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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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12 comments

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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10 comments

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…)

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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6 comments
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.
(more…)

Connecting a programmable chip to a remote Controlled Car September 11, 2009

Posted by GuySoft in Crictor, Electronics, Hamakor, ITU, linux, open source, programming, Uncategorized, wireless.
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35 comments
Car and the controller breadboard

Car and the breadboard

Hey all,

I have been playing with electronics the last few days, and I thought I might show you the outcome.

I basically took a remote controlled car, and connected it to a 16F84 programmable chip, and now I can control the car using C code.

Although I am using a car in this guide, you should be able to close and open any kind of switch. Anything under 15 volts.

For people who have don’t feel like reading all this (and also for those who do), here is an action-packed video of the outcome:

After you saw that, here is how I did this.
(more…)

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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10 comments

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!).

(more…)

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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23 comments

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.

(more…)

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