The letters 'S'

Steve Jobs: The mystery!

noreply@blogger.com (Sami Mughal) — Fri, 20 Jan 2012 20:25:00 +0000

I present to you one of the most famous images of Steve Jobs. It always makes me wonder.

It is not the eyes and that very subtle smirk on his face. It is that hand. That hand in front of his face, which seems to be supporting his chin. I have stared at it, and wondered, and questioned it. It baffles me. I have no answer to it, but I present to you a few theories:

- He just had a zit on his chin and wanted to hide it.
- He was developing a bald patch on his chin, and wanted to hide it.
- His hand is making the motion ASIAN (desi) people make to indicate the word ‘money’.
- His hand forms a triangle, which signifies the pyramids and the all seeing eye on top of the pyramid, and hence only fuels all the conspiracy theories about his products having a single ‘i’ in front of them.
- His beard is not real, and it is a wig, and was falling off and he is trying to hold it in place.
- If you look closely, it is evident that this is not his own hand. It is somebody else’s hand. This is the only way he could allow his secret love-child to become a part of history.
- Following on the other hand theory, Steve Jobs was asleep and the hand was required to keep him up.
- He had just hurt his thumb using a hammer and had been sucking it. He only took it out for the picture.
- He was giving a thumbs up and the picture was taken a few precious moments before, but turned out so good they decided to keep it.
- He had ripped his shirt or dropped something on his shirt and was trying to hide the stain.
- He had a coffee and the seat was steaming up his glasses, so he held his hand over it to stop it from doing so.
- He was really mad at the photographer and was just forming a punch.

I leave you with these thoughts. Feel free to add some of your own.

PS. And yes, I know the Steve Jobs posts have been and gone, but here is my piece on it, which should hopefully be taken in the right spirit.

The power in Weakness

noreply@blogger.com (Sami Mughal) — Mon, 16 Jan 2012 19:16:00 +0000

Before you reject this as an oxymoron, consider the setup. Not just in Pakistan, but all over the world. Not just in the UK, not just in the US, and not just in China. Consider all the laws. Consider the society, and the laws it sticks to.
And if nothing else, consider John Grisham’s The Firm.
There is a cultural and social pressure on all of us to have a house. A family. A car. Kids. The more powerful you are, and the more ‘stable’ you get, the more weaknesses you are expected to adopt.
Focussing on the culture in Pakistan, almost everything around us is supposed to push us into adopting weaknesses.
The first rule of being a Pakistani kid is to be better than every other Pakistani Kid your parents know about.
The second, and more important rule, is to get married, have kids, and give your parents some grandkids to play with.
The third, and the most important rule, is to look after your parents.
There are other things that are added to the mix like building (yes building, not buying) a house, because that is how people role in Pakistan, having a car, and other such things.
But constantly, all the time, we are reminded how we have not fulfilled these responsibilities.
The powers that be constantly remind us to grow our weaknesses. They constantly force us to adopt them. They are the only way to happiness, ours and others.
Then there is the case of the banking systems around the world.
There is mortgage, credit cards, loans, and many other things. The false belief that you can buy things from the money that you don’t have. Once again, we are fooled and rushed into gaining weaknesses in the name of happiness and prosperity.
There are our jobs, and our careers, and there are contracts and there are signatures and there are deeds, and there are millions of things that tie us in to a hidden lock. Even passports come under this category.
Why is it that we have led ourselves to believe that our prosperity and happiness lies in weaknesses? And how are we simply allowing different forces to become powerful just by signing up to them?
Is there power in our weakness? Is THEIR power in OUR weakness?
Also published on www.borderlinegreen.com.

Plugged in, not charging!

noreply@blogger.com (Sami Mughal) — Thu, 12 Jan 2012 20:44:00 +0000

So I have this new laptop at (my new) work.

I unplugged and re-plugged the charger, as you do, and discovered that the computer stated it was plugged, but was not charging.

Curious, I looked at my options/preferences, and found nothing.

Googled, and found a lot of people complaining about it. There was also a solution to it, http://jeffreypalermo.com/blog/plugged-in-not-charging-windows-7-solution/, which I was feeling a bit too lazy to try.

Talked to our IT guy, and he talked me through a few options but nothing seemed to sort it.

A bit of experimentation, and I figured that it charged when the battery was below 90%, but did not do that when it was above 90%.

And there it was. To me, it was a design feature.

And it makes perfect sense. By disabling the charging when the battery is 90% or above, it is avoiding unnecessary charge cycles. And that actually expands the battery life.

Apparently this is how Windows 7 rolls.

Has anybody else noticed this ? What is your take on it????

Dream Diary

noreply@blogger.com (Sami Mughal) — Thu, 05 Jan 2012 11:10:00 +0000

Have been having some interesting dreams lately.

Last night it was about Gulshan-e-Iqbal park in Lahore, Pakistan. That they had built it on some height. Which meant you could see all the main attractions of Lahore from that park. There was Minar-e-Pakistan in the distance, and there was Badshahi Mosque, and there were other usual attractions that Lahore knows. Obviously this dream beats all laws of Optics and Physics.

The night before the Sienfeld cast featured. Jerry was waking up early, about 4 am , every day, because some girl he liked went grocery shopping at that hour. The dream must have been in summer because it was remarkably bright for 4am then. Then I ended up talking to Kramer, and telling him that I was the ghost of Christmas future and his future lay in writing books, so he should. He agreed in typical Kramer shudders and said that from then on, that is all he shall do.

The one the night before was a bit more spooky. A bit big brother inspired I suppose. Walking down a spooky lane, feeling of anxiety. Graffiti on walls was a picture of email inboxes. Many of them. Then I looked at mine on my phone and it somehow appeared on the walls around me. Saw two people at the end of the road, who looked ‘normal’. In fact, I was glad that there were some normal looking people on the road. I felt relief, but as I walked towards them, they turned to me and hissed, asking, ‘Why do you still do it! WHY!’. Apparently they were referring to me still using emails. As I woke up, so impressed was I that I wrote different words on a piece of paper just so I would remember to write this dream down. Now that the piece of paper has been thrown away by a clean-up act, I reckoned I might as well write this down.

Has anybody else had interesting dreams lately? Anybody want to translate the above for me?

Do me a favour…

noreply@blogger.com (Sami Mughal) — Tue, 03 Jan 2012 13:07:00 +0000

PS… Do me a favour my kind friends. Just click on the ads to the right, or above this feed if you read this on a feed.

Conducting an experiment and your help would be appreciated : )

Doctor Who meets Phantom Menace

noreply@blogger.com (Sami Mughal) — Tue, 03 Jan 2012 13:06:00 +0000

This is an absolute must – watch for any Doctor Who or Star Wars fan.

Review: Wool and the Gang

noreply@blogger.com (Sami Mughal) — Sun, 25 Dec 2011 12:18:00 +0000

This is one for those who like knitting, and those who like to be stay warm in the cold winter months. It being cold and with the holidays season running on a high, I came across Wool and the gang (http://www.woolandthegang.com), where you can buy needles, yarn, wool, knitting kits, and of course, they also sell sweaters that come with their own cosy woolly and warm comfort.

Call me what you may, but I have always looked at knitting as something I would like to try out someday. And while that ‘someday’ has not come yet, I would like to make it happen. Someday, of course! And if anybody shares this with me, they have loads of videos and help which teach you how to knit, explaining in detail how all the different knots work, going from snoods to sweaters to hoodies!

They try to promote the craft of hand-knitting in our oh-so-busy lives, trying to get people to fall in love with this art again. Being helpful they promise you the best experience possible. They deliver top quality wool, with patterns that go from plain simple to highly sophisticated.

So yeah, if you are looking to make use of your holiday time this festive season, and need to find a wool shop that caters to your knitting needs, you know where to click!

Communicating between Arduino boards using I2C, Bus Extenders, and Isolation

noreply@blogger.com (Sami Mughal) — Fri, 23 Dec 2011 09:57:00 +0000

Requirement: To communicate between two Arduino Mega boards, about 7 meters apart, sending 6 bytes of data, and receiving 2 bytes of data back from the other board, keeping the supplies and grounds for both the supplies separate.

Procedure:

The first thing to do was to establish an I2C between two Arduino boards. This was done by taking two pieces of wire (short length, about 20mm), where both the boards had the same 5V and Ground.

This was done by first sending a byte from the Master to Slave and seeing if it reaches the Slave.

In the second instance, the slave processes that data, and sends a response back to the Master.

This was then repeated by sending 6 bytes to the Master, and getting one byte back from the Slave.

In the final part of this process, the Slave sends back two bytes in reply. Surprisingly, due to the nature of the Arduino WIRE library, this is a lot more complicated than it should be, or at least as intuition lends it to be. However, more on that in detail in the implementation.

Second part of the procedure is to implement the same bus over a wire length that is 7 meters long. Because of the nature of I2C, a bus extender is required. There are many of these on the market, and a P82B715 will be used to implement this.

Third part is implementation of the Galvanic Isolation. Analog Devices produce a few of those devices, and in this implementation, an ADUM1250 will be used.

Implementing I2C between two Arduino Boards

The main purpose of setting up an I2C bus was to get two Arduino Boards to talk to each other. Upon research of various communication options available, I2C stood out as a protocol that was already available and established, as well as simple to implement. It also only requires 2 wires (SDA and SCL) that are required for communication. More information about the I2C bus can be found in the reading material at the end of this post.

The Arduino communicates on the I2C bus via already dedicated pins. On the UNO they are pins 4 and 5 for SDA and SCL, while on the Mega they are 20 and 21. For other variations, the datasheet should be checked.

As long as the SDA of one is connected to the other, and SCL of one is connected to the other, the I2C Hardware implementation is complete. In the simplest implementation, the grounds of both Arduino Boards should be shared as well.

To use the I2C bus with the Arduino, the WIRE library, which is already a part of the Arduino IDE is used.

It should be noted that for this example/explanation the Arduino IDE 1.00 is used, and future as well as past versions may vary slightly. E.g. in the Arduino 22 IDE and below, the read() and write() commands are receive() and send() instead.

In this case, two Arduino software need to be prepared, one for the Master, which will govern the I2C Operation, and one for the Slave, which will receive data when the Master sends it, and sends data back to the Master, when the Master requests it.

First thing to do is import the Wire library in both the Master and the Slave.

#include <Wire.h>

For the Master, in the setup() method, join the I2C bus:

Wire.begin(); // Join the I2C bus as Master (Address 0)

For the Slave, in the setup, the I2C bus has to be joined as a certain address. In our example, we assign it address 0x02. This address is a hexadecimal value, and can be anything between 0 and 127. Which also means up to 127 devices can be added to an I2C bus.

Wire.begin(2); // Join the I2C bus as Master (Address 2)

Then in the Master, the sending and receiving of data is implemented.

This is started by the Master declaring that it is about to send data to the specified address:

Wire.beginTransmission(2); // Transmit to device 2

Then the number of bytes that are to be sent are sent. In our case this is 6 bytes. It is easier to send them as an array of 6 bytes, which is why an array of 6 bytes was declared, and sent byte by byte.

// Transmit 6 bytes of outgoing:
Wire.write(outgoingByte[0]);
Wire.write(outgoingByte[1]);
Wire.write(outgoingByte[2]);
Wire.write(outgoingByte[3]);
Wire.write(outgoingByte[4]);
Wire.write(outgoingByte[5]);

After the operation is complete, the transmission is ended:

Wire.endTransmission();

After this operation is complete, request data from the Slave, which specifies the number of bytes required as well.

Then the data is stored into a couple of bytes using the read() command.

// Receive Data:
Wire.requestFrom(2,2);
incomingByte[0] = Wire.read();
incomingByte[1] = Wire.read();

And that is all there is to sending and receiving data via a Master.

A similar implementation is carried out in the Slave. The program specifies to call a method when it receives any data, and similarly it calls a method when it is requested to send any data.

While receiving data is the exact same as master, to send data, the outgoing information should be an array of the requested size (no. of bytes requested), where the bytes in that array have the required information.

So in the loop () method, specify which methods to call when I2C data is sent or requested:

// Call receiveEvent() when received.
Wire.onReceive(receiveEvent);

// Send Data to Master:
Wire.onRequest(sendInfo);

And the method to receive is quite simply reading the bytes in and storing the values in global variables.

void receiveEvent(int howMany){

incomingByte[0] = Wire.read();
incomingByte[1] = Wire.read();
incomingByte[2] = Wire.read();
incomingByte[3] = Wire.read();
incomingByte[4] = Wire.read();
incomingByte[5] = Wire.read();

}

And to send, a similar thing is done, but in this case, a single write command is used, where it specifies the outgoing byte, as well as the size of that byte (or the number of bytes going out in that byte array).

void sendInfo () {

Wire.write(outgoingByte, 2);

}

For some reason, the Wire library, even though it seems to allow it in the documentation, or at least does not specify this as a limitation, cannot send more than one byte package at a time. So sending two different bytes separately just does not work, and the Master receives a 255, or a -1 as a response to that. There is information on this in the reading material provided.

This completes the software implementation of the I2C bus. Other methods and code can be added as required.

As is obvious, the lines that are being used for the I2C bus cannot be used for any other purpose in the Arduino code.

Extending the I2C bus over 5 meters

While this may not mean much to many Arduino Hobbyists, the I2C bus has a capacitance limit of about 400pF. In lay man terms, this translates to the fact that most wires have a capacitance of 80pF per meter, and it is hard for an I2C bus to operate above the length of 5 meters (5 x 80 = 400pF).

So in order to operate a bus over longer lengths, an extender such as a Philips/NXP P82B715 is used.

Following is a typical circuit example of how to implement this circuit:

Image from NXP P82B715 datasheet

It should be noted that while pull-up resistors are not really required for the Arduino boards over a small distance as implemented in part one, mainly because Arduino provides its own pull-up resistance, this is required for longer lengths.

The extender chip basically serves as a current buffer. The standard I2C bus operates at 3mA, and this chip amplifies that to 30mA. What this does mean, however, is that two of these chips are required, one to push the current up to 30mA, and the other to bring it down to the 3mA level again. These chips are bi-directional so work well in this setup.

Image from the 82B715’s datasheet

The currents of 3mA and 30mA also define the values of resistance we can go up to. A value of 4.7k will use up about 1mA on the source side, so this value should not be exceeded. A value of 470 Ohms will use about 10mA on the buffered side.

The resistance values shown above can be used for the implementation of the circuit then.

While this bus has been tested up to about 11m on a shielded twisted pair Cat5e, theoretically this set up should work up to 30 meters.

With the implementation of this, the circuit should look a bit like this:

Galvanically Isolating I2C bus

This is where things get a bit more complex. There may be many reasons to galvanically isolate a bus.

A device that was used in this example was Analog Device’s ADuM1250. A typical circuit is shown below:

Image from the ADum1250 datasheet

It is quite important to add the pull-up resisters, which are defined by the standard I2C bus, so values of 4k7 Ohms on either side should work quite well.

While this setup seems to work well, it was found that adding the isolation did make the bus a lot more sensitive to errors. Changes in hardware configuration from the specified (e.g. not having the pull-up resistors, and disconnecting) meant that the Arduino would go in to a hang mode, such that it would not even reset itself despite having a Watchdog timer built in to the software. The only way to get out of this is to power it down and power it up again. The reset button on the board does not work as well.

FYI, the hang mode that I state here, can be seen on the board because the ‘L’ LED starts to flash rapidly (10Hz).

Another thing that was discovered was that adding isolation somehow meant that the working length of the bus also somehow reduces itself. However, for the current configuration it still works up to 7 meters. This does mean however, that if this is being done over shorter distances, a bus extender may still be required to help overcome this issue.

Oscilloscope Readings of an I2C Bus

It is actually not very difficult to read what data is travelling on the I2C Bus if the signals are scoped.

The SCL Signal, as expected, is a uniform pulse, with bigger spaces separating every byte.

The SDA signal has one byte that dictates the send command and then the byte(s) are sent. Then, if that is how the code works, it has one byte that sends the receive command, and then the byte(s) are received.

This also means that if the bus was disconnected, the only bytes seen will be the send and receive command but no data shall be transferred.

Some images are as follows:

Zoomed out data sent and received.

Zoomed in. The top shows SCL, which are uniform pulses, and a bigger space between bytes. The bottom shows SDA, which is quite literally a high for a 1 that is sent and a low for a 0 that is sent there. As can be seen, there are quite a few noise spikes there, but in this instance, the smaller spikes seem to get ignored and hence do not affect the communication.

Further zoomed in, focuses on a single byte.

Sources/Further Reading/Help Material:

Arduino Wire Library:

http://arduino.cc/en/Reference/Wire

Tronix Stuff I2C Part 1:

http://tronixstuff.wordpress.com/2010/10/20/tutorial-arduino-and-the-i2c-bus/

Tronix Stuff I2C Part 2:

http://tronixstuff.wordpress.com/2010/10/29/tutorial-arduino-and-the-i2c-bus-part-two/.

I2C Bus working, explanation and implementation:

http://www.gammon.com.au/forum/?id=10896

Detailed FAQ on I2C:

http://www.esacademy.com/en/library/technical-articles-and-documents/miscellaneous/i2c-bus/frequently-asked-questions/i2c-faq.html

Datasheet for P82B715 (I2C Bus Extender):

http://docs-europe.electrocomponents.com/webdocs/009a/0900766b8009a3e8.pdf

Datasheet for ADUM1250 (I2C Bus Isolator):

http://www.analog.com/static/imported-files/data_sheets/ADUM1250_1251.pdf

(Updates: 04/01/12)

I2C Master Library:

http://dsscircuits.com/articles/arduino-i2c-master-library.html

Forum Discussing this Topic:

http://arduino.cc/forum/index.php?topic=84322

Question of religion

noreply@blogger.com (Sami Mughal) — Wed, 21 Dec 2011 20:19:00 +0000

Was just reading this http://awaisaftab.blogspot.com/2011/12/monstrosities.html when the thought to write this occurred to me.

Religion is becoming quite unpopular lately. There is the issue of Crusades, the corruption and scandals among the church, there is all this up rise and violence in the world in the name of Islam, there is growing concern about Jews taking over the world’s finances, and that is only just touching it.

But what is religion? Why do we only call these belief systems religion. What about atheism? The belief that is there no belief? What about patriotism? Isn’t that also a kind of religion.

I know these things do not really count as religion, but the sort of belief religion requires, doesn’t that also apply to all these other things.

Also, since Mr Hitchin just passed away recently, I ended up watching a few of his best known debates.

Sadly, every time he was winning his argument, he was faced by someone who was bit of a sadly stupid person. The arguments were almost designed to get him to win. Mind you, he was a very clever bloke and I am sure he must have said some clever stuff and faced some clever ones in the process too.

I know Dr Zakir Naik does the same. He is obviously quite the opposite, a PhD in Religions (if I am correct, do correct me if I am wrong), a converted Muslim, who fights the cause and logic behind Islam. In his process, he goes through various belief systems, including atheism, and wins the arguments as well.

While I have seen him work with slightly better intelligence levels, at the end of the day, both of these indulge in wordplay.

I am not even sure what I am putting down right now. But it baffles me. All of this is based on wordplay.

People are supposed to be right, wrong, clever, stupid, idiotic, based on how eloquent they are.

And as per the modern trends, religion is the source of all evil, and yet the belief that religion is the source of all evil is in my head a religion of its own.

I don’t know where it leaves humanity, but we are certainly at a cross-road which does not really lead anywhere.

And as I just read on facebook, let the debate commence!

Conspiracy Theory: St George’s slaying of the dragon

noreply@blogger.com (Sami Mughal) — Mon, 19 Dec 2011 18:58:00 +0000

I present to you, a theory.

And to prove that theory, I present to you, an image. A simple image. An image of the map of UK. An image of a, or THE, dragon, that St George slayed.

Look to the left, and then look to the right. A map of UK, and a map of a slain dragon, which interestingly, looks just like the map of UK, but with Scotland cut off.

And there, lies, the theory I present.

The whole idea of St George’s slaying of the dragon represents more the idea of keeping Scotland and England separate.

Which is why the flag of England, is the St George’s flag.

PS. This is a conspiracy theory.

PPS. Artwork my own. Isn’t it amazing?

UK SNOW MAP!

noreply@blogger.com (Sami Mughal) — Fri, 16 Dec 2011 09:36:00 +0000

British people care about the weather more than they care about anything else in the world.

It is a stereotype, but it is not very far from the truth.

Which is what makes www.uksnowmap.com such a success!

It is a website that just scans Twitter, and based on what people are tweeting about the snow, puts it on a map. It is live, it is crowd-sourced, and it is the best source of information you can get just because it is so up-to-date.

All you have to do is tweet, put the hashtag #uksnow in it, put the first part of your post code in (e.g. SL1, E6, M12, etc), and give the snow a rating out of 10 ( e.g. 0/10 for none, 10/10 for heavy!).

Check it out, tweet about it, and tweet to it. Another beautiful example of why Twitter is amazing, and how nothing works better than crowd-sourcing!

Strange dream

noreply@blogger.com (Sami Mughal) — Thu, 15 Dec 2011 08:52:00 +0000

Had the strangest of dreams last night.

So apparently I had this Japanese barber I used to go get my hair cuts from.

And one day, by mistake, I end up going up the stairs or something like that. See one of the lads from the shop sitting upstairs, politely telling me I had made a mistake.

As I go down the stairs I see Snoop Dogg (YES!) walking up, with guns and what not.

And then there is a lot of firing, lots of blood, lots of explosions.

Also somehow this amazing mansion is only 2 doors down from where I live.

So yeah, I run like hell.

Somehow, because I was there, I end up on a Wanted list. I get suspended from work. Some other friends (who I do not really know in real life) also get on the wanted list.

I am just living a weird life, constantly in hiding. Avoiding everyone and anyone.

As I was waking up, a nuclear war was starting between Japan and America based on that incident.

Video showing light travelling

noreply@blogger.com (Sami Mughal) — Tue, 13 Dec 2011 18:55:00 +0000

Now while today was the day CERN gave a much anticipated statement about their progress with the discovery of Higgs Boson, this video of two MIT dudes showing speed of light videoed excites me a lot more.

Here are a couple of other links in case the video does not work:

http://www.pcworld.com/article/246141/mits_light_speed_camera_snaps_a_trillion_frames_per_second.html (PCWORLD)

http://www.nytimes.com/2011/12/13/science/speed-of-light-lingers-in-face-of-mit-media-lab-camera.html

Now while the explanations, and the physics seems to make sense, the whole idea of a video that shows light travelling is mind boggling in itself.

See, a video itself shows light bouncing off of different objects, captured frame by frame by a camera, and shown to us which we see with our eyes. Our eyes work in the same principle, where the light bouncing off of different objects forms images in our head. If we were to actually see light travelling itself, then the whole idea light reflecting off of objects and forming images in our head tends to … well… confuse me at least.

But, having said that, it is an exciting prospect.

Here is to more physics!

CERN statement about Higgs Boson (13/12/11) explained:

noreply@blogger.com (Sami Mughal) — Tue, 13 Dec 2011 18:43:00 +0000

So yesterday, we were pretty sure Higgs Bosons exist. Now are almost pretty sure they exist.

In terms of numbers… we were at 90% that they exist, now we have a 92%.

While this may seem all a bit sarcastic, this is how physics moves forward, and the Higgs Boson still promises to be the greatest thing that WILL happen to physics in the imminent future!

Excerpt from the blog being published!

noreply@blogger.com (Sami Mughal) — Fri, 09 Dec 2011 09:57:00 +0000

A German company called Cornelsen Verlag, who appear to be one of the major educational publishers in Germany, have just written to me. They are working in co-operation with a Russian publisher, producing a series of school books for Russian students, teaching them English as a foreign language. They want to use an excerpt from my blog, to be used in the topic ‘Future World’. The author preparing that topic came across this: http://www.smacula.co.uk/2008/10/works-job-description-and-3d-printers.html and thinks it would be a suitable authentic material for it. I have, of course, gladly given them the permission, and am quite pleased that something I have written would become part of not just a published book, but also serve to educate people. A proud moment for me J!

New AVATAR

noreply@blogger.com (Sami Mughal) — Wed, 07 Dec 2011 11:56:00 +0000

No, not the movie.

But yeah, thanks to some research, found out that some people use SMOOTHDRAW to draw their doodles and comics. So I downloaded it, and gave it a go. It is definitely a very user-friendly software.

My attempt at drawing something Quentin Blake inspired

Using it, I created this last night, and loved it so much did I, that I thought it shall be my new avatar. So it is on my blogger now, as well as on my twitter account (http://twitter.com/smacula).

Phase Shifted PWM from Arduino & TLC5940

noreply@blogger.com (Sami Mughal) — Wed, 07 Dec 2011 10:31:00 +0000

Phase shifting is the process of shifting signals in TIME such that signals that would have been in sync originally, occur at a time / phase after the other. For example, they may be 180 degrees out of phase, which equates 50% delay in terms of PWM duty cycle, 90 degrees out of phase, which equates a 25% delay in terms of PWM duty cycle. The reason for expressing such delays in terms of PWM duty cycles is to make the following mathematics easier, as well as explain PWM signals’ phase/time shift in terms of percentage of the signal.

Advantages of Phase-shifting:

Optics: A PWM signal means that heads shine for a small time period over a certain period of time. This can be anything up to 30% in certain cases. This means that for 70% of the time, the media sees no light. If the media, or the head, is moving, this means that certain areas of the media may only see dark spots. In case different LEDs are phase shifted over the head, different LEDs will be shining at different periods of time, which means that the head can cover a better overall area and the media has a better chance of avoiding dark spots.

Current Loading: Phase shifted PWM signals mean a distributed load on the Power Supply. If the signals are distributed in terms of when they come off and on, it means the power consumption is distributed over that period of time as well, which means there is less pressure in terms of PEAK outputs from the power supply. This can essentially mean that cheaper and smaller power supplies can be used to power the LEDs.

Disadvantages:

· There are limitations to the amount of delay that can be achieved. This is directly related to the maximum PWM that shall be attained. If a PWM of more than 50% is required as an output, than the out-of-sync approach with using 2 clocks that are out of Phase on the Arduino Mega should be used. The maximum delay is given by:

Maximum delay < 100 - Maximum PWM output required

So for a maximum PWM of say 30%, a delay less than 70% can be achieved. So a number of delays between 0% and 69% can be applied on the PWM signals.

· Direct consequence of the above is that the maximum PWM is limited.

· Using up useful PWM output pins to produce the required delay signals. (More on that when covering the application).

· Extra hardware required. (More on that in the following)

Technique used:

· TLC5940 signals are all synced on the falling edge.

· TLC5940 to produce the ‘delay’ signal. So if we want to phase shift the signal by 90 degrees, we produce a 25% delay signal. In our example, we use a 10% delay.

· Invert this signal through a NOT gate. 7414 has been used to do this. Since the signals are all in SYNC, this signal cannot be produced directly from the TLC5940 chip.

· Produce a ‘Modified PWM’ signal using the TLC5940. This signal is the original signal plus the delay. So for example, if the original signal was 30%, the modified signal will be 30 + 10 = 40%.

· This explains why the delay can never be more than the maximum PWM.

· Input this signal with the inverted delay signal into an AND gate. A 7408 has been used to do this.

· The AND gate lets the first 30% of the modified PWM get through, and stops the last 10% of the modified PWM. This means that we have achieved a delayed PWM which has the exact same value as the original PWM, but is time shifted by 10%.

The following diagram shows the flow for this technique:

The next page shows our executed example in terms of waveforms:

Porn Name!

noreply@blogger.com (Sami Mughal) — Mon, 28 Nov 2011 15:47:00 +0000

So the bank keeps asking me to enter my first pet’s name as a security question. I have never, knowingly, had a pet. So yeah, I keep failing that question. As this discussion popped up at work, a colleague duly notified me that if you don’t have a pet, you can’t have a porn name*.

I don’t think that would give me many sleepless nights. I replied back!

PS: Porn name: Your first pet, and the town you were born in. In the west this works awesome as you get something like Misty London, Joey Oxford, Rufus York.

However, I don’t think it will work that well in the east. For example, Billa Lahore, Kaloo Gujranwala, Puppoo Karachi sound more like people you’d find on a WANTED list rather than the back of THAT DVD you hide under your bed!

PPS: This post is most probably going to subject me to loads of spam! GAAAAAAH !!!!

Review: Skies Unlimited

noreply@blogger.com (Sami Mughal) — Sun, 20 Nov 2011 19:23:00 +0000

This is for the ones who have a passion for the skies. Telescopes are an essential part of the kit one must possess to look up to the heavens. The main problem one has with buying a telescope is that there is such a wide variety of choice out there, and it is very hard to decide on one. This is where Skies Unlimited come in. This is a company that was formed by amateur astronomers to help fellow hobby astronomers, and they are there to offer their collective experience with buying and using telescopes to their users. They offer a direct phone number, as well as have a retail store where anyone can walk in for some good advice as well as browse different products.

They also have an ADVICE SECTION, which focuses purely on first-time buyers. They ask you simple questions, and in answering these you can guide yourself to making a good choice about what you need to buy. They even offer advice on dual purpose-telescopes, the sort that will let you observe things like birds, and nature, as well as the skies.

They also have telescopes for sale, and when you browse the immense choice of telescopes they offer, you will see that each type of telescope comes with its own description, the advantages and disadvantages it has to offer, the value you are getting for what you pay, the way it is built, the technology it uses, etc.

They also categorize these telescopes in terms of how much you want to pay, so you can choose a price range that defines your budget and go from there.

Apart from telescopes, they also offer information on, and sell, various related things, like accessories, tripods, lenses, books, charts, microscopes, weather stations, etc. They also have a newsletter which fills in on various new products and related news and information.

The only problem I find with Skies Unlimited is that it only sells to the US, but just for the amount of information they have to offer, I think it is a great website that offers a lot of information for any body who wants to start of as an amateur astronomer, and I’d visit the website just for that, even if I won’t be able to buy any kit from them.

Review: Mini Bluetooth Keyboard

noreply@blogger.com (Sami Mughal) — Sun, 13 Nov 2011 12:25:00 +0000

The new plethora of smart phones that are taking over our lives mostly boost a button-less interface. They often boast a touch screen keyboard, which depending on how fat-fingered you are, may or may not be functional for you. There are phones out there that have a keyboard packed into them, like most Blackberries, certain Window’s based phones, or Android based phones. They all come with a couple of potential problems, either the screen is too small, or the phone is too bulky, and sometimes a bit of both.

Solution? Mini Bluetooth keyboards! These are like normal keyboards, but smaller, interface with your device using Bluetooth, normally rechargeable. They can easily slide into your trouser pocket, and can be carried around in a bag for those who have to write that important email when they are out of office, and don’t have access to their laptops.

While there is quite a range out there, I tried the following one from MobileFun(www.mobilefun.co.uk), home for phone accessories of all sorts.

http://www.mobilefun.co.uk/mini-bluetooth-multimedia-keyboard-for-ios-4-black-p25250.htm

The unit is compatible with Windows PCs, Windows Phones(6.0 upwards), Android phones (2.1 upwards), PS3, Nokia Symbian S60 devices and of course, iPhone (iOS4.0 upwards).

The device comes with a CD that contains a manual, applications for different operating systems, and instructions for them.

I tried the provided application on my Android phone, and while it installed properly, it needed to be activated online and no matter how many times I tried, it did not work.

So I tried to pair it via normal methods, and lo and behold, it just paired straight away. There was actually no need to install the application. I really should have tried that.

Tried the same with my Windows laptop, and paired straight away as well. However, I paired it back again with my phone as that was where I was going to use it.

The keyboard has a real good build quality. No CHEAP feel to it, which is something you almost always expect when you buy non-branded accessories.

The keyboard on the Android system works essentially the same as the touch keyboard. You press SHIFT and then press a letter to capitalize it, instead of pressing them together. Click SHIFT twice and you get CAPS LOCK.

It comes with two LEDs, a red one that indicates low battery, or charging, a blue one that indicates pairing mode, a pairing button, an ON / OFF button that enables you to turn it off to save battery life.

All the buttons have a good tactile feel. However, they do require pressing a bit hard. A softer feel would have helped. Essentially what that means is that touch typing is not very easy.

Another problem I have is the layout. The layout is as crammed as possible, and the letters are all left aligned instead of the standard layout where they are skewed. As a result, on the last line, ZXCVBNM, I keep pressing the key to the right of the one I want to press. I am sure this can be overcome by practise.

Another problem is that the Backspace key is next to the Space key. Similarly, another thing that requires a bit of practice.

However, because of that, it does pack in a lot more keys than most touch screen keyboards offer. Most keyboards will not have arrow keys, and I have found that scrolling through text, specially when writing a long email that goes beyond the span of a single page is a big problem. This keyboard allows one to do that with no fuss!

The one thing that has stood out so far is the battery life. I received this about two weeks ago, and I have only given it one charge. While I have not used this extensively, I have used it a fair bit, given it a good run, and so far, I have not had to recharge it once.

Pros:

Immense Battery life
Small size, highly portable. Same size as a normal Smart phone.
Extremely light at 45g.
Extra keys offer more functionality than standard keyboard.
Compatible with most things with Bluetooth capability, with no-frill pairing.
Micro-USB charging port, which is in line with the new European standard of one charger for everything.

Cons:

Buttons need to be pressed a little harder than usual.
Comes with instructions for pairing that are more complicated than required.

Verdict:

Since I am very comfortable with using my SWYPE keyboard on my Android (Samsung Galaxy S), I won’t be replacing my regular keyboard usage with this. However, this will definitely accompany me on business or holiday trips, where I may have to sit down and answer emails without me having access to a computer. Since it charges off the same port (Micro-USB) as my phone, and has an immense battery life, I don’t need to worry about power issues either.

I have to thank www.mobilefun.co.uk for sending this out to review for me. If you want phone accessories, mobile phone speakers, mobile phone docks, laptop/notebook accessories, iPod/iPhone/iPad accessories, or other mobile accessories, MobileFun is a great site to visit.

I do a dot co dot uk!

noreply@blogger.com (Sami Mughal) — Sat, 12 Nov 2011 18:38:00 +0000

Well blimey crickey and other such words.

I have only just gone and registered myself a domain called http://smacula.co.uk! However, nothing changes, if you use the old domain name (http://smacula.blogspot.com), it just brings you back to this one. Apparently there should be no loose ends, but I suppose only time will tell how well that actually works.

I am sure that means not much to anyone, but hey, I like it.

Ps, somebody has already taken http://smacula.com ! Only recently too, because I did check recently! Gutted!

Swallowing words…

noreply@blogger.com (Sami Mughal) — Thu, 10 Nov 2011 13:29:00 +0000

Don’t ask me how the conversation started, but a few days ago, we were discussing the new theories emerging that say that in about 30 years time, we shall be looking towards all the insects on our planet for nutrition.

Nobody tends to like this thought, and I heard quite a few ‘I’d rather die of starvation’ or ‘you can’t make me’.

So today one of the people involved in the discussion said to me:

You know how we were talking about eating insects and all that? Well the other day I was discussing the same while walking down the street, and as I said, Never will I do that!, a fly went straight into my mouth. Yes, I swallowed a fly as I was claiming I would never have insects as food!

Lying on LinkedIn

noreply@blogger.com (Sami Mughal) — Thu, 10 Nov 2011 13:25:00 +0000

So a very familiar name pops up on email, asking me to add me as a contact on LinkedIn. I know the name, I definitely know the name. He seems to be working in my company, his job description saying roughly what I do at my work.
And that is when I finally figured out who it was. A fairly intelligent young man who used to work about 3 tiers down from what he was claiming on LinkedIn. He left a few good months ago, and from what he told us, he had actually been given a managerial role at his new job, with perks like company car and what not.
Surely, he was lying!
As he is now.
I do believe in the mantra that you should dress and behave as the person/job profile you want to be, rather than the one you work at, but actually lying about it on LinkedIn is quite wrong.
I have not added him on LinkedIn, though I feel like sending him a message to ask what the hell is he on about.
But why lie about your 'current job'?
Surely your new job was a better lie?
Which brings me to the whole issue of LinkedIn. Do people actually check out a LinkedIn profile before they hire someone? I know profiles like Facebook, Twitter, etc. are scanned by various employers, and surely the same applies to LinkedIn.
And if, you do lie on LinkedIn, and the facts do not match up, does that not automatically disqualify an application?
Article first published as Lying on LinkedIn on Technorati.

Little Fish: You never forget your first!

noreply@blogger.com (Sami Mughal) — Thu, 03 Nov 2011 19:19:00 +0000

The label ‘you never forget your first!’ is normally used for a few select delicacies in our life. Well here is the story to my very first Little Fish session, and yes, you never do forget your first Little Fish live performance. If you don’t believe me, just check them out where ever they are performing next, and if they do not impress you, leave a nasty comment here.
So yeah, I do not remember the day, I do not remember the date. I know it was slightly chilly, and I was at George’s Jamboree. The star of the show was this band called Little Fish.

Now I am relatively new to Oxford, last week marked my 2nd year in Oxford. I had been noticing the name Little Fish appear every now and then, and how great they were. Obviously one just ignores that because every band on the planet is the best thing you ever heard. I am grateful that I was proven wrong.

So yeah. George’s Jamboree. I had missed my Drama class from earlier in the evening, but was meeting the guys there to enjoy the Jamboree. Somehow, an hour or so later, I was being a very disappointed Snow White in front of the crowd. Aah, I digress.

And so, we got to the end of the show, and George introduced Little Fish and the band.

And there I was, completely blown away by the performance of Juju and Ben.

The energy these two generate without the use of a mike is amazing, almost beyond belief. One notices how Juju’s face goes from normal to red to redder, as she squeezes each and every muscle to produce the amazing sound she possesses. She carries on, as Ben aids her with his music, and does her violin impression. The song carries on, and you think you’d stop being impressed, but it keeps getting better and better.

At the end of the show, it feels almost silly to go and tell them that they are great. One feels nervous, as one does approaching any celebrity figure. However, Juju and Ben come over, and tell me (and the drama group) how they liked our act.

And that is what Little Fish is all about. They are one with you and one with me. Many times since then, I have been amazed. I have dragged people to their performance. I have always enjoyed how every one I drag has their ‘first time’ with Little Fish. It never gets old. It brings a smile to my face, even thinking about it.

Somehow, the studio work does not equate what they do in live, but perhaps I want a bit too much. Just like one can never recreate an orchestra through digital music, one can never recreate a proper Little Fish through speakers.

You can enjoy and experience some of their finest work on their website:

http://littlefishmusic.com, and follow them on their Twitter: http://twitter.com/littlefishmusic.

Or their YouTube channel:

http://www.youtube.com/user/JujuNez

Personally I focus on their acoustic stuff, but the video of Wonderful is great too!

More importantly, this amazing band from Oxford is trying to publish a book, with a new concept where you fund your own book. The idea is simple, if they can get enough people to support them, they will print the book. Luckily they are already very near the mark but need just a bit more people to join the club. Obviously if you sign up to support them, you get things in return such as the book, vinyl, shirts, stickers, etc. Everyone does, you are not giving money away, you are getting what you pay for. But in the process, you are helping one of the greatest bands around in Oxford getting even greater!
Please do go and support them at:

http://www.unbound.co.uk/books/the-new-original-little-fish-paper-club-handbook/promote?promoter_id=5654

http://unbound.co.uk/books/the-new-original-little-fish-paper-club-handbook

As of now they only need 148 more supporters, and I am sure if you have ever heard them live, you really do not need any further convincing. If not, do check out their videos.

I am sure this band is headed to great things, and you can be the ones who loved and supported them before the world went crazy about them. Remember, you heard about them here first! They are a band who were already signed, and they dropped all that, and came back and focussed on what made them happy. I leave you with this video:

Infrared Detection via Digital Camera

noreply@blogger.com (Sami Mughal) — Wed, 02 Nov 2011 13:18:00 +0000

Infrared detection via Digital Camera

Well we all know that there is no way of detecting if our remote (for TV, DVD Player, etc.) is working or not. Main reason for this is that we CANNOT see IR. IR, or infra-red, is basically light beyond the red (and yes that is red and not dead!) wavelength, which we cannot see. However, for this reason, a lot of devices use them to communicate. So when you press a button on your remote, it emits a light of the IR type, which carries a command, for example, turn the volume up, change the channel, power off, etc., and when the receiver sees this command come through, it performs that function.

Anyway, so we cannot see IR. This means that when we press the button on the remote, we do not see anything happening, and have to wait for something to happen on the receiver, such as the TV or other device. Certain manufacturers will sometimes put a visible LED on the remote as well, such as remotes from SKY or Virgin, however these visible LEDs once again do not represent the IR coming out.

However, most of us, carry in our pockets, devices that will SEE infra-red. Most mobiles have a camera in them, and normally most of them can see IR. In fact, you can see it on the preview / view-pane without even taking a picture. The video above shows me recording what I saw coming out of one of the remotes I have, with a Samsung Galaxy S.

So yeah, if your remote doesn’t seem to be working, change the batteries, or actually test whether it is emitting anything or not. Cool party trick for all your geeks out there. Sad reality for anyone who has to perform troubleshooting.