Author Archive

Great Cheap Toy for those of us over 40!

OK.. I’ve been debating about getting one of these for over a year.

USB "2.0 Megapixel" Web-cam based Microscope


I finally decided to “risk it”…
At about $30 from China on e-bay (look for “joinnew”) .. they are cheap.. but are they good enough for electronics work?

Lets see. Most claim to be 2.0 MP but like mine the are really noisy above 640×480 resolution because the sensors really are 640×480 webcam sensors. They are backlit with 8 white “high brightness” LEDs.

There are issues with the setup, and are not good enough for a true scientific instrument. But a true scientific instrument would be too much for surface mount work, anyway. So one of the “20x-200x” variants would be better for electronics than a “50x-500x” unit, anyway.

Here are the results:

Highest magnification of a offset print catalog that came in the mail:

Printing press color image at max usable resolution

BATC Digilite board– various parts shot at differing magnifications. The IC is a TSSOP, so it’s pretty small. This shows that I about have hand SMT soldering down.. this is what it should look like at magnification, BTW. (See My other blog for some tips IMHO on how to SMT solder!)

TSSOP I/Q Modulator at "medium" magnification

Chip Tantalum and leads from TSSOP at "low" magnification

Leads on TSSOP at medium magnificaion, but higher magnification than IC package picture

As you can see, it’s quite adequate for board inspection. As the magnification setting increases, the unit needs to be closer to the board. At low (20x or less) magnification the unit can be a couple of inches away from the board. It *may* be possible to actually mount and solder the part on the board when using the USB Microscope at a low magnification setting.. but I’ll have to experiment.

The units come with a poor quality stand, but I plan on getting a stand off a spring loaded arm lamp (I saw a neat one on a small little lamp at IKEA the last time I was in Chicago.. maybe if I ever get back to visit mom).. I suspect if a stand could be fabricated to keep the beast out of the way of the soldering iron, it could actually be used when soldering.. especially with the protective lens cap it comes with on. I’ll figure it out later and post somewhere.

For $30, it’s adequate for electronics use and I actually recommend it as a tool for construction. The only “rip-off” part is that it’s not really usable above 640×480– the higher “res” modes overtax the capabilities of the sensor and are very noisy. (Dont believe the 1.3 or 2.0 MP claims!) Despite this, as you can tell it’s about right for circuit board work.

I used to laugh when someone told me that “right at age 40” you get presbyopia — but I literally woke up one morning 6 months after my 40th birthday, looked down at my (out of focus through my glasses) watch and thought… “oh crap!”…It literally happened to me overnight!… Now I have to take off my glasses to do close in work. I suspect as I further deteriorate with age that it will even get worse.

This seems like an inexpensive tool to cope.

Recommended for the price. Shipping was only one week from China during the “holiday rush” time. Great deal.

The Zen of Arduino

Well, I shoulda gotten out into the detached garage this weekend and worked DX.. but the weather was nice on Thanksgiving and the day after (when I had to do family stuff thankfully) and freaking cold and windy the rest. (I can heat it but it takes some planning…)

So instead, I decided to catch up on building/hacking projects from the past and ones on a weird tangent to my current construction project the BATC DigiLite.

The past project is rebuilding my ORIGINAL 1998 Dallas Semiconductor “iButton” WS-1 One Wire weather station w/humidity and the tipping rain gauge (it’s been ten years since I had it up and running last– it took me several hours to find it!). I plan on stripping all of the one-wire garbage (sorry, it never worked reliably with any cable length at all) except for the temp sensors out of both units and embedding an AVR and running RS-485 to the units.. and connecting to an Ethernet connected Arduino to report to APRS and/or Weather Underground. My kids are interested and I’m also adding a Real Time Clock and a Barometric Pressure sensor (to the inside unit since my house isn’t pressurized) and having a fairly complete station. No PC will be required and the little 8-bit processors are misers when it comes to power usage!

I want to get my older boys interested in the systems engineering aspect and the coding and the weather station is starting to peak there interest a bit. Keeping my fingers crossed!

This is actually connected to the BATC project in that I want to use the Arduino development system and the extensive library of code instead of taking time I don’t have and writing everything from scratch on a PIC or AVR (non-Arduino). I discovered that except for the bootloader and the sometimes bloated code in some of the libraries (most are very good) that it is not that much less efficient than straight-C on the AVR’s. (The Arduino environment conceals a full open source GCC C++ complier and yup, you can write in C and C++.. you actually are even under the “sketch” environment– but they conceal that well to beginners.) Yes they are small, and slow.. but at $2.50-$6 a pop for DIP IC’s that you can hack together in a hurry.

Here is a picture of some of the AVR based toys I’ve bought and put together over the years. The “real” Arduino shields are recent.. for prototyping your own stuff they suck (since one header isn’t on 0.1″ centers.. DUH!).. but since they are a standard certain modules are cheap (at least the non-Italian “bad labor condition” clones from China) and readily available. You can put together relatively inexpensively and quickly since most of the core code can be borrowed from libraries.

Some AVR based "Arduino" toys-- Arduino 2009 clone with a Nootropic Designs Video Experimenter's Shield, a Sanguino board, an Ethernet module, a Adafruit Proto shield on top of a Clone W5100 Ethernet/SD card shield, a "Boarduino" board with a humidity/temp sensor DHT-22 on it, and a DS1307 Adafruit RTC board attached.. and a homemade video/audio out and a e-bay "DFRobot" LCD Shield 16x2 -- "Unknown" proto card at bottom will be a 5V to 3.3V bidirectional 8-bit I/O board with a 3.3V regulator on it for prototyping.

In relearning the coding, I wrote a lot of odd stuff. Here is an example of a ATMega644 (in an Sanguino PCB) doing a bunch of stuff.. talking to a LCD (via the library in 4-bit mode) and shifting data to a 74HC595 driving the LED’s in a row.. reading from a Dallas (yes, one-wire) Temperature Sensor (those are great units if not parasite powered!) with two debounced switches… doing math for the PLL synth (the numbers in the left bottom corner).. Here is a video:

Sanguino board doing all sorts of stuff

Anyway.. I am going to use the ShiftOut function on the Arduino to program the "Ultram Technologies" PLL board (That I bought preset to 1255 MHz) for the DigiLite LO on the DVB-S modulator. I was going to use that Arduino 2009 / "DFRobot" (clone) LCD Shield to do a GUI. But most of the time the little AVR will be idle. So sad. So I came across the Nootropic Designs Video Experimenters Shield and I thought… really since the BATC project needs the real time MPEG-2 chip in the Hauppage PVR-150 board.. I might as well also do a callsign overlay.

Since the Arduino 2009 has a FTDI chip on it.. it has USB to Serial functionality on it. I can poll the UART at the Vertical Blanking interval and if it receives a PLL tune command, that can be sent to the PLL and displayed (for a short time?!?) on the Video overlay as well. For now, the video overlay shows a callsign message and the system timer in ms for debugging.

Here’s a shot of that too:

Arduino/Nootropic Designs Video Experimenter Shield Overlay Example Video

The video callsign overlay is done with this "sketch":

#include <TVout.h>
#include <fontALL.d>


#define W 136
#define H 104
TVout tv;
char s[32];
unsigned int n = 0;
int index = 0;
int messageLen = 34;
char message[] = "...W0FMS Digital Amateur Television";
char saveChar;
void setup() {
tv.begin(NTSC, W, H);
initOverlay();
tv.select_font(font6x8);
tv.fill(0);
}
// Initialize ATMega registers for video overlay capability.
// Must be called after tv.begin().
void initOverlay() {
TCCR1A = 0;
// Enable timer1. ICES0 is set to 0 for falling edge detection on input capture pin.
TCCR1B = _BV(CS10);

// Enable input capture interrupt
TIMSK1 |= _BV(ICIE1);

// Enable external interrupt INT0 on pin 2 with falling edge.
EIMSK = _BV(INT0);
EICRA = _BV(ISC11);
}


// Required to reset the scan line when the vertical sync occurs
ISR(INT0_vect) {
display.scanLine = 0;
}


void loop() {
saveChar = message[21];
message[21] = '\0';


for(int x=6;x>=0;x--) {
if (x<6) {
tv.delay_frame(3);
}
tv.print(0, 92, " ");
tv.print(x, 92, message);
}
message[21] = saveChar;
saveChar = message[0];
for (int x=0; x<messageLen; x++)
message[x] = message[x+1];


message[messageLen] = saveChar;


sprintf(s, "%dms ", millis());
tv.print(0, 0, s);
}

Assuming that you’ve downloaded the Enhanced TVOut Library into the \arduino\libraries directory.. the code above is how simple something like this can be with Arduino and the libraries. This compiles to less than 10K or 1/3 of the ATMega328P (on the Arduino 2009, or 1/6 of the ATMega644 on the Sanguino).

This is why I like Arduino. It took me less than an hour to build the shield and write the example code. I am not easily impressed and even that isn’t that impressive.. but the Closed Captioning decoder example is impressive. It works really well.. and is so simple really for what it is.

I know that hopefully some day the TV input portion of the BATC project will go from SD analog to SD/HD full digital and a little hack like this won’t be appropriate anymore. But I’ve had a blast with it and I really hope I can leverage it into a learning experience for the kids also.

Pick up a few of these Arduino gadgets (now you can buy them at Radio Shack if you are in a hurry– and want to pay 3x the clone price from e-bay/China) and give it a try– it’s quick fun experimentation and I can now see the ZEN.

73, Fred W0FMS

DigiLite Update and Soapbox

Again, this is going to be a shorter version of my blogger ‘blog at http://w0fms.blogspot.com where I intend on having more random thoughts and technical detail than I post here! 🙂

I’ve purchased parts (in the US– all from Mouser for lowest overall cost except for the Analog Devices AD8346ARUZ Modulator IC– which they don’t carry) for the British Amateur Radio Club’s DigiLite “poor man’s” DVB-S SCPC modulator unit.

Almost complete BATC DigiLite DVB-S modulator board. All that is still needed is a MMIC amplifier be added after the QPSK modulator is properly adjusted with the external PLL Oscillator I am still awaiting from Israel.

The unit, as you may remember from my last post, uses an older analog Hauppage PVR-150, 250, 350, 500 and/or probably PVR-USB2 MPEG2 hardware encoder to set fixed constant bit rate (CBR) video and MP2 type CBR audio in a program stream format. This is translated to Transport Stream (TS) format for over the air transmission, Channel, EPG, and other needed DVB-S specific information is also multiplexed by the BATC software which is then sent to a DSPic33 that optionally adds the FEC (particularly at rate 1/2) and randomizes (to take out DC components because RF is inherently AC coupled!) the data– and then forms I/Q data with some pre-distortion with some tricks.. it’s filtered in a atypical way through an ANALOG LC Nyquist filter.. otherwise unfiltered PSK has infinite bandwidth! In commercial products a DSP typically would do this with a digital filter and a DAC. Finally the AD8346 does the I/Q phase shifting and that is the directly at frequency modulated DVB-S.

The LO is generated by a good e-bay find– a PLL L-band Oscillator that you can get from Ultram Tech in Israel custom programmed to one frequency. (I intend on reprogramming the unit with an Arduino [AVR ATMEGA part] board in the future– the chip’s dividers are programmed with SPI.) I have not received the board yet and didn’t want to disassemble and hack the 1152 MHz oscillator I previously bought about two years ago from Israel.

What the software and serializer firmware doesn’t do, thankfully, is care about the type of video that is in the MPEG-2 stream. I verified that tonight. The designers in the UK thought that NTSC would be fine.. and it seems to be.

Here is a video of the DigiLite “doing it’s thing” with rate 2222K video and 128K audio at a bandwidth of 3 MHz- 3MSym/S at 1/2 FEC QPSK. The video was set at NTSC D1 720×480 4:3 and I toyed with the settings until we were absolutely maxed out and were at close to zero null packets. Over the air, about 100K slower video might be a better choice. At 2112K, the null packets averaged 4.5%.. so somewhere in between these settings is about right for NTSC at 3MSym/s QPSK. This proves the digital part of the system out! We are close!

YouTube video of the BATC DigiLite running NTSC!

This is cool.. 1/2 the bandwidth and better quality than most Amateur TV. You’d think it was a no brainer for 70cm to replace 6-8 MHz AM TV? Well it is.. but in my not so humble opinion it’s not legal to run.

—SOAPBOX—
Part 97 defines that a digital phone or image (important definition) signal is legal if it uses the same or less bandwidth than the equivalent analog signal.

DVB-S and other digital standards definitely do. Unfortunately, from commercial license grants researched, I note that ATSC is C7W emission type and DVB-S/S2/C/T is G7W. Image is defined to EXCLUDE “7W” emissions. C7W and G7W are specifically defined as “multiplexed data” in another part of the rules– actually in reference to RTTY in the typical early 1980’s wording of those rules. So because DVB-S is “data” by part 97 definition, the 56K baud/100KHz BW rule applies at 70cm. In my not-so-humble-opinion it is not legal to run DVB-S nor ATSC (?!?) at 70cm because of these antiquated and wrong rules. But it is legal at 33cm and above as wideband data.

There are several who disagree with me on this. But for their definition to be valid technically by the Part 97 rules as they stand ATSC and or DVB-S would have to be G2F (DVB-S) or C2F (ATSC). By the Emissions Designator system that would also imply no audio channel. F2F is what SSTV is and I believe the “image” definition for FM/PM/PSK was specifically written with HF SSTV in mind! NO COMMERCIAL license grant (I found) has it defined that way! I can’t run 70cm DVB-S because I interpret the rules as above. Anyone who disagrees with me and wants to run it is fine with me. Wish you the best and I’m all for you! Likely the FCC nor the ARRL would do a thing to you as they shouldn’t!

What this really means is that the digital rules in US ham radio need fixing in a big way! We need to get rid of all the protectionist crap and realize that for many modes, the handwriting is on the wall for analog. The way the current rules are written in Part 97 makes most new digital modes second-class citizens on the bands. Bogus and Sad IMHO in almost-2012.

— /SOAPBOX —

New project– BATC DigiLite DVB-S Modulator

Note: a longer and more technically detailed version of this is at my other 'blog, which I've decided not to syndicate.

Why was I up to 3 AM last night, making me miss the Iowa QSO party today? I received a care package via “Royal Mail” on Friday from the British Amateur Television Club. It is something that was designed almost the same way (actually more clever in many respects) that I had been thinking of doing for close to 10 years.

The DigiLite is based on the “Poor Man’s DATV” by F4DAY. The project has been updated for modern computers by using a 2 channel FTDI USB serial port chip (which is the “why didn’t I think of it?” part of the design) and a closed-source (unfortunately) DSPic33 and Windows PC software to capture data from a “e-bay special” several year old Hauppage PVR-150, 250, 350 (and probably PVR-USB2) analog capture card from e-bay. (What is special about them for this project is an Conexant MPEG-2 encoder hardware chip and they are cheap!)

BATC Digilite card 3/4 way assembled at W0FMS -- topside

BATC DigiLite card 3/4 assembled at W0FMS -- bottom

The BATC’s solution of using an inexpensive PIC and the FTDI serial interface is a maybe slightly kludgy but awfully clever solution of inexpensively and simply pumping data to the QPSK modulator chip. Although there are some disadvantages to this simple interface, it is an awesome start!

The modulation used is DVB-S, which is the older digital standard used by most of the world for satellite transmissions.

I’ve been playing with LEGAL Free-To-Air satellite for many years. The majority of what is left unencrypted on C-band and Ku-band FSS satellite is receivable on an inexpensive set type box and/or PC receiver card. These receivers take in 950-2150 MHz signals as an IF (with a converter and/or a LNA in front of the IF) in Amateur use.

The main disadvantage to DVB-S for ham radio is that the modulation is pretty weak when it comes to handling multipath. Existing Yagi beams other directional antennas will mitigate this greatly in Amateur Use. See the other ‘blog for details.

THE great advantage to DVB-S for ham use– in my opinion– is that the bandwidth and data rates, even the video and audio coding the the MPEG-2 Transport streams are pretty much completely up to the link user. DVB-T in Europe and ATSC in the US is only setup for 6/8 MHz channels and IMHO there is no reason for hams to use this much bandwidth in 2011 for ATV. Neither are a good choice for low bandwidths as we NEED to have in amateur television.

Experiments by the BATC and others show that the digital signal is much more usable and stable than equivalent bandwidth analog ATV and it just gets better with reduced bit rates.

Ho, Hum? ATV? who cares? Well.. see.. it’s not really just that, is it? Data such as DVB-IP can be used for data instead. There are $20 e-bay DVB-S cards capable of receiving data as a native computer network interface via this protocol. Maybe we can restart a packet radio network up again?

So this is the start of an interesting project for me that I’ve wanted to do forever. Hopefully it will turn out well and can be revolutionary.

ARRL Midwest Division Convention

Sorry about the infrequency of posts this summer from me. Summers are a bad time for the amateur radio hobby for me every year and this one is particularly bad.

It’s been complicated by a storm that came through 5:15 AM CDT July 11th, with 70-90+ MPH sustained winds (for, I’m not kidding, 15 minutes) and took down *ALL* of my wire antennas. (Trees fell through their paths, so my designs were still mechanically solid, right?) So I’ve been very QRT and have spent the last several weekends cleaning up the lot and fixing storm damage to my house. At least the tower and aluminum antennas seemed to have survived the ordeal.

Because of all of this the amount of time I’ve had to dedicate to the hobby has been minimal for the last couple of months. I’ll get back to it when I can. I had a bunch of antenna work planned before winter anyway.. now I have twice as much! :O(

However, I am involved in a minor way on the committee that is handing the ARRL Midwest Division Convention and I am specifically handling Kit Building at the event.

Also I’m sort of the publicity guy too.. but I’m getting plenty of help for others for that role!

But, nonetheless.. I should still publicize… So here is a shameless plug for the event.

http://convention2011.cvarc.rf.org/

I’d like to personally invite all of my ‘blog readers to attend our convention in Cedar Rapids. If you are within a 250 mile one way drive.. it will be a no-brainer for a really fun and interesting weekend devoted to ham radio.

The convention will be held at:

Clarion Hotel and Convention Center – Cedar Rapids, Iowa
525 33rd Avenue S.W.
Cedar Rapids, Iowa 52404

Mention the “ARRL Midwest Convention” when booking
Reservations: 877-949-2992 Fax: 319-362-1420

If there are issues at the Clarion, since it’s getting close to the event, don’t worry..the area is “hotel row” and there are plenty of options.

On Friday August 5th, we have an educational, hands-on tutorial on getting stated with the TI OMAP processor based BeagleBoard (Rev C) and BeagleBoard XM for Amateur Radio uses. It’s the intent of a group of mostly Collins ARC guys to eventually evolve this board into a SDR but many other projects (such as D-RATS/APRS gateways, portable HF digital mode units, etc.) have also been contemplated and input on this project will be welcome. The fee is $10 for this if you are registered for the convention also, $20 if not.

On August 6th we have a plethora of interesting speakers in an “operating” and “technical” track. There is also a Youth forum (12 and under is free for the convention). In addition, Ed Hare W1RFI and Kay Craigie N3KN ARRL President will be attending. Kay will be the banquet speaker. Since this is an ARRL convention an official “Wouff Hong” ceremony will also take place. This is a grand opportunity to become a part of this “official” fraternity! The list of speakers is on the schedule page, http://convention2011.cvarc.rf.org/schedule.html

I will also personally be the master of the kit building session that includes a cute little PIC based keyer that would work wonderfully in a Rover (AA0ZZ design) and a 40m NM0S (locally designed) HamCan two transistor regenerative 1/2 to 1 W PEP output transceiver.

WA0ITP of 4SQRP fame and K0NEB the “kit building” columnist for CW magazine are scheduled to attend and have stated their intention on assisting me if needed. The kits are suitable for beginners and I will NOT let you fail building one.

Then if you are smart enough to stay the night at the Clarion, you can attend one of the region’s best hamfests on Sunday August 7th (which is an annual event even on non-convention years)… Cedar Valley ARC “Summerfest” near the hotel at:

Teamster’s Hall
5000 J Street SW
Cedar Rapids, IA 52404

Which is about 1 mile from the convention.

Hopefully I will see some of the regular viewers of the ‘blog at the event.

The day of the event is getting close. If you want to come it would be highly appreciated if you mail your registration (from the website .PDF) as soon as possible.

Just when you convinced your wife that your friends were normal…

Just when you convinced your wife that your friends were normal…

You take your wife to Dayton! 🙂 (Ok it’s been about 15 years since I did that and I can’t get my wife to come back even still!)

    Dayton 2011: Saturday– the BIG day!

Except for the toilets (sewer line) exploding in the afternoon in the flea market… it was a picture perfect Hamvention. Nothing like it ever before for me.

But it looks like driving back it will be “tornado alley”.. I’ll keep my fingers crossed…No Hail… No Hail…

Here’s the day in pictures:











Who is that crazy looking dude with the Astronaut?!?

Well.. it was all fun and games this year.. it’s a wrap for me and the Eastern Iowa DX Association.. I’m praying that the weather isn’t as severe on the way back as predicted.

It was a blast meeting everyone I met at Dayton this year.. I had great fun.. the City of Dayton looks a lot better than it did in 2004, and the weather was beautiful. I had some of the best eyeball QSOs that I’ve had anywhere.

Hopefully it won’t be 7 years before I make the pilgrimage again… catch you all on the bands, eh?

Dayton 2011 – Friday

Well.. you knew this was coming.

Here is the detail.. the smells were not all that bad this year, I ignored the so-called food, the crowd was thinner than I remember — there were less outdoor vendors than I remember — but more indoor ones. Chinese HT’s were dirt cheap, and I did have a lot of fun. I was sad that Max-Gain doesn’t come with fiberglass anymore.

The weather was as beautiful as possible, Yaesu seriously cheaped out on hats… And except for one old bag who ran over me, from behind where I couldn’t have possible seen her or heard her, with her “hover round” right when I got into the inside exhibits and then yelled at me for stopping to take a picture..(don’t worry.. I responded even more rudely) everyone.. well seemed nicer than in previous years. (Maybe losing 160 lbs helped with that?!?)

But what can I say. Except for a SERIOUS lust for a Kenwood TS-590 and an impulse buy of a Peet Bros weather station (which I’ve been considering doing for years).. I didn’t do that much or buy that much. Probably the neatest thing is the Argent USB Data APRS Tracker and the cable for my TYT .. I’ll be geeking on the way back.. track me on:

aprs.fi…

My 1st gen TYT is now going for $89+tax now instead of the $99+tax I paid for it at Des Moines.. thanks Radio City.. no.. I still love you guys but you owe me a small deal in the future! Wouxuns dual banders from wouxun.us were selling for $90 with tax…. If I didn’t live in Cedar Rapids with only one 222 MHz repeater I would have bought the 144/220 version just to have 220.. (I almost did anyway) but it’s pointless at my QTH…

But here it is.. commentary aside:

Beautiful day for a Hamvention...Yup that

What an eclectic bunch of stuff.. Yaesu=Cheap no hats-- Kenwood much better freebies!!

Obligitory Mendelsohn's shot.. also DEMI and other goodies

ARRL and international radio societies inside

AMSAT, WB4APR's "Mean Green Machine" and other oddities...

More Fun and probably lame coverage tomorrow night.. same Bat Channel


Subscribe FREE to AmateurRadio.com's
Amateur Radio Newsletter

 
We never share your e-mail address.

Please support our generous sponsors who make AmateurRadio.com possible:

KB3IFH QSL Cards

Hip Ham Shirts

Georgia Copper

Ham-Cram
Expert Linears

morseDX

Ni4L Antennas

N3ZN Keys

West Mountain
R&L Electronics


Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on AmateurRadio.com!

Have a ham radio product or service?
Consider advertising on our site.

Are you a reporter covering ham radio?
Find ham radio experts for your story.

How to Set Up a Ham Radio Blog
Get started in less than 15 minutes!


  • Matt W1MST, Managing Editor