashing light car alarm and I want one too!!! Actually there is more to it than that. I have a car alarm and a good one at that but it doesn't have the Anti-Theft flashing light. At night when I park my car someplace and I'm walking in to where ever it is I am going, all the cars seem to have that flashing light. I started to wonder if the car thieves look at those things... I imagine that if there is a parking lot full of cars and all of them except one has a light that one would be the car that gets stolen. So I decided to add a flashing LED light to my car. Will it make a difference? I don't know but it took less than an hour to make and install it so why not?
Car Alarm Flashing LED Circuit

Above is a picture of the circuit I came up with and the components I used. The trickiest part in getting it to work is finding the wires in the car to hook it up to. The circuit itself is really simple and straightforward and it only took me 20 minutes to build... and another 40 minutes to install it in the car!

Saturday, October 2, 2010

Homemade Camera Zoom Lens and Schlieren Experiment

I think I need a bigger playhouse workspace. The mirror that I use for my Schlieren photography requires that the camera be 120 or so inches from the face of the mirror. This is of course because of the focal length of the mirror and a longer one is better for Schlieren photography (so I'm not complaining) but it takes up a lot of room. Another thing that having a long focal  length does is it requires me to have to zoom in a lot to see what I am photographing.
The camera that I am using is a Fujifilm FinePix J38 that has a optical zoom and a digital zoom built in but they don't get close enough. Actually the digital zoom does get really close but the image gets so grainy that I can't use it. To zoom in as far as I need to I built a zoom lens for my digital camera from an old pair of binoculars. At first this seemed like a really easy way to go but I quickly realized how sensitive the alignment of the binocular is to the camera lens.
Homemade Camera Zoom Lens for Schlieren Photography
Above is a picture of the zoom lens setup that I built. The binocular is now a monocular because I cut one side of it off but you get the idea. I mounted the monocular on a couple of linear stages that are position adjustable with Vernier adjustments. These Vernier knobs allow me to position the monocular right in front of the camera lens. The camera and the adjustable monocular are both mounted on a linear slide that allows them both to be moved closer together and farther apart but keeps them exactly aligned while moving them.