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Cheap USB interface to connect Ham radios and other devices to the PC October 14, 2011

Posted by GuySoft in Crictor, diy, Electronics, Hamakor, ITU, linux, open source, wireless.
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Ham radio PC interface

Hi all,
As promised in my last post, I have finally finished designing and building a cheap interface to connect ham radios or any other audio device that does not share audio common ground to a PC, including a PTT interface. Price should be around $17 or 60 NIS.  The control is done using a USB interface, so unlike most ham radio hardware that uses serial connections, this one is plug and play in modern PCs. The neat thing is that it uses them same commands as a RigBlaster. So this interface works out of the box with common ham radio programs like Echolink and Svxlink. The interface should also work with soundmodem which can be used for X.25 packet digital communications, without any extra hardware (I am still trying to get this to work). This interface could also be used to connect to other devices that don’t share a common ground. For example like phone lines.

Parts you will need

  1. TTL USB Serial interface – The main part is a simple CP2102 $4 controller that can be percussed from ebay. It simulates a serial device, meaning you can still work with older pieces of software with it. Note though you need to solder a cable from the RTS pin on the board, because normally they don’t come with a pre-made pin.
  2. Audio line isolation transformer – This can be easily salvaged from any old dial-up modem. That’s how I get mine, it seems to be much easier to get them off old modems than finding them in electronics shops, plus they are so easily identifiable (just make sure not to break the contacts when you take them out, happened to me twice). If you can’t find any old dial-up modems you can get it from ebay. (more…)

Echolink Node Native on Linux with Svxlink, and a Cheap PTT Hardware Interface August 8, 2011

Posted by GuySoft in Crictor, diy, Electronics, Hamakor, ITU, linux, open source, programming, wireless.
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The Jerusalem Echolink Node

The Jerusalem Echolink Node (4Z7GAI-R)

Hey all,

I recently got my amateur HAM Radio license from the Israel ministry of communication. My call sign is 4Z7GAI.

I have been working on getting an Echolink node running on the Jerusalem repeater using Linux. Echolink is a closed proprietary software that lets you connect ham radios to one another and key them across the Internet. Luckily someone wrote a FOSS program called Svxlink, which lets you connect to the Echolink network on Linux., A remote radio control with an echolink server, svxlink-server and an Echolink graphical client, Qtel. I am going to explain in this post how to get svxlink compiled and working (compiling is the hard part). I will also giving out here an Ubuntu package for the lazy ones among you.

I will also add a small section on the physical connection to the radio, an old Icom IC-02AT from the 80s (around my age). (more…)

TEDding from the car – gPodder video Plugin for Rockbox April 7, 2011

Posted by GuySoft in Crictor, diy, Electronics, ipod, ITU, linux, open source, podcast, programming, python.
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TEDing from the car

TEDing from the car

Hey all,
After a few weeks of bouncing emails with Thomas Perl I am happy to announce that we have a working plugin for his wonderful podcast application called gPodder. With this plugin installed, any mp4 video podcast that is downloaded with gPodder is automatically converted to a format playable by rockbox MPEG player plugin. Effectively meaning seamless sync of video podcasts to any rockbox enabled device. I am specifically using the Sansa fuze player, but just changing the screen resolution at the top of the plugin should make it work with any other rockbox device, and with the right screen size. The final product for me of all this technical stuff is that I can listen to TED lectures in the car. Or using the verb was coined by my friend Uzair “TEDding” from my car.

How to Install

  • First you should have gPodder installed (available also as “apt-get install gpodder” or any other distribution install equivalent).
  • Second you will need these packages installed too:
     apt-get install python-kaa-metadata  ffmpeg python-dbus
  • Now all that is left is to copy this script to
    mkdir -p ~/.config/gpodder/hooks/
    cp rockbox_mp4_convert.py ~/.config/gpodder/hooks/
  • If your are using a different player from the Sansa Fuse, modify the first lines to your screen resolution:

    make sure to include the .0 at the end.

  • Thats it! Now each time video is download, for example from the TEDTalks Video Podcast it would be converted on arrival, and relinked as the file to be synced.

As usual, I would love to hear feedback from users and suggestions.


Using CHDK to photograph blackboards in University Courses August 5, 2010

Posted by GuySoft in Crictor, diy, Hamakor, ITU, linux, open source, programming, python.
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CHDK in University

CHDK used in university for capturing blackboards

Hi all,
During last semester I developed a set of scripts that lets me photograph pictures of the blackboards during my university courses, categorize them while I am taking them and automatically generate PDF document for each course week. Because physics equations are not the simplest things to input in to a laptop in realtime, I have developed the following method. I am writing the post because I have a feeling this tool could help people in many ways, since it did change how I study in lectures.

You can see my blackboard photographs here (and here is a simple pdf example, if you get lost in the Hebrew).

How it works in a nutshell

The Work Flow

The work flow - photograph, store, generate pdfs

During the lesson I take the photographs of the blackboard with a script I wrote for CHDK. In the script you set the course and week of the semester and this is stored per-picture on the SD card.

Bumble-B and an ADC with OpenGL make an oscilloscope February 22, 2010

Posted by GuySoft in Crictor, diy, Electronics, Hamakor, ITU, linux, open source, programming, python.
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Hi all,

During my small semester break I managed to connect my Bumble-b chip to an analog-digital converter (ADC).

With this I can read voltage changes and send the information to the computer to plot live.

Here is a demonstration video:

How its all connected


Brewing Cider December 24, 2009

Posted by GuySoft in Crictor, diy, Hamakor, Uncategorized.
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My cider (we call it Chateau la Sheffer)

Hey all,

During the semester break, I brewed alcoholic Cider (not to mix with apple juice, which is no-alcoholic). My cider has 7.2% alcohol.

Although some readers might think that making alcohol out of plain apple juice might involve black magic, its actually quite simple. The only thing it really takes is time – about 3 months total to start drinking, but if you wait 5 months, you will get something that tastes much better. Its quite fun, and one can create unique flavors.

Introducing the Bumble-b and using it to control a LED matrix October 8, 2009

Posted by GuySoft in Crictor, diy, Electronics, Hamakor, ITU, open source, programming.
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The Bumble-b

The Bumble-b

Hi all,

The past week I have been playing around with my new Bumble-b, as I mentioned in my last post. Basically what I did with it is control an LED matrix. After doing that I made it in to a USB Device! Thanks to the simple library LUFA. Now I can use a simple echo > /dev/ttyACM0 command to send a text message to the display. Meaning that I have now /dev/matrix!

In this post I hope to explain how to use the Bumble-b, a  programmable USB chip, including its own built in programmer, for just $20. I would also like to encourage people here in Israel to start playing with this, since its cheap and easy to order way to get started with amateur electronics.

Here is a quick introduction video (followed by a detail post):

bumble-bWhat is the Bumble-b?

The bumble-b is a USB programmable AVR chip with a programmer built in to it (called a breakout board). It is an AVR chip, meaning that its based on something that is widely used (the model is at90usb162). Moreover, since it has a USB connector right on it , this makes the creation of USB devices really simple. But not only USB devices alone.

Astrophotography Using Canon Camera’s Hack Development Kit August 16, 2009

Posted by GuySoft in Astronomy, Crictor, diy, Hamakor, ITU, linux, open source, programming.
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CHDK booting

Hi all,

I am going to explain here how I managed to use the Cannon open source hack development kit , known as CHDK, to photograph stars and even create neat movies of the stars motion.

It all started this Monday, I was lucky to see that there is going to be Perseids meteor shower, a day in advance. So I had time getting the code ready before it was too late. I thought I would go somewhere next to Jerusalem and photograph, but in the end, friends of mine (Shy and Anna) from the Israeli Astronomy Association, which I am part of, told me they are going down south to the dessert, far away from light pollution, to take count of the meteors for the IMO. So I joined him, and my data is also available.

Before all the technical stuff, here is a video I made that shows you what this all comes to:

Now back to CHDK, and how this was done.

What is CHDK? And how do I install it?

CHDK is a firmware addon for Cannon powershot digital cameras. It supports most of them, mine is a simple powershot A590, costs to date about 700 NIS. Moreover, since its an addon, it will not void warranty, and can’t damage your camera. It has a lot of features (including games and an e-book reader!).


How to build “cantenna”, a wave guide antenna out of a coffee can November 27, 2007

Posted by GuySoft in cantenna, Crictor, diy, Hamakor, linux, open source, wifi, wireless.
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This is really a translation of a post I wrote in Hebrew out of Linmagazine.

Here is my own DIY guide to build a waveguide antenna. This antenna will dramatically boost your wireless connection to a specific direction, enabling connectivity to great distances.



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