Is this just not a digital signal?

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I set out wanting to capture the signal transmitted from my gate opener (pictured at  the very bottom) but the results are confusing so I am attempting to document what I did.

The first thing I I did was build a basic receiver in gnu radio to do the capturing shown here.

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osmocom source: This an interface to our software defined radio (hardware)

  • sample rate: 16M  ( our hardware can effectively sample between 8 million IQ samples per second and 20M because of my initially confusing results I upped it to 16M hoping it was a resolution problem.
  • Ch0 : frequency: ( center frequency ):  300M  300mhz
  • Ch0: RF gain: 0 this this controls a rx amp built into our hardware)

QT GUI sink:  ( just a way to out put our signal in the frequency domain )frequency_domain

the brown line is peak hold using this I estimated the transmit frequency to be ~ 300.2 mhz the blue spike at 300 is a gnu radio side effect which occurs at the center frequency.

The next step I assumed would be to attempt to “tune” and demodulate the signal so I built a another flowgraph for that:reciver

 

  • File source: ( just our IQ samples stored in a file)
  • Throttle: This prevents gnu radio from sending data faster than 16Mps
  • QT GUI sink : outputs the previous graph
  • Frequency Xlating FIR FILTER ( was supposed to accomplish the fallowing) 
    • tune to our signal by downshifting captured spectrum by the difference between the center frequency and the tuning frequency
    • low pass filter the shifted signal with a cutoff of 50kHz and a transition width of 1Khz
    • decimate the outgoing data stream down to our working_samp_rate of 400kHz
    • XFF details ( how we do the above with this block)
      • Decimation:  int(samp_rate/working_samp_rate)
      • Taps: firdes.low_pass(1, samp_rate, filter_cutoff , filter_transition)
      • Center Frequency : freq-center_freq

Demodulation:( maybe this is where I went wrong?) : I am only really familiar with on off keying so  I use the so called “complex to magic” block to provide a high constant value when the carrier is present and a low ~constant value when the carrier is absent. 

The fallowing shows but the input provided to complex to mag and the output afterwards: 

final

So Looking at things in the time dimension demodulated or not I don’t see anything I would recognize as digital maybe a nice square wav? So I suspect that at least 1 of the fallowing things are true.

  1. My gate opener is broken
  2. my gate opener is not digital
  3. my gate opener does not use on off keying?
  4. Something else?

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REWORK the review

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A good friend recommended this book he’s sort of new to the working world so I guess he is reading a lot of stuff of this nature. The book is by the guys at 37signals; they are a web design firm who is well known for creating Basecamp, Backpack and campfire and most famously ruby on rails.  I wasn’t actually expecting a lot from this book, I am not into “design” and I have a deep deep hatred for ruby but I have been known to read a business or 2.

REWORK is marketed  as a sort of ‘everything you know is wrong’ Business book with the back cover reading “Most business books give you the same old advice: Write a business plan, study the competition, seek investors, yadda yadda. If you’re looking for a book like that, put this one back on the shelf.” and  “What you really need to do is stop talking and start working. This book shows you the way. You’ll learn how to be more productive, how to get exposure without breaking the bank, and tons more counter intuitive ideas that will inspire and provoke you.”

The book starts off with a narrative about starting your own business and introducing the authors own experiences. Their point of view is clear; anyone can start a business , it doesn’t take a lot of time or money thanks to modern technology. The authors go on to use their own experience to support their claims in a compelling manner , if you’re not familiar with signals they are a small company with under 20 employees who mostly work from home but do a lot of great work. The company has made millions of dollars  the authors use example from this experience to make the argument that you don’t have to have a giant company with lots of funding, or a huge number of employees or fancy offices to have a business,  you just need to get started and make things people want to use. For the most part this argument is well supported and I think it provides useful perspective in a time where many people are trying to raise money for their next startup and go public.

The book also covers topics that are useful even if you don’t wish to start a business and  think this is where the book really shines.Topics include workaholisum , meetings, marketing and staying late. REWORK makes an effort to deconstruct the uselessness of all of them in a both informative and entertaining fashion.

There are a few examples that stand out. The first that comes to mind is the topic of staying late anyone who has worked at a startup knows about the “virtues of working late”, the idea being the more hours you spend working and the less you sleep the more you you are obviously getting done and as such The standard working Hours for a startup are from 9am – 7 pm or later. Now I know in the US we all love work . But the book points out that most of the long hrs we do are spent  not working at all , just hanging out in the office, talking to coworkers and if you work in silicon valley playing a couple of games of table tennis. The reality is a lot of work can be done in 8 hrs if you use your time wisely and REWORK does a great job illustrating this. Another topic The book dives into is “marketing” now I expected the authors to throw out the concept of marketing entirely, but surprisingly the authors go on to explain that marketing is not about add buys or “ campaigns” but rather everything a company does from the quality of its products to its most basic interactions with is customers is a form of marketing and should be treated that way. They also offer other lower budget marketing ideas like blogs and providing tutorials for customers that might help to provider a deeper connection with customers that I certainly had not considered before.

I could go on and on about the various topics but honestly REWORK is not that long and I think almost everyone should read it. I recommend this book to anyone who is interested in doing great things and sharing them with the world. I think the marketing pitch is wrong, REWORK should really be marketed as more of a personal development or career development book,  It’s a short and easy read so  you shouldn’t have many excuses not to read it.

House of cards returns for season 2

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So as of midnight this morning ( thats always a funny phrase) house of cards is back ( and the torrent is available). I had mixed reactions to the first season I have always sort of felt that kevin spacey played a better supporting actor than a lead but I enjoyed it and I especially enjoyed not having to wait for 1 episode per week, so season 2 can be found at

http://torcache.net/torrent/C5E7E5D8EE41633BC86C67C85F6850658982C843.torrent?title=%5Bkickass.to%5Dhouse.of.cards.2014.s02.season.2.complete.720p.x264.aac

More Adventures in San Leandro

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One of the east bay’s best kept secrets

Previously I wrote a bit about why I think San Leandro is an awesome, but under appreciated city to live in. So today while I was out on my morning walk I decided to take some pictures

The things I like about san leandro are as fallows:

  • Its small quiet and safe – the population is still under 100k people
  • has a nice marina
  • BART – if you live in the bay area more than 10 minutes from bart you live in the wrong place !
  • Flat – This is big for me I like to go on long walks but walking up and down hills can really suck the fun out of it , Its nice to be able to walk to the  store.
  • its within 30 minutes of SF by bart or car

So here are the pics:

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Super Freakonomics, the review

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This is my first attempt at a book review, I have a feeling that as far as book reviews go this won’t be very good, but because  I have a narcissistic need to show off that I do in fact read books, I am writing it anyways. Please be warned my last attempt at a book review was during my junior  year of high school where  I shamelessly plagiarized the the character summaries  from the cliff notes ( it may have been spark notes, I can’t remember) of Moby Dick to prove the thesis that characters of Moby Dick were what made the story.

Super Freakonomics is the squeal to the Best selling Freakonomics by the economist Steven Levitt and that other guy who I can only assume is responsible for creating lighthearted narrative that made the first Freakonomicsthe easy to consume best seller that it was and is.

The Duo return to action in this version with a clear goal of being much more controversial. While the first outing of Freakonomics addresses issues including why drug dealers often live with there mothers , “which is more dangerous  a gun of a swimming pool” and ” what schoolteachers and sumo wrestlers have in common”  and provides ” surprising answers to these question. The second book takes on the likes of  Global warming, prostitution and the spared of AIDS. Another major difference from the first book is that this version states from the beginning that its goals are to ” begin a dialog” which is certainly an interesting take from a couple of guys who claim to use the rigorous  analysis of “data” ( they really like that word ) to find truth. “Truth” rarely requires a dialog… just saying.

So how is the book?  well the narrative is still very enjoyable and lighthearted and I think any one over  12 or 13 years old will find this an easy read. The Analysis is interesting and as you would expect from a book called freakanomics the conclusions reached by the authors are certainly surprising or at least they will be to most people . The downside to this version of freakanomics lies in the authors far more liberal use of data and sources. In the first book Levitt relies heavily on statistics and well accepted studies to support his ideas and reach logical conclusions. In this version the authors rely  much more on individuals and single sources to make arguments as apposed to reaching logical conclusions which is a bit of a shame as this sort of hurts the original premise that a ruthlessly analytical approach  to the world can be used to find truth.

I would certainly recommend this book for it’s entertainment value  its well written and filled with great humor. Unfortunately unlike the original this book seems to use the sort of shock value tactics that fill the pages and channels of much of modern media which is sad because the book would have sold fine on the back of the original and it does some of the content a disservice as some of the arguments come off as political nonsense. when in fact many of them are sound.

I won’t ever recommend that any one buy anything but I enjoyed this book and its  a shame that it didn’t re-inforce the use of ruthless analysis and and anti politisisum that the world so very deeply needs

please don’t call me an expert

noun
1. a person who has special skill or knowledge in some particular field; specialist; authority
 
As I get older I get reffed to as an expert more and more often. Now on a certain level I find this very flattering  ( and I really do appreciate all of the flattery I can get)  unfortunately don’t think this sort of thing helps me or any one else, in fact I think it does everyone real harm. and the fallowing is why.
In the last couple of years I have been  referred to as an expert in computer security , “Devops” and most recently Telephony. Certainly I know a lot about these things because I have spent a lot of time learning about them  and practicing them, for both work and for pleasure. The problem starts to occur when we look at the definition of an ” expert” ( at the top of this post) . Well I am a person so that part is good hmmm… maybe I am an expert ?  has a “special skill” well this is where I have my first problem. None of these skills that I have been identified for “expertise  ” are special.
I regard knowledge in these areas to be as necessary for living in the world as say the ability to drive, open a bank account or make a trip to the grocery store. “Devops” ( which no one really agrees on the meaning o anyways) is simply the practice of merging the development of software with the deployment of said software usually in the context of software as a service. Today there are literally millions of Sass products that billions of people use every day. Why wouldn’t every one want/need to have some understanding of how this is done?  The practice is so common it should ( and does) offer some real advantage to the people who know how its done and because of how common it is and how important it has become to the functioning of the world;  the knowledge on the subject is freely available in multiple languages from a huge number of easily accessible sources and practice can be accomplished from the comfort of your own home for the cost of a computer and an internet connection.  Nothing about this knowledge is special and telling people that it is simply discourages people from trying to learn about something that is easy to read about and understand and even try yourself.
Lets take a look at the ” particular field part”  this part does fit a little better but I still don’t like it especially when when you talk about expertise in Information technology or computers. In the modern world computers are seen in every profession from cab driving  to medicine.If you don’t think your Doctor should have knowledge about computer security  I hope you don’t mind your medical records being public. Because if she relies on the so called experts to protect your your records they most certainly won’t be private for long.
“authority” This one bothers me the most Certainly all fields have people who have been working in them a long time and people who are really good and on face value might be worth considering a trusted authority.But consider how many times these so called authorities have been terribly wrong. The fallowing are few of my favorite examples.

I think there is a world market for maybe five computers.

Thomas Watson, president of IBM, 1943

Newton, F= (GM¹M₂)/r  – Law of universal gravitation

I like this one a lot because it has fancy math( which lots of people believe  makes something authoritative). If you don’t know how this one ends; some patent clerk   was able to prove this wrong and in the process created the “theory of relativity” Ironically even Albert Einstein may turn out to be wrong in many ways.
At one point millions of people thought this guy would save Germany….. woops !
Being able to rely on some magical authority would be nice but in reality there is no substitute for critical thinking! And this is another problem with the idea of experts It Discourages the non experts from giving there own shot at critical thinking. I am not expert but I think I saw more than 5 computers today.
Originally I had more to say on this topic but I need to try and sleep.

Thinking about what my dad said.

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I was talking to my Dad today about various life things. Work, lifestyle etc… One thing that never occurred to me before was that his advice almost never comes with a rationale behind it. To clarify he does not have reasons for doing things a certain way he just does them that way. 

I find this noteable because I am not this way at all, I have a reason for doing everything I do, even the dumb things. It made me think though. My dad is a fairly successful guy with lots of life experience, maybe his way of going through life might at very least be easier ? if not Superior.

For example, one of his favorite things to say when asked why he does something that  is obviously unpleasant  ” is because I have to”. For years I have found this sentiment very annoying, obviously there is nothing one has to do ever( even staying alive is optional) Today however, I asked and he did qualify it by saying that usually the things he “has to do” no one else can get done for him at a price, monetarily or not that he can afford.

I think the thing to take away is that at very least I guess there is some cognitive cost that my dad is not incurring by not over thinking things? The question then becomes what are some things that are worth believing you “have to do”? in hopes of making life a little easier.

Any ideas?

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Why good hackers make good citizens

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Hacking is about more than mischief-making or political subversion. As Catherine Bracy describes in this spirited talk, it can be just as much a force for good as it is for evil. She spins through some inspiring civically-minded projects in Honolulu, Oakland and Mexico City — and makes a compelling case that we all have what it takes to get involved.