Friday, 25 December 2015

ARSO info and my Winning of Virtual radio Challenge IV

Greetings for the Festive Season
Merry Christmas to all.

ARSO:
For the past few months I was busy. During these days some enthusiast HAMs and SWLs of Odisha,India came closer and unanimously decided to meet every Sunday afternoon. I am one of them.

As days passed few veteran HAMs suggested to start an association which will bring all the active inactive HAMs and SWLs Radio enthusiasts together. currently this association has a name "Amateur Radio Society of Odisha (ARSO)".

Recently ARSO Organised ASOL exam on 20th December 2015. Good number of candidates shown interest in appearing the exam. to be precise 21 candidates have filled up the form but 20 candidates could manage to come to the exam venue on specified date and time. out of these 20 candidates 12 candidates appeared for Restricted grade and 8 candidates for General grade.

ARSO has conducted extensive classes for aspirants at ARSO office for exam preparation. ARSO been instrumental for Theory(Technical and Procedure) and also for Morse practice.  I am thankful to ARSO to organize the Exam at Bhubaneswar, Odisha.

The exam was conducted at OMC Auditorium, bhubaneswar. Examiner Mr. Panja from WPC conducted the Exam with supervision of Mr. Mallik, the Monitoring Officer stationed at Bhubaneswar. Senior HAMs OM Dilip Padhi(VU2DPI), OM Sameer Ranjan Panda (VU2AOR),  OM Priti Ranjan Mekap (VU3UFX), OM Rajesh Kumar(VU3PLP) and OM Gurudutta Panda(VU3GDP) encouraged the aspirants. At the end ARSO member Mr. Pankaj Bag sponsored a grand lunch to all who are present.

In future ARSO has promised to conduct more such events. Thanks ARSO for your effort.

SWLing:
In the mean time I also have participated in a contest organised by Thomas of Swling post. Besides his Nice informative reviews on radio related subjects, he also conducts some interesting challenges. Recently he posted such a challenge, Virtual Radio challenge IV
The good news is that I am runner-up in this event and Mehdi's entry was the winner. For details please read the result page.
 


Wednesday, 27 May 2015

A Confession

In 1986 July edition of Electronics For You (EFY), a single transistor AM/MW transmitter was published. That was the time I appeared my Matriculation Exam. Results were not published, So in the vacation time (Idle mind... hence Devils workshop) I made that transmitter. The receiver was my Father's Philips Radio from 1970(all transistor). That could give me a distance of 200m I guess.
It was really an EUREKA when I heard my Voice over the radio. My Father (A science freak like me, Better I inherited Him ... ) he also jumped up and stopped his resistance for my TX adventure.
After some days of "Hello, Is my voice OK" kind of experiment, I was bitten by the bug "Can I extend the distance?" I asked every one who knows radio repairing. Most of them said "if you connect a wire from the collector of transistor to your roof top with a big wire you may get extended range". I don't know what is antenna matching and how to connect the antenna to the collector. Some one suggested that use a 100pf capacitor at the collector and connect a long wire. Which I did but results were not impressive ... it just increased few more meters of distance coverage.
I kept my eyes open and tried to collect different circuits from different fellows. Most of them never worked. Till date I collect Toy transmitter and circuits of them.
Well This is a confession of having a Transmitter without any license, and my "Toy Pirate Station" back in 1986-1988.

Sunday, 26 April 2015

Alert Earthquake in India and Nepal

Since yesterday (25th april) #earthquakes are experienced at Cuttack,Odisha; my home town. Though Odisha faces Cyclone and Flood like natural calamities every year or every other year, but earthquakes are rare. But since yesterday Odisha have witnessed several quakes some are major and some are minor.

Why Earthquakes happen?

 Yesterday few school students for the first time (perhaps) experienced earthquake so they asked me "Uncle What is earthquake? why it happens? and how it happens?" Looking at their tender age and curiosity I described them as follows.
 During break you play in the school right? "Yes uncle we do". Do you run on the corridor? "Yes uncle". Good, now tell me do you hit during running? "Yes". So when you hit someone while running what happens? I asked, "It hurts" they replied. Similarly the surface of earth is moving constantly, as you have studied in your science book core of earth is not solid, it is molten rocks. and the upper surface which is cooler is harder and it floats on the molten rock. When these floating harder rock hits other floating rock earthquake happens. Like you also shake when you hit your friend, earth's surface also shakes, this is known as earthquake.

 In Technical terms, earth surface is divided into several tectonic plates. These tectonic plates are floating on the molten core of the earth. These tectonic plated are in constant movement. So they press with each other. Due to this pressure sometimes they break or one plate dives in and other plate goes up. Himalayan mountain is created by this tectonic plate movement. Our Indian plate hits Eurasian plate and dives under it, and Himalayas is created.
[Source of the image is "http://www.tectonics.caltech.edu/"]

Is there any way to predict

No. There are several attempts made to predict earthquake but there is no way it can be predicted. But there are precursors to earthquake.
  1. Soil resistivity change
  2. change in radioactivity profile of a place
  3. sudden change in water table
  4. unusual lights and sound

Measuring Earthquakes 

 There are 2 scales but the most common now a days is Richter scale and another scale is Rosi forel scale. The former is scientific based on mathematical formula, the later is a visual scale based upon experience.
The instrument which measures earthquake magnitude is known as seismometer. 
 Seismometer operates on the principle of Inertia of rest. a simple seismometer is a simple pendulum. A simple seismometer can be made by attaching a pencil to a pendulum.

Precautions

"Earthquake doesn't kill, structure collapse kills". So there is only precautions we can take. such as
  1. Earthquake resistant construction practice
  2. If earthquake happens then quickly get out to open sky
  3. If getting out is not possible then go to a corner of the room and hold a pillow or some thing over head
  4. If that is also not possible then hide yourself under a strong table with a pillow or something.
this way one can minimize the risk and fatality though it may not be possible to escape the collapsing building.

Saturday, 18 April 2015

Installing Arduino IDE

In the last article unboxing and connecting the Arduino UNO was described. In this article how to install the IDE will be discussed. Primarily Fedora and Linux generic installation will be discussed.

Fedora

Fedora and all redhat derivatives uses yum for installation and de-installation. The easiest way to install Arduino IDE under Fedora is to issue the following command
~$ sudo yum install arduino
This command will download and install arduino package and its dependencies. After installation is complete, from terminal  bellow command should be issued.
~$ arduino
This will start the arduino IDE and flash a message box. The message box will ask to add the user to few groups Ok should be choosen here. Then it will show after the user login again changes will take effect. So just logging out and logging in is required at this point. Now the system is ready.

The arduino IDE can be started from terminal like above or it can be started from GUI Menu ( Programming -> Arduino ). Once the IDE is started, be familiarize with all the tabs and menu entries in arduino IDE. If arduino board is connected to the system via USB cable then "Tools" tab should be checked. Under "Tools" tab the "Boards" entry it should be checked and it should show the board attached or else the board should be selected manually.

 Next the "Serial Port" entry under the "Tools" tab should be checked. it should be enabled and should show the port, to which Arduino board is connected. In my case it shows "Arduino UNO" ( This is default) and "Serial Port /dev/ttyUSB0".

Hello World

Till this point it seems good. It is time to try out some adventures. for this purpose Select "File -> Examples -> basic -> blink". Corresponding sketch will be opened. Then from "Sketch" tab "Compile/Verify" should be selected. this will Compile the sketch. Next "Upload" should be selected from "Files" tab. When the uploading completes, a message will be flashed. 
Great ... The LED is blinking.

Concluding Remarks  

Here we discussed yum based installation. It is suitable for lazy and Dummies like me. But if some one want to try the harder way then please download the sources and be prepared to wait at least 3 hours until your cross compiler is ready and then manually setup everything. I am afraid of doing this adventure but this will teach how or what are the steps needed for cross compiler generation and setting up a cross compiler environment, Very Good exposure...

Blink sketch is just to check if the whole setup is working properly or not. One can try few other sketches from example too.

This concludes our second instalment in Arduino adventure. Stay tuned for the next instalment.

NOTE:  A nice document describing installation methods is available from Sparkfun here.

Thursday, 16 April 2015

Arduino UNO Adventure

Hello friends,
Priyasloka generously donated me an Arduino UNO. Though I have experience in other embedded board development, this is first time i am soiling my hand with Arduino.

This will be a series not a big chain of series. But few small parts. dealing with basics to some level of programming.

 Comparison of Arduino UNO with PIC microcontroller development board.

I have used PIC 18F4550 boards. Those board has one advantage, if a boot loader is burnt, then it is detected as a USB storage device and just copying the compiled code is sufficient. But to burn the bootloader, serial port (UART/USART) is needed. 
Arduino UNO has a serial to USB converter onboard. Which is better for beginner and dummies like me.( I hate External programmer and JTAG ) Geeeee

Getting started

I use Linux(Fedora) for casual use and also for my bread and butter.
so i decided to use my Fedora laptop for arduino adventure.

Arduino UNO has micro USB connector which is used for powering the board
as well as communicating with the board. Though UNO has a DC power supply connector.
We will get a micro USB cable which can connect to Arduino and laptop.
Mobile phone/smart phone charger cable might work for this purpose. (WARNING... I DON'T GUARANTEE IT)

We get a USB connector which connects to Arduino UNO and laptop. Bellow is the dump of messages linux throws.
Apr 16 11:36:13 localhost kernel: [ 1552.431146] usb 3-1: new full-speed USB device number 2 using uhci_hcd
Apr 16 11:36:13 localhost kernel: usb 3-1: new full-speed USB device number 2 using uhci_hcd
Apr 16 11:36:13 localhost kernel: [ 1552.583165] usb 3-1: New USB device found, idVendor=1a86, idProduct=7523
Apr 16 11:36:13 localhost kernel: [ 1552.583183] usb 3-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
Apr 16 11:36:13 localhost kernel: [ 1552.583191] usb 3-1: Product: USB2.0-Serial
Apr 16 11:36:13 localhost kernel: usb 3-1: New USB device found, idVendor=1a86, idProduct=7523
Apr 16 11:36:13 localhost kernel: usb 3-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
Apr 16 11:36:13 localhost kernel: usb 3-1: Product: USB2.0-Serial
Apr 16 11:36:14 localhost mtp-probe: checking bus 3, device 2: "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-1"
Apr 16 11:36:14 localhost mtp-probe: bus: 3, device: 2 was not an MTP device
Apr 16 11:36:15 localhost kernel: [ 1554.157815] usbcore: registered new interface driver ch341
Apr 16 11:36:15 localhost kernel: [ 1554.157850] usbserial: USB Serial support registered for ch341-uart
Apr 16 11:36:15 localhost kernel: [ 1554.157880] ch341 3-1:1.0: ch341-uart converter detected
Apr 16 11:36:15 localhost kernel: usbcore: registered new interface driver ch341
Apr 16 11:36:15 localhost kernel: usbserial: USB Serial support registered for ch341-uart
Apr 16 11:36:15 localhost kernel: ch341 3-1:1.0: ch341-uart converter detected
Apr 16 11:36:15 localhost kernel: [ 1554.170609] usb 3-1: ch341-uart converter now attached to ttyUSB0
Apr 16 11:36:15 localhost kernel: usb 3-1: ch341-uart converter now attached to ttyUSB0
 The above messages shows us that the device(UNO) has ch341 UART converter chipset, and the virtual serial port assigned to ttyUSB0.
In Unix language it will be /dev/ttyUSB0. Your board may show different USB tty so dont panic. see the messages dumped by your system.
In the Next article I will explain about Arduino IDE instalation.