AVRing
[ No Comments ] Posted on 12.23.09 in Electronics, Microcontrollers
Softrock is behaving well, but propagation has been poor. So naturally I’ve turned my attention elsewhere…. for now!
I’ve always been into microcontrollers and have played with the arduino line of open source prototype platforms quite a bit. The problem is, I always feel like I am not really programing the AVR atmega chips – instead there is another layer of abstraction (the arduino programming language).
I bought a few atmega168 chips a while back and a USBtinyISP programmer kit from LadyAda. I got to building the programmer which was really easy – it took about 30-40 minutes. I also followed the instructions on LadyAda’s site to get the compiler and programmer software (avrdude) working on my Mac laptop – again, very easy, at least for me.
Remarkably I found it tricky to hook up the programmer to the chip – which is surprising since the atmega chips are in circuit programmable. Evilmadscientist has a nice page up though, which explained how to connect the programmer pin outs to the chip pins. The picture below might help anyone else who is confused. LadyAda should really document this on her site!
Now, when I checked the pinout on my cable it seemed to be backwards from the one above. That is, colmns 1 and 2 were flipped. I probably installed the ribbon cable wrong on Ladyada’s programmer. Anyway, I suggest others check before programming a chip. Just check where you have 5V and ground.
#include
int main (void)
{
DDRB |= 0b00000011; // Set LED as output
TCCR1B |= (1 << CS10); // Set up timer
PORTB = 0b00000010; // turn PB1 on, turn PB0 off
uint8_t i = 0;
for (;;) {
// Check timer value in if statement, true when count matches 1/20 of a second
if (TCNT1 >= 49999) // 49999 normal -- 20 Hz flash
{
if ( i >= 10 )
{
PORTB ^= 0b00000011; // Toggle the LEDs: 0 -> 1 or 1 -> 0 through the
// xor statement
i = 0;
}
else
{
i++;
}
TCNT1 = 0;
}
}
}
Upgrades to Blog
[ No Comments ] Posted on 11.19.09 in Blog/News, CW Morse Code, SoftRock
Well things have been busy. I landed a job in Boston which means I have been busy finishing up work at my current location. Moving is annoying so I have been rethinking the amount of computer gear I have. This means I have been migrating all my web stuff onto the one machine. It’s all there now – I should say it’s all _here_ now.
I have been working on the softrock radio as well. I built the USB interface and have been making some contacts with PSK and one (poorly) attempted one on CW using a paddle through the USB interface. It all works very nicely!
Now I just need to amp up the 1 watt out from the softrock into something more like 10 watts. That would be nice…. working on that now, $$$ permitting. This might have to wait until after the move to Boston.
Softrock works!
[ 1 Comment ] Posted on 08.27.09 in Amateur Radio, Home Brew, SoftRock, Uncategorized
It works!
Below is the build, essentially done. I need to better connect audio in and out. And I need to consider if I will add the DB9 serial connector. Marvel at the beauty of the Softrock TXRX V6.3 below.
And did I mention, it works!? Below I have it operating on the 40M band – tuned to W1AW at 7047.5 kHz. The software is Rocky. Rocky has a nice “auto IQ Balance” function which I had a bit of trouble getting to work nicely with an EMU 0202 USB sound card. I had the input volumes turned up quite high which seems to be a mistake. I tuned them way down and the software corrected itself very fast after that. I have absolutely no mirror images that I can see at all. Any images would have to be down at least 50-60 dB for me not to notice them.
The inbuilt sound card in my Macbook Pro does a pretty good job as well, but the EMU 0202 is an improvement. I’ll have to take some screen shots and compare them more systematically.
I did get a chance to transmit as well. I found I could get rid of the mirror images easily with the TX IQ Balance in Rocky. The mirror image was down at least 50 db after balancing. I have no idea what power output I have. I need to work on this a little more.
Problems and Concerns:
- The EMU 0202 sound card can sample at 192 kHz, but Rocky can not work at this frequency. Annoying!
- I suck at construction. I keep getting worn joints with the audio in/out and I’m wearing out the sockets.
- I really wanted to get this to work with my ASUS 901H Netbook, but it is really too slow to work at high sampling bandwidth. Also, the standard soundcard inside the netbook is terrible. Resorting to the EMU 0202 works, but sound out is choppy at times.
- The Local Oscillator Frequency is quite strong and radiates as well. I will measure just how much is radiated compared to a CW signal and it’s mirror image, soon.
In all, I’m very happy to have this project working. It is a bit ugly in places – I need to develop of construction skills a bit – but it has been a lot of fun. I should have it cased up soon and be ready to put into operation in the field soon. I should be upgrading to general license soon too (maybe extra as well) so I will be able to use this radio alone legally soon too.
Geek VodCast
[ No Comments ] Posted on 08.16.09 in Electronics
I just came across this website by David L. Jones (I think he uses the L so he is not confused with the famous Australian Department Store). Anyway – he is a fellow Aussie – from Sydney to boot – and has a video podcast relating to all things electrical engineering.
I’ll be honest – his style is amateurish. The content, though, is largely interesting. He also speaks with a very typical (and to many weird) Australian accent, complete with bizarre inflections at the end of sentences. Yes, we Aussies do that. Its kind of a cross between being emphatic while asking a question at the same time.
Anyway I suggest checking it out – I hope he doesn’t run out of steam and keeps coming up with some interesting topics.
Blog Updated
[ No Comments ] Posted on 08.12.09 in Blog/News
Wordpress had a major flaw resulting in the ability for the admin to lose control of the blog – pretty crafty. Anyway this blog is updated, so if you are a robot and think you can wrestle the password away from me, think again 
I’ll have an update on the softrock radio soon. Receive is working nicely!
New Cover
[ No Comments ] Posted on 07.20.09 in Blog/News
I’ve selected a new theme for the blog and edited it a bit. My apologies to blinding-light.com.
SoftRock RXTX V6.3 Buiding
[ No Comments ] Posted on 07.17.09 in Amateur Radio, Home Brew, SoftRock, Soldering
I have been slowly building a SoftRock transceiver, which as it turns out is a bigger project than I thought it would be. Having said that, it has been great fun.
The Softrock family of kits are all centered around the SiLabs SI570 chip, a programmable oscillator, that is clocked at 4 times the center frequency required in order to generate I and Q (90 degree phase shifted) signals for mixing with received rf and passing onto a computer which acts as a software designed radio. This is of course the latest and greatest thing in radio and the SoftRock Kits are exploiting this technology cheaply and making it available to the hobbyist to build themselves. If you want to know more, check out the SoftRock page or read up on Software Defined Radio.
Only problem is the soldering of the chip!!! Check out the image below.
That’s right, surface mount is the go here, but not only surface mount, it is pinless! The chi is pinless!!! I have never done this before, but I have so far managed to solder the sucker in place and once under the command of a pic chip that programs its frequency in, it oscillates quite nicely (at 4 times the needed frequency).
The kit I am working on has a transmitter stage too, so it is a full transceiver. I will post more on it as I build more. I just wanted to show off my soldering of a pinless IC. Still can’t believe it works.
ARRL Field Day 2009
[ No Comments ] Posted on 07.15.09 in Amateur Radio
Ooops, I’m a little late with this. Been tinkering with this website too much and not posting enough!
Well this years ARRL Field Day was my first, and it was a blast. The purpose of Field Day is primarily to get Amateur Radio Operators away from their shacks and operate in the field, away from commercial, AC mains power. Our club, W6YRA (the Bruin Amateur Radio Club at UCLA) went up to Chilao Flats camp ground to work off battery and solar power for the duration of the event.
Camping is not complete without a fire. Here we have Neil, me, Jill and Ryan (left to right) enjoying man’s oldest past time.
Here is me logging CW contacts being made my Jacob. I (almost) copied my first call sign in CW (morse code). Still got a long way to go before I can copy CW well – but I guess field day was a great way to get in some practice.
OK, lastly, a quick shot of a rattle snake that decided to sneak up on us.
New Blog
[ No Comments ] Posted on 06.20.09 in Blog/News
OK, its up and hopefully this one will settle and take.