A few nights ago i finally got the out transferred from an old analogue pbx i have been using to an asterisk system. The one drawback of asterisk is that - to interface it to a PSTN line, you need a (sometimes rather expensive) card. Therefore i opted for the $20 cheapoo x100p. Unfortunatly this gave quite a powerful echo for the first 10 seconds of the call. The night previous to this i had just installed dahdi (the upgrade to zaptel) and nowhere on the internet could i find a guide to install oslec with dahdi. After a while of fact finding, i found a guide. Which made allot of assumtions and stuff… so  yea, i though ill give my version, of how i done it..

Here we assume you have the dahdi source sitting in /usr/src/dahdi (that is, the makefile, readme and the few folders)

Just before you install this, make sure you stop asterisk and dahdi

cd /usr/src

wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.28.tar.bz2

tar xjf linux-2.6.28.tar.bz2

mkdir /usr/src/dahdi/drivers/staging

cp -fR /usr/src/linux-2.6.28/drivers/staging/echo /usr/src/dahdi/drivers/staging

sed -i "s|#obj-m += dahdi_echocan_oslec.o|obj-m += dahdi_echocan_oslec.o|" /usr/src/dahdi/drivers/dahdi/Kbuild

sed -i "s|#obj-m += ../staging/echo/|obj-m += ../staging/echo/|" /usr/src/dahdi/drivers/dahdi/Kbuild

echo 'obj-m += echo.o' > /usr/src/dahdi/drivers/staging/echo/Kbuild

cd /usr/src/dahdi/

make

make install

The control software for the rotator is on the way. The lcd is interfaced. And im just starting work on the menu. I ran into a slight problem when i found out the AtMega8 chip from atmel that im using does on interrupt on all the I/O lines. It turns out i only have 2 external interrupts, which means im going to have to keep polling the pis to see if they’re high or not. Just makes the code a little more complex thats all.

I decided to use 10 turn pots for reading the actual position of the rotator, the chip turns the position into a 10 bit integer (0 - 1024) I just need to implement a small function to be able to calibrate the thing, and successfully convert a 10 bit number into a 0 - 360 degress coordinate. great fun.

Ill get my projects page populated soon enough.

Finally got my Avr ATMEGA8 microchip talking to a computer using putty..

The system consists of a max232 level converter to convert those magic ttl signals to those other magic rs232 ones..

After allot of arsing about the whole thing works quite well.. ok so it only turns on or off an LED… but its a good start. I’m finally getting around to learn to program these things fully. I can now finnaly get stuck into my long list of projects.

I’ll write more as it happens.

Enjoy!

- Paul

Had a qso with jason EI6GRB today. Both of us are learning, so it was a good slow contact. But was a contact none the less. My plain ttext is starting to improve now with the plaintext training. My advice to anyone going into a morse test. Dont do random, theres no point.

Thanks to all for their support. But i guess i was just pushing to hard. I flunked the test and failed. Now that the balls rolling i want to keep it rolling, so once I’m receiving plain text a bit better, ill be doing the test again!

it all reminds me how procrastination is bad…

- Paul

Ok its getting tight, im only on lesson 35 out of 40 and its getting hard to keep my accuracy up..  I may revert to slowing from the current 17wpm i am at.. hopefully the test on sunday goes well!

Enough said?

It’s been a while since I have blogged so:

[rant]

I sat in math this week, we were learning about differentiation (or so  I was told) “Finally” I said, I’m going to learn about some cool math at last.

Just to set the scene a little first.. I’m in pass (ordinary level) math, I dropped down because the Honors teacher wanted her class to be smaller and succeeded in getting this by teaching very badly, screaming at everyone, and being just generally immature, this of course was annoying enough, but I have decided to leave it rest for now.

So were learning differentiation.. I was pleased, we were finally going onto something I didn’t understand. So, the teacher began: “Now, there are 3 main rules in differentiation, numbers go to zero, Xs go to 1 and for squares, you multiply by the power and reduce the power by one.” Aha, she’s going to use a good method of teaching, we’re going to learn to use all these rules, and then she’s going to explain it and it will click very easily. So we continued doing example after example. We were taught a rule about having Xs on the bottom of fraction… This was all well and good, but about the fourth class of this I started to notice a lacking in my knowledge…I didn’t actually know what differentiation was. All I knew was “Numbers go to 0 Xs go to….etc…etc..”

The frustration i feel in this typical example is teaching methods. The analogy i always use is if you had to fix a car, you could get a service manual, and you would see pictures, and if these pictures matched up with the car you were sorted, but if this book was for a slightly different model, and the pictures looked different, you would be stumped (assuming you have no mechanical background). BUT, if you were taught exactly how a car works, the names of all the different components and how each one is constructed.. you wouldn’t need pictures, heck, you could probably get away without a book, because you would know how the car SHOULD work.

This applies directly to math, I have never been taught how a sum “works” only ever how to do it. What squares the annoyance is the fact that when you ask the teacher to explain “how it works” they look at you as if you have just asked them to recite pi to 1000 places..

Just before writing this paragraph I decided to read the wiki on the aforementioned subject, and this is what its opening paragraph: “In calculus, a branch of mathematics, the derivative is a measurement of how a function changes when the values of its inputs change. Loosely speaking, a derivative can be thought of as how much a quantity is changing at some given point.”

I have just learned more in one paragraph than i have in an entire week of math. It annoys me greatly, and if we want the overall intelligence of students to improve its something that needs to be addressed. What’s the point in going to school if all your doing is working towards one exam? Should you not be gaining a level of education that you can use when you m leave? sure, most won’t ever use differentiation again, but surely being able to understand the concept will improve your overall intellectual diversity, heck, what use is just being able to do them???

[/rant]

After some more footering, i got my AVR micro controller to display the contents of the ADC in 10bits. And now its all controlled from a 10 turn pot, this is now the first step on my quest to build the Rotator. Next im going to mess with interupts and com port communications.

as of this afternoon i am learning Morse code. I am using Fabian(DJ1YFK)s “Learn CW Online” website, it removes the need to search for and install CW trainers. After spening some time stuck on the letter R, i have progressed to E. Fabians site uses the Koch method, which seems to be going ok for me. Im going to take the next possible CW exam, and hopefully in a few months time, ill have a new call, and a cw key or two!