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.
   
3. 3.5mm stereo and 2.5mm mono earphone connectors – You need one of each, PCs use a 3.5mm stereo jack and the radio’s microphone is usually a mono 2.5mm jack (consult your HT’s manual, they tend to have a schismatic for the mic). I personally like to have two 3.5mm phone plugs on each side and an adapter, so in the future I can use this interface for other things than ham radio.
4. (recommended) Isolated audio cable – Ham radios can produce a lot of interference and using isolated audio cable close to the transformer is a good idea, you won’t need more than half a meter, unless you want to put a larger distance between the radio and the PC.
5. Prototyping Perfboard – So you have what to solder the parts on.
   Now comes the difference between the two circuits, you MUST have either of the two options 6 or 7 below:
6. (option 1) Reed relay – If you manage to find this part number HE722A0510, then you will really get a simple board, with just 3 parts on it. Its also quiet compared to a normal relay.
7. (option 2) 6 pin 5V mechanical relay and two NPN 2N3904 transistors – Adding two more parts to the board and a louder relay, this would be a lesser choice, but still fully functional interface. I am putting this as an option because these parts are so common I doubt anyone would have a problem finding them.
8. (recommended) 14 pin socket – If the relay breaks, it would make it easily replaceable.
9. A 3.5mm audio splitter and a set of cheap earphones – Most sound cards today have a circuit that checks if a device is plugged in to the card, otherwise they would not play anything though it. To overcome this you can split the outgoing audio signal, connect one side to the radio interface, and the other to a set of earphones. This is not needed if you want to plug a device like an MP3 player, where there is no such check.

The Schematics

I am going to supply two schematics, the first is the one I built which uses a reed relay, which is more quiet, faster but slightly less common and costs around $3 more. The second, I built and tested on the breadboard. It uses a normal 8 pin mechanical relay and two NPN 2N3904 bipolar transistors.

The finished interface looks like this:

PTT Interface option 1 using a reed relay and the CP2102 USB to UART controller

And here is the schematic:

PTT Interface1 using a reed relay (click image to enlarge)

Note that the reed relay I used can handle the strange 3.3V to 5V connection used (pin 2 and 6 on the relay). This saves the need for an inverter, since for some reason, the TTL’s logical high is 0V and logical low is 3.3V and not the other way round (still trying to figure out if this is the spec, or the Chinese assemblers fault).

If you can’t find part number HE722A0510, then you could use two NPN 2N3904 transistors and a 8 pin mechanical relay. The NPN transistor on the left inverts the signal, while the transistor on the right amplifies the signal to 5V. This is the schematic:

PTT Interface2 using a normal 8 pin relay (click image to enlarge)

Will build ham radio interfaces for food – If you want I would build you one

I am willing to build these for people  and get paid via paypal, price is negotiable, but I don’t think I’d be willing to build this for under $55 (or 200 NIS). If I find cheaper ways to get parts, I’ll lower the price. This depends on how much call there is, and if I find a cheap way to print PCBs for this project.

I  hope this interface brings use to people.  The one I built I hope to donate to the Jerusalem Amateur Radio Society operations.

Thanks

As usual, I could not have done this alone, thanks to 4Z5UG, Eric, who helped me out with the inverting NPN circuit design, and for 4X1GM for suggesting the reed relay.

That’s it, Looking forwards to hear your thoughts on this post, 4Z7GAI wishing you 73, best regards.

The Jerusalem Echolink Node (4Z7GAI-R)

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).

Compiling Svxlink For Debian, Ubuntu packaging and Installation

My system is Debian, ubuntu needs a few extra lines and they are supplied in section number 2. If it isn’t, here is a .deb package for Ubuntu.
Note that I am checking out the qt4 branch.

1. sudo apt-get install libqt3-mt-dev libsigc++-1.2-dev tcl-dev libasound2-dev libgsm1-dev libpopt-dev subversion checkinstall
svn co https://svxlink.svn.sourceforge.net/svnroot/svxlink/branches/qt4 svxlink
cd svxlink/src
2. Only in Ubuntu (not Debian, these lines are not needed there) type these commands:

   mkdir -p async/audio/alsa
   ln -s /usr/include/sys/asoundlib.h async/audio/alsa
   ln -s /usr/include/gsm.h async/audio/
   ln -s /usr/include/popt.h echolib/

3. Then run:make
sudo checkinstall
4. Then press  2 and type “svxlink” to give the package the right name.You will have a .deb package you can install now with dpkg -i svxlink.deb

Troubleshooting:

If you are getting strange compile errors, don’t panic, its pretty normal for svxlink. Post them here, or search for them in the svxlink message archive. There are quite a few common ones.

Installing the voice files

Svnlink can speak out information on the node, for example callsigns of hams joining in or announce the time. For that you need the freely available sound files from Svxlink.
Download the the heather sound package from the svxlink sound downloads
Extract the contents (including the en_US folder inside) to the path: /usr/share/svxlinks/sounds . You may need to create the sounds folder.

Configuring Svxlink

Svxlink has many options. And detailed man pages of what they all do. The main configuration is in /etc/svxlink/svxlink.conf where you set up your callsign for the station, the RX and TX sound ports and logics. The logics let you decide if you are running a simplex repeater or a full-duplex repeater. Also you can set which modules should be used (including Echolink). Each station is unique so you will need to go over the configuration slowly and figure it out. The svxlink.conf manpage is well documented.

The echolink configuration is located at /etc/svxlink/svxlink.d/ModuleEchoLink.conf . Again, its pretty simple and there is a ModuleEchoLink.conf manpage (if you get stuck on something just comment here).

My custom hardware interface

Hardware

The circuit is simply a computer-controls relay switch. Opening and closing the audio connection between the PC sound card output, and radio mic-in.

To interface with the computer, I used my beloved Bumble-b that I posted about before. However the bumble-b is not being made anymore (we don’t know if the maker of the bumble-b, dfletcher, is dead, alive, or neither). I hope to post here later a simpler interface using a $2 usb-serial interface. But for now you can see the general idea: you could use any other computer interface that opens and closes a relay (an LPT port for example), this relay would connect the mic-in of the radio in to the speaker of the computer’s sound card, serving as a Push-To-Talk button.

The radic-mic and PC soundcard are connected to each other via an audio transformer taken off an old modem, as shown in the picture below. You can get these transformers off any old dialup modem, its easy to spot the coil on the modem board too. The transformer goes between the radio and sound card because they don’t have a common ground, if you just plug them together one would fry the other. However the radio’s speaker out and PC’s mic-in are just plugged in directly. That seems to work fine when the sound on the radio is set down low, still, you could use another transformer if you want to, it might give better results for some radios.

Custom PTT Interface for svxlink

Software

For svxlink to key using this custom interface I had to slip a few quick and dirty lines of code in to the files src/svxlink/trx/LocalTx.cpp and src/svxlink/trx/LocalTx.h .

Here is the patch. Its generally useful to look at if you have your own commands to key your custom-built PTT for svxlink. In mine I just echo to /dev/radio ‘y’ and ‘n’ in order to open and close it respectively.

Come to my new Echolink node!

I hope this helps anyone who wants to work with svxlink. You are welcome to come to my echolink node at 4Z7GAI-R that connects to the Jerusalem repeater in Israel (R1).
I connect to it now using the android app for echolink. So I can key my radio from anywhere!

Thanks

Also great thanks to strata who is on the #hamradio channel on freenode, he showed me the program and that its worth doing the painful compiling for it (it was much more painful before this blog post).

Also thanks to Geoffrey Mendelson (4X1GM). Who gave me the radios and antenna to build the repeater, and his help along the way.

Comments are welcome as usual

73 for now

Holding the x in TEDx

Hey all,

Last Saturday I was at my first TEDx event at TEDxRamallah, which took place in Bethlehem. As a TED lecture lover this was a fantastic experience for me. Moreover, this is also the first time I classified as a “Jewish” Israeli citizen (As an atheist its somewhat confusing to refer to myself as such). This does put me in an unusual position slightly different from most people there. I will try and summarize my own experience in this special event. I feel its important to for me to relay what I see to both sides that rarely see eye to eye.

I shall summarize the talks that I found interesting to me:

Salome Heusel – How TED’s strategy made TED what it is

It was interesting to hear the explanation of how TED grew to the size it is today. How the “radical openness”, even though this talk is of course not the first of its kind. strategic model adopted by TED let them grow by letting others take the TEDx logo and format to reach the huge number of conferences viewers and participants they have today. Things like opening the on-site video subtitle program that let others translate the videos and reach all literate people no matter the language.

Gisel Kordestani – “The Internet amplifies voices, some are heard for the first time.”

Gisel, director of business development in Google, talked about how the Internet amplifies people’s voices, and brings about change in the community. This talk touched me, as a technological-oriented person, I see daily how the Internet as a tool helps us build conversation and understanding bottom up. Unlike Gisel, I actually started on the technological side and reached the world changing thoughts from the opposite side.

I find it profound, that thanks to the level of communication that the Internet has given us a vast majority of people living in many countries view themselves as citizens of the world.This fact is backed up with statistics in the lecture. As citizens of the world,  it seems to me much easier to engage in conversations with our neighbors and collaborate with them.

Muhammad Khatib – Don’t listen to your Mom

One of the highlights for me in the event was meeting my friend Muhammad Khatib, who I originally met in ITU TELECOM 2008 in Thailand, indirectly setting off the chain of events that lead me to TEDxRamallah. His talk was about why there are so few Palestinian entrepreneurs, and that one of their defining characteristics is that they are obligated not to listen to their mothers, who want them to have steady jobs.

Now that I am home safe, reaching TEDxRamalla was far easier than I expected it to be; the hardest thing yet was indeed not listening to my mother, who was worried sick about me going there.

Julia Bracha – A story can re-wire your mind, and the psychology behind it

This is for me probably the best lecture in the conference, mainly because it explained in to me what I am doing today out in the A territories – I am learning new things.

Julia spoke about the movie she made called Budrus the movie is about a non-violent demonstration that occurred in the Palestinian village 7 years prior to the making of the movie. She explained why this kind of film was missed in the mainstream media at the time because it didn’t fit “the narrative at the time”, being that at this time during the second intifada Palestinians were viewed as suicide bombers, not peaceful protesters. But this was the start, she borrowed psychological terms to explain why this is happening. Our minds are wired to prefer information that supports narratives that we already know. This term is known as “confirmation bias“, the tendency to favor information that confirms their preconceptions regardless of whether the information is true or not. When this tendency is overcome, we get a situation called “cognitive dissonance“, where we actually experience physical pain caused by holding two conflicting ideas. To relief this pain we ether ignore the information, or fit it in to our logical narrative of our world view. However this did make me realize I am a sort of a masochist, coming to Bethlehem where I am likely to have new information clashing with many of the narratives I hear back home. Nonetheless, I urge myself and others not to look away from such a narrative, even though cognitive dissonance can truly be discomforting. Sadly though, due to the fact that the lecture does favor the Palestinian side, when I tried to show it to a few friends here, they mostly dismiss it at once saying it’s one sided, not reaching the cognitive dissonance that one would want. I am not sure what to do about this just yet.

Slightly too political for me – The non-soldier non-settler Israeli

This TEDx was slightly too political. Although this is expected in such a place, I do find it hard to show all of the lectures to my fellow Israelis. There seem to have not been a single lecture by a Palestinian that was purely Technological, Entertainment or Design without politics embedded in to it in some way.

At first I thought it was only me, but it seemed like quite a few people from abroad approached me saying the same thing. I would like to hear from the Palestinians in the conference what they think. .I have a feeling a lot of the one-sidedness was done unintentionally. Plus it seemed like most speakers didn’t seem to know that there were two Israeli people in the crowd.

It is my opinion that if eventually we are to reach a dialog talking about the conflict, Israelis should first see Palestinians who are not talking only about politics. We need to shake the stereotype of savage terrorists first, and only then get in to the hard talks. Similar to what I was doing in TEDxRamallah myself, where some Palestinians I met said it’s the first time they saw an Israeli who is not a soldier or a settler. I was introduced a few times with the phrase “Meet Guy, he is proof that not all Israelis are bad soldiers or settlers”. Many Israelis here might find this odd, since most Israelis are indeed not in either of those categories. This made me feel how important it is for people to see that in ether side there are normal people.

Sadly people that are not allowed to enter Israel would never see this. The same goes for Israelis who think that Palestinian are savages, especially now, when I have conversations with Israelis after the recent massacre in Itamar. it’s extremely hard to convince Israelis that most Palestinians are horrified by this as any other human being would be.

Summary

The conference was indeed engaging on many levels. Politically it was an important lesson yet an uneasy one. As time passes here in Israel it becomes harder for me to grasp where I was, and how I can explain to others how it is to be there.
The psychological barrier in our minds is unimaginably higher than the physical one. Tearing it down is far more challenging than simply going against the wall separating us, going against the pain we feel when we hear an opinion we don’t like.

This blog post is radically different than the things I usually post here. However I felt I must write this down and share, if you don’t like it, please, flame responsibly.

Shy on the left, myself next to him and and Mohammad Khatib at the far right

Bethlehem Convention Palace reception

From outside the Convention Palace, one can see Efrat settlement on top of the hill

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:

  DEFAULT_DEVICE_WIDTH = 224.0
  DEFAULT_DEVICE_HEIGHT = 176.0

  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.

TEDing from the car, thanks to a gPodder hook and Rockbox

gPoder downloading and converting

SMS Twitter Gateway logo

Hey all,

I am releasing here set of instructions and source that will enable anyone to set up a phone number, that if you SMS it, will post your massage on to your own twitter account. This service is called “Twiter SMS Gate”. The service handles multiple users, and should be easily modified to support other services like statusnet (and with a bit more code maybe even other social networks). The SMS hardware required is any cheap cellphone that can work with gammu-smsd (mine is a fake Nokia from India). Twiter SMS Gate also lets users easily register to it with their own cellphone.

I hope that people that like this idea would start hosting more SMS gates, as we create a wide network of those around the world. SMS Twitter Gate-IL , The Israeli Gate, has been running for a few weeks now and even got covered in the local media here.

The source is written in Python, which includes the phone hardware hooks, webserver, twitter client and database access.

Here is the cellphone used to run my server, just to show you how simple it is to do this, no super-expensive hardware required! (server is also my personal Linux-running PC:

Fake Nokia Cellphone acting as a dedicated SMS server

• Source is available here on GitHub, along with basic instructions on how to set it up.
• Working example of an SMS Twitter Gate in Israel
• List of working gates (one at the time of writing this)

If you have any kind of difficulty setting this up, please give me feedback, so we can make it as easy as possible.

3arabi Logo

Hi  all,

As some might have noticed, Arabic speakers on the net use a form of writing called ‘Arabic chat‘ or 3arabi, which involves using Latin characters and Hindu-Arabic numerals to write words in Arabic. I wrote a small service called 3arabi that lets you translate this Arabic chat directly to English.

Apparently there are tools to do transliteration (converting Latin letters back to Arabic), and also translation. But nothing that does them both. That is why I wrote a small script that uses Google’s transliteration service and ‘Google Translate’. This does the job, but is not perfect, however, it does actually help me understand some messages.

The source is also available in GitHub (its in python). If anyone contributes better code I’ll merge it back to the service.

• 3arabi translation website
• Here is an example of linking to a translation

Thanks to Ira Abramov for hosting the service!

Thanks to Rajesh who wrote the transliteration API though after using it I moved to the javascript google tool with his help.

Thanks Muhammad Khatib who wrote Google Translate python API and for releasing it.

Enjoy,

Guy

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 - 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.

When I get home, I can quickly clear the card using the build.py script, moving the pictures to my computer, I might be taking dozens of photos a day, so its useful to do this a few times a week. The images are automatically stored in corresponding folders (e.g. /camera/coursename/pics/week1/ ).

Once the images are in the directory structure, all that is left is to generate PDFs from each ‘week folder’. There are quite a few things taken in to account here, due to the fact that the images are resized for fast PDF rendering, to setting the temporary folder of Imagemagick (it needs a few gigs to generate the PDFs!). The final outcome is a PDF file per-course per-week. From here I will go in to the technical configuration.

What you will need

• Canon powershot camera running the CHDK software (Cannon Hack Development Kit). I use a Cannon powershot A590
• Python + bash (+ Linux)
• Imagemagick installed (the convert command)
• Free space is important (both for PDF generation and storage of your photos)

Setting up CHDK script

I will not go in to the details of installing the CHDK, I wrote about this already, and its a post I recommend you read!

Once you have CHDK running on your camera you will need to use this script for shooting pictures (copy it to /CHDK/scripts and load it).

The script lets you pick the course and week, you can edit the script to have a little abbreviations for courses. For example (line 3 in blackboard.lua):
@param c Course (0=inf,1=QM,2=ds,3=fn,4=op)

It will give you a message each time you photograph with it.
The script saves files with the images filenames to the LOGS folder on the card, containing the course ID and week number.

Screenshot of the CHDK script menu

Importing you photos from the camera automatically

Using the build.py will move all the photographs from the camera to the disk, you will need to set a few things in its header, here is how the build.py file looks:

### configuration ###</p>
<p>#path to which the camera is mounted<br />
cameraMount=&quot;/media/CANON/&quot;</p>
<p>#path were the photos should be moved to<br />
DESTDIR = &quot;/media/Elements1/University/camera/&quot;</p>
<p>#path where the photos are in the camera (you might need to change this if you took more than 1000 photos)<br />
PICDIR = cameraMount + &quot;DCIM/100CANON/&quot;</p>
<p>#the number, and hte course folder to move it to<br />
course= []<br />
course.insert(0, &quot;infi&quot;)<br />
course.insert(1,&quot;quantum1&quot;)<br />
course.insert(2,&quot;dast&quot;)<br />
course.insert(3, &quot;lab2&quot;)<br />
course.insert(4, &quot;oop&quot;)

Its pretty straight forward. The last list sets which ID number corresponds to which course.

Generating PDFs

The script to generate the PDF is called genpdf.sh, It basically scans the folder and generates the pdf files using imagemagick, it also creates a small file with the picture list, so it only generates when there is a change. Generally useful script! I recommend you set the temp folder that it uses for the generation to be somewhere on your disk (and not just /tmp), because it can take as much as 10GB sometimes to generate!
Here is the settings header:

#this temp dir is where the PDF are generated, it can reach gigabytes! so its recommended to set it to a place with space<br />
export TMPDIR=/tmp</p>
<p>#path where the images are saved<br />
PICS_DIR= /media/Elements1/University/camera

Camera setting tips – How not to blind your lecturer

If you are using this tool, here are just a few minor tips for getting a good result:

• First use the manual setting in the camera (the M option). If the course is in a closed lecture hall you can tweak the exposure time to get better resultes. As you can see I also set the picture to grayscale.
• Make sure to set the flash off! Also you can set the AF-Assist beam off (its the red light on the camera). The manual setting remembers these options, so this is useful too.
• I personally try not to photograph lecturers,  I suggest you do the same.

What courses are good for this method? – Tips for Lecturers

I found that some courses are better than others to photograph, usually if you have a tidy lecturer who doesn’t erase in the middle of calculations, then you tend to get a good result. Also there are some lectures that think that the whole lecture can be done with equations only, no text. Those lectures tend to be much harder to follow, I would really suggest that they add notes, it tends to help everyone. Even a tiny title over a calculation can really change things, students don’t always follow.

That’s it! This technique really changed how I study in university, I am sure there are ways to improve the process and the code or use this for another things. I would love to hear feedback and would be glad to assist anyone attempting this.

• Here is a package with all the scripts you need

Hashtags working in Hebrew

Hello all,

I have been using twitter quite a lot recently and to users that are using non-Latin tweets, it might have occurred that the hashtags don’t work.

So I took the time to write a greasemonkey script that does the job (for Firefox, Chrome, Webkit and others).

It will add a search link on the word, unfortunately due to a twitter bug, I had to remove the number sign (#) because twitter can’t search with it.

• The script should work with all non-Latin languages (tested Hebrew, Arabic and Chinese)
• The script does not work when the “more” button is pressed. If anyone knows how to solve that please contact me. fixed!

I hope this becomes a useful tool for people.

• Download the script here
• Userscripts.org page

I came across the need for a portable VOIP phone for windows, apparently there is no package out there for this.

So I repackaged QuteCom, a cross-platform softphone. Just adding a simple parameter did the job!

You can download the package here.

Extract it and simply run the “runme.bat” file in the folder.

The package is kindly hosted for me on Hamakor FOSS Society. There is also a wiki page with additional information about Qutecom portable there.

Cheaper Than SkypeOut!

Thanks to this package I can now call anywhere on my VOIP accounts. Where usually only skype was available, meaning I have a cheaper-than-skype providers (Curently using voipvoip.com and callcentric). I really think standard VOIP should be more out there among the people giving a healthy competition.

Would love to hear feedback!

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

The Bumble-b is connected to the MCP3204 ADC, here is the schmatic from dflecher’s site:

MCP3204 wiring schematic

Software on the Bumble-B

The pulling is done with a library written by dflecher and help from LUFA (The USB-AVR library). My source is available here I recommend you look at my original Bumble-B post on how to compile and develop.

Software on the computer

To plot I used a pyOpenGL, which is a python binding to draw graphics. I based it off one of the demo examples for pyOpenGL. I did not spend much time on it, and there is a lot to improve. Like adding a grid, more options and speeding up the incoming data. Still, this tiny script is a proof of concept.

Small basic oscilloscope showing a remote control signal

I would be glad if anyone tells me how to speed up the Bumble-b serial communication, and draw faster on PyOpenGL, since this is the current bottleneck for a faster oscilloscope.

Here are all the sources I wrote for this post:

• Source for the bumble-b driver
• Source for the pyOpenGL live plotting scope

Note: This project is also compatible with the upcoming Bumble-b2

That is all for now, I hope to find time to post during this long semester