The Infamous battery re-calibration bug in Lenovo Thinkpad

My brand new Lenovo Thinkpad is a beast and is supposed to give up to 8hrs of battery backup. But there was a weird problem. As soon as the battery remaining reached 30%, it used to drop to 6% in a second. When I looked up on google, I found out that I was not the only one facing this problem. Most of them suggested that my battery was shot and that I had to buy a new one. This is highly improbable as it is brand new. I wanted to give fixing it a try before contacting customer care. And I was successful!

Before - See the battery percentage drop from 30% to 6%

For some reason, I suspected that it was somehow TLP's fault. TLP is the best power management utility for Thinkpad in Linux. It allows you to set max charging threshold so that you will be able to connect your laptop to the plug point without worrying about over charging (among many other features it provides). I felt that it is because of this, battery calibration was getting screwed up. So I set the maximum threshold to 100%.

Open /etc/default/tlp and set following variables.

START_CHARGE_THRESH_BAT0=100

STOP_CHARGE_THRESH_BAT0=100

Then I restarted my laptop to bring this to effect. As the calibration was already offset by a great extent, the only way to fix it was to keep it charged for a long time. I kept it charging for almost a day.

After - Fixed!

 Then to test it I kept discharging it. And to my surprise, it didn't drop from 30% to 6% this time!!

So the problem was with calibration and not because the battery is broken. If you face this problem, you can try this solution once before you spend $$$ on buying a new battery.

Now that I have changed the battery threshold back to 85%, if this problem occurs again, all I have to do is follow the above steps.

Download only part of a repository in github

Sometimes you would want to download only a part of a repository in Github but you don't want to download / clone the entire repository, specially when the repo is huge or has too many other things that you are not interested in. There are many ways to do this. For example you can do a shallow clone, or you can use Github API (there is a limit on number of requests per hour)..etc. However, none of them are simple and straightforward. 

I recently found out that Github supports svn to some extent. So I tried the age old svn export to download a part of the project I was interested in. And it worked.

svn export https://github.com/<username>/<project name>/trunk/<folder path>

For example:

If you want to download only docs from Bootstrap repository,

svn export https://github.com/twbs/bootstrap/trunk/docs

Now, suppose you want to download it with a different name,

svn export https://github.com/twbs/bootstrap/trunk/docs bootstrap-docs

Material Theme for Google Blogger

Inspired by Google's Material Design principles, this generates Material themes for Google Blogger using sass preprocessor.

Fork me on Github

Here are some of the themes generated with material-blogger

Get themes

Honor Theme

Aqua Theme

Pink Ribbon Theme

Sample Widgets

Button

Search Results

Popular Widget

Widget (Aqua Theme)

Archive

To see how to use it, see this

Error 500: The template is updated in other place. Please reload the original page and retry it again

When I edited my layout in Blogger and tried to preview it, I used to get the following error:

The template is updated in other place. Please reload the original page and retry it again

Then when i tried to save the layout, I used to get this error

The server was unable to save the form at this time. Please try again

After searching a lot on google, I found out that adding mobile only widgets causes this problem.
So, I followed the following steps to fix the issue.

Go to Template -> Edit HTML

Then search for mobile="only". You might find something like this:

<b:widget id='HTML4' locked='false' mobile='only' title='Mobile ad' type='HTML'>

Change this to:

<b:widget id='HTML4' locked='false' mobile='yes' title='Mobile ad' type='HTML'>


This will solve the problem. I think google should do something regarding this problem as it is not that straightforward to fix this.

ERR_TUNNEL_CONNECTION_FAILED on mobile network on android

For the past few days, whenever I tried to access any site with HTTPS, I used to get this error.

"This webpage is not available
ERR_TUNNEL_CONNECTION_FAILED"

This used to occur only on mobile network (airtel) and not on WiFi. At first it seemed to be a problem with chrome. But the same problem was there in other browsers. After breaking my head for a while I read somewhere that android doesn't support SSL over any port other than 443 (too weird to be true). But this couldn't be the issue because https://google.com , https://twitter.com etc use 443. 

Upon investigating further, I realized that it is a very silly issue. It is because the default Access Point (Airtel Live) that came with my carrier (airtel) had a proxy that was not allowing SSL Tunneling.

After setting Proxy and Port to nothing, the problem was solved!

Celebrating the return of Dragon Ball: Kamehameha boot animation

I am sure many of you are excited about the return of DragonBall after 18 years as DragonBall Super! Although I saw the original series much after it ended, I am a great fan of it and the fact that it gave birth to a new generation of anime is just amazing. Hats off to you Akira Toriyama!

To celebrate the return of DragonBall, I made a video of me performing the classic Kamehameha attack and made it my phone's boot animation. Here is the Vine of the video I made:

.

Grab the Adobe After Effects project of this video from here.

Here is how it looks while phone is booting:


Boot animation in android comes from the file called bootanimation.zip which is at /system/media. This file essentially consists of sets of sequences of images which have to be shown one after the other. Here we need to generate bootanimation.zip with just one sequence of images (extracted from the video) which runs in a loop. As there is no tool which can do this, I wrote a simple shell script.

Here we have to generate two things.

1. Folder with sequence of images.
2. Description of bootanimation.zip, which tells what to do with the images.


After running this script,  bootanimation.zip is generated. Now move it to /system/media and set the permissions to 0644 (rw-r--r--)



Now reboot the phone and you are done!

KAAAAAAMEEEEEEEHAAAAAAMEEEEEHAAAAAAAAAAA!

Play computer games through android wear using Magneto

I recently wrote an article called "Magneto = Gyroscope + Accelerometer + Geomagnetometer" where in I explained how to use Gyroscope, Accelerometer and Geomagnetometer to map your movements to mouse movements. In this article I will show you how to use Magneto 2.0 to play computer games using your android wear or phone.

Here is a video of me playing few computer games using my android wear

How to use it?

Setup

Unfortunately, I haven't made a simple way to do this YET. And this is available only for Linux and Mac. If you wan't to give a try you will have to follow all these steps. I am assuming that you have ADT setup.

Download Magneto apk

For android wear:

1. Enable developer options on your android wear and turn on USB debugging. See this to see how to enable bluetooth debugging for your watch.
2. After you are successfully able to connect to your watch from your computer, install the apk.
   

   adb install [location to the apk]

3. You are done. Now go ahead and open it on your wear

For android phone:

1. Enable developer options on your android device and turn on USB debugging or ADB over wifi.
2. Install the apk like any other.
3. You are done. Now go ahead and open it on your device.

Linux users have to install xdotool:

Ubuntu/ Debian users

sudo apt-get install xdotool

Fedora users

sudo yum install xdotool

Arch users

sudo packman -S install xdotool

Start Magneto on computer

Download this shell script and run it.

For android wear and linux

./nav -lw

For android wear and OS X

./nav -ow

For android phone and linux

./nav -lp

For android phone and OS X

./nav -op

Calibration

Calibrate what is left, right, top and bottom.

1. Hold your device in front of the computer screen. This will be your initial position.
2. Rotate your hand to left position and click on L. So, this will mark the region beyond it as Left. Then rotate your hand to the right and click on R. This will mark the region beyond it as Right. Similarly, do the same for Top (T) and Bottom(B)
   
   
   
   
   
   
3. If you feel that you have to redo it, press RESET button and click on the letter. When the letter becomes L (capital L), redo Step 2.

Playing

See the video where I am playing Temple Run Online, Tetris and Pacman using my android wear!

Contributing

Fork me on github

There is a lot of scope for improvement. For instance, I haven't written the navigation script for windows. Pull requests are welcome.


You might have noticed the COMMAND button. It takes voice commands from the user and sends it to the computer. I will talk about that in another article.

Crontab UI: easy and safe way to manage your crontab files

Editing the plain text crontab is error prone for managing jobs, e.g., adding jobs, deleting jobs, or pausing jobs. A small mistake can easily bring down all the jobs and might cost you a lot of time. With Crontab UI, it is very easy to manage crontab.

Here are the key features of Crontab UI:

1. Easy Setup
2. Safe adding, deleting or pausing jobs. Easy to maintain hundreds of jobs.
3. Backup your crontabs.
4. Export crontab and deploy on other machines without much hassle.
5. Error log support

Fork me on Github

Setup

You have to setup crontab-ui on all the machines on which you want to manage crontab. Note that while running Crontab UI, you have to be on the same user as that of the crontab.

npm install crontab-ui
crontab-ui

Adding, deleting, pausing and resuming jobs.

Once setup Crontab UI provides you with a web interface using which you can manage all the jobs without much hassle.

Backup and restore crontab

Keep backups of your crontab in case you mess up.

Export and import crontab on multiple instances of Crontab UI.

If you want to run the same jobs on multiple machines simply export from one instance and import the same on the other. No SSH, No copy paste!

But make sure to take a backup before importing.

See when the job is going to run next.

Separate error log support for every job

These are some of the things I am planning to add in the future

1. Run jobs as different user in one place.

2. Profiling jobs.

3. Importing from existing crontab file.

Contribute

Fork Crontab UI and contribute to it. Pull requests are encouraged.

Some of the cool vim tricks and tips

I use vim everyday. So much that even to write notes I use vim!
Here are some of the awesome tricks I have come across:

1.  Suppose you have opened a file for which you don't have permission. While saving it will say "E212: Can't open file for writing". Now instead of saving this temporarily in another file and then saving in this file, you can do this:

:w !sudo tee %

2.  You can edit binary files like in hexedit 

:%!xxd

3. Easy diff between two files. Say there are two files 'a' and 'b'. To find the diff of 'a' with respect to 'b'

:vert diffs b

4. See command history

q:

5. Execute command while still in vim.

:! <command>

Here I am compiling and running cpp file without closing it.

6. Autocomplete whatever you are typing in insert mode based on the words you have typed before:

Ctrl+n

7. Directory Listing without NERDTree

:vsp %:h

8. Indenting code

=<next position>

For example, 
To indent the current line, press ==
To indent the code till next closing flower brace, press =}

Here is an example of indenting the entire code block. Place the cursor on { and then press =%

Before

Indented

9. Make searching as you type instead of after completing typing the entire thing

:set incsearch

10. Download and open source code for a given url

vim http://google.com

I usually use this to quickly view responses of my web pages.

vim http://localhost/path

I will add more in the future.

Sources:
http://vim.wikia.com/wiki/Best_Vim_Tips
What are the dark corners of Vim your mom never told you about?

A geek way to wish Happy Birthday!

There is nothing more awesome than doing regular things in a geeky way. Few days back I was wondering what would be the geekiest way to wish someone happy birthday. It should be geeky alright, but should also have regular things like cake + candles + birthday song + wishing happy birthday.

Now mixing all this with my very little knowledge in signal processing, I wrote a python code which does this:

Fork me on github

How it works?

So, here we have a virtual cake who's shade has an equalizer effect corresponding to the "happy birthday" song that is played in the background. Here, the cake has candles with flames fluttering randomly. Also, we have a fancy display of happy birthday message.

Lets see how each of it is done one by one.

Equalizer effect

The key here is to consider a sample size of frames in the audio corresponding to the part which is playing currently and display the normalized amplitudes inside the cake. First let's take a look at the amplitudes in the sound wave (stereo):

Channel L:

Channel R:

As we can see even though the audio has two channels, both are nearly the same. Hence for further calculations we will discard one of the channels. If this was not the case, we should have taken the average of both the channels. If the audio file you have taken is already mono, you don't have to worry about anything.

As there is no negative amplitude in the equalizer effect, we will make all values positive:

Now that we have the required data, we can iterate over the frames and display the amplitudes in the cake to give equalizer effect. In the current example, I am considering 1500 frames per iteration. No matter how many frames you consider in a given iteration, the total time taken to complete the iteration should be same as the time required to play the song. Hence we add a sleep after every iteration. The net sleep time+processing time should be equal to song's play time.

We can't display all the 1500 frames at a given time. Hence we take samples in that 1500 frames and averages of each sample is found. The averages are then normalized between the maximum and minimum amplitudes that can occur in the entire song. These normalized averages are then represented as a sequence of 8s (longer the sequence implies higher the amplitude). 

Walah! you have the equalizer effect.

There is a serious problem here. The time required for processing, printing on terminal and waking up from sleep are not determinable. For instance printing on xterm happens very fast whereas the mac terminal or gnome-terminal can be very slow. Hence we need to add a manual correction to the sleep time in order to stay in phase with the song which is being played.

Fluttering candle flames

If you observe the video, the candle flames can have three states:

<space> <dot> <space>

<space> <space> <dot>

<dot> <space> <space>

So basically we just have to randomly switch between these three states to get the fluttering candle flame effect.

Happy birthday text

I have used figlet to print the message. You can also display with different fonts and sizes.

Python Code

Enjoy!