I’m now up to Experiment #16 in Make: Electronics; about half way through. I’ve learned a good bit, even though the book is definitely aimed at newbies. I have skipped a couple of experiments that didn’t seem like they offered enough new experience for the amount of effort they would require.

I would recommend the book to anyone with one disclaimer: be prepared to spend a lot on tools and supplies. I’m also not terribly fond of the author’s recurring intruder alarm example. I feel like he could have come up with a better project. On the other hand, I don’t know of a better hands-on, beginner’s guide to electronics.

For now, I’m suspending my efforts on the book to finish up my DDS-60 card. More on that soon.

PanaVise Junior in action

PanaVise makes a whole series of vise bases and heads, and I’ll probably end up with several of their products, but Junior model is absolutely perfect for working on small circuit boards.

A similar product is the ubiquitous “third hand,” as seen here. I have one of those too, but I don’t use it nearly as often as the PanaVise Junior. Some people actually use them to hold to hold small circuit boards while working on them, but either their third hands are much sturdier than mine or they’re crazy. It’s nice for attaching connectors to wires and that sort of thing, but I wouldn’t say it’s essential. I got mine for $4-5 from an electronics supplier. For that price, it’s not a bad deal for occasional use.

Along the same lines, I have a pair of medical hemostats that I use for holding things. For instance, a lot of projects will require you to solder headers onto a circuit board. It’s virtually impossible to get the headers to stay where you want them. I use the hemostats to hold the headers while I solder one pin. Remove them, check for alignment, reclamp, and solder the far pin, then remove and solder all the other pins. It makes dealing with headers much easier. It got mine from SparkFun for a few dollars.

I got a Circuit Specialists Soldering Station for $45. It’s a 40 watt temperature-controlled station. I have the one with the digital temperature display, but they have an analog version for $5 less. The analog one is more than accurate enough, but I like the digital look. It comes recommended by others, and I have no complaints. The grip on the iron gets a little hot, but not to the point of being uncomfortable. I’ll probably upgrade eventually, but I expect it’ll be several years. You could probably get by with a non-temperature-controlled iron, but I think this one is definitely the best bang for buck.

For through hole work I use a 1.2mm chisel tip. Most people would probably use the next size up, but I enjoy the extra control the smaller tip gives you. For surface mount work I use a 0.8mm conical tip.

I decided on 63/37 Kester 285 solder, in 0.031″ diameter for through hole and 0.015″ diameter for surface mount. The 63/37 refers to the percentages of tin and lead in the solder. The 285 refers to the type of flux. Flux helps the solder stick to the objects you’re trying to solder. While solder sticks to metals like copper very well, it doesn’t stick to oxides very well. Unfortunately, the high temperatures involved in soldering cause accelerated oxidation. Flux helps prevent oxidation and also serves as a wetting agent, causing the solder to flow. Some fluxes must be cleaned off the board after soldering. I don’t have time for that, so I settled on Kester’s 285, the most active flux I feel comfortable leaving on a board. There are also “no clean” fluxes, but they tend to not perform as well. Especially while you’re learning to solder, stick with something like Kester 285. You can also get lead-free solder, but it’s not beginner friendly either.

I bought my solder from Digikey in 1lb. spools. It runs $20-30 per spool.  It’s hard to find good solder in small amounts. Radio Shack has small quantities of solder, but I have no idea if it’s any good. If you’re just getting started in this hobby I’d be glad to give you some solder. There’s no way I can use it all before it goes bad. (This type of solder has a shelf life of three years or so.)

I also have a flux pen, but I’ve only used it a couple of times when hand soldering surface mount ICs.

You need a way to clean your soldering iron’s tip. Most irons come with a cheap sponge that you wet. I use a Hakko 599B tip cleaner. It looks like a pot scrubber, but it has flux on it that cleans your tip. It also doesn’t drop the temperature of your tip like a wet sponge.

Sometimes you need to remove solder. There are two basic ways to do this: a desoldering pump or desoldering wick. The pump seems to be the old standby, but I’ve had way more luck with wick. I never use the pump these days. I use TechSpray wick and it does a good job. I use size #3 for through hole components and size #2 for surface mount.

I use Xcelite 378M pliers and 170M shear cutters. Amazon has them for $14 as a pair. You can make do with a small pair of regular pliers, but cutters like this are virtually essential. Home Depot carries an identical set under the Cresent brand.

Good lighting is essential for this sort of thing. While not ideal, I use a Petzl headlamp when soldering. Magnification is also important. I have a 10x jeweler’s loupe that I use for checking joints after the fact. I’d love to have a lamp/magnifier combo that clamps to my desk, but they’re expensive, and I’m sure my kids would find a way to break it. One of those magnifier visors would be nice too.

So, yes, getting setup to solder is a little on the expensive side, but it’s not bad compared to a lot of hobbies, you don’t have to buy it all at once, and it’s a good skill to acquire. Let me know if you have any questions.

Dummy load in vise, on desktop.

So, what the heck is a dummy load? When you’re testing a transmitter, you can’t just transmit without anything connected to the output. You could fry your final amplifier. So you need a dummy load that presents the correct impedance, 50 ohms in most cases. As it just so happens, I’m getting ready to build a transceiver, and will need a dummy load for testing. Also, this particular dummy load involves several surface mount (SMT) parts, and I wanted a little practice with those before beginning my next project, the Softrock Lite II 30m software-defined receiver.

This kit was designed and sold by NorCal QRP, a low-power (QRP) ham radio club based in Northern California. They have put together several kits over the years. They actually retired this kit a couple of years ago, but I inquired on the qrp-l list and someone had one they weren’t planning on building.

Some hams are intimidated by surface mount (SMT) components, and rightly so; they’re pretty small. Have a look below. The small black thing to the right of the penny is a 2.2 kOhm SMT resistor. SMT components come in different sizes. This size is referred to as 1206, which means it’s 0.126″ × 0.063″. It’s one of the larger sizes of SMT components.

As it turns out, soldering SMT components isn’t too bad. I used a small tip on my soldering iron and small solder (0.015″ diameter) and had no problems. There were no SMT integrated circuits on this project, but there would be on my next project.

Tonight I started on another SMT project, but using solder paste, a griddle, and an embossing gun instead of solder and a soldering iron. More on that later.

After checking out the reviews on Amazon I settled on Getting Started in Electronics by Forrest Mims. It has glowing reviews, many reviewers crediting Mims for jumpstarting their career in electronics. It’s also very short, at 128 pages.

I’ll be honest, I was disappointed. I’m probably a little more experienced than the target audience for this book, but not by much. While I did learn a few things, I found it to be way too high-level and not at all hands-on.

My next attempt at gaining an intuitive understanding of some electronic concepts will be via Make: Electronics. It’s a relatively new book by the guys at Make Magazine, of which I’m a subscriber. I read an interview with the author and editor a few days ago, and they actually mentioned that their intent was for it to be a modern day replacement for Getting Started in Electronics. (GSiE was originally published in 1983.) From reading about the book, it is decidedly more hands-on. While I’m sure some of it will be repetitive for me, I expect to learn quite a bit as well.

While I’m waiting on that to arrive, I’m going to read a couple of Sherlock Holmes short stories. I hope to see the new movie in the not too distant future, and I don’t want my image of Holmes’ world to be tainted by Hollywood.

While I’m very excited about the ATS-3B, I’m going to force myself to leave it alone until I finish my Softrock Lite II 30m software defined receiver and my Small Wonder Labs SW-40+ 40m CW transceiver.

I’m not sure I’ve even mentioned my Softrock Lite II on the blog before. I’ll have to do a proper post on it soon. I have mentioned it over on Twitter. It is done, as in all the parts are installed. However, I’m not able to receive any signals. The helpful guys on the mailing list tell me it needs a proper 50-ohm antenna. I was trying to use a small piece of wire as an antenna for testing purposes.

I have ordered and received everything I need to build a 30m dipole antenna that will be installed in my attic, at least for now. I’ve even cut the wire to length. I just need to solder everything and put it in the attic. I’ll probably borrow an SWR meter from one of the local hams to ensure it’s resonant on the 30m band. Hopefully the Softrock Lite will just work once it has a proper antenna. If not, I’m confident I can troubleshoot it with the help of the guys on the mailing list.

The SW-40+ is mostly done. All the components are installed on the board. However, I still need to align it, integrate the K12 keyer, and put it in the enclosure. I’ll also need to learn Morse Code before I can get much use out of it. I’ve been practicing occasionally, but I’ll have to put a lot more time into learning it before I’m good enough to try an on-air contact.

I’ve also been tinkering with AVR microcontrollers, but that’s a long-term project, so I’m content to let that sit while I build the ATS-3B.

I hope to get up a post about the backpacking trip soon. Two things are holding it up. Mostly, I’ve been insanely busy since I got back. Secondly, the memory card that has the pictures from the trip on it seems to be corrupted. I’ve ordered a card reader so I can attempt to recover them.

Last month NIST updated WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers (PDF), its guide to making and using WWVB-controlled clocks. WWVB operates at 60kHz, way down in the low frequency band. A half-wavelength antenna for WWVB would be a little over a mile and a half long. NIST also operates WWV, which broadcasts at 2.5, 5, 10, 20, and 25MHz.

Building a WWVB-controlled clock is on my list of electronics projects, but it’s not one I intend to get to anytime real soon.

The ATS-3B was designed by Steve to be the ideal radio for backpacking. He lives in New Hampshire and backpacks the Appalachian Trail often.  (ATS stands for Appalachian Trail Sprint.) I haven’t done much backpacking lately, but I’m looking to get back into it soon.

Most ham kits use through hole parts, which are easier for some people to handle. The ATS-3B uses lots of surface mount parts, allowing it to be very small. I’ve used surface mount parts on a couple of projects and actually prefer them. I’ve always soldered them by hand. Steve seems to prefer the solder paste/warming plate/embossing gun method. I’m not sure if I’d give that a try or stick with soldering by hand. Here’s a YouTube video of Steve doing it both ways.

Steve only offers ATS-3B kits periodically. I believe he’s offered them about three different times now. He’ll be offering them again sometime in late fall, and I’ll be ready. This will also be the last time Steve will offer this kit, as some of the parts he uses are being phased out. He’s already working on the ATS-4, which looks to be a very nice (though somewhat larger) radio.

The 40m ham band is a good all-purpose band. It’s open to somewhere pretty much any time, day or night, even at this point in the solar cycle. QRP means it’s low-power. In this case, around 2.5 watts. Most commerical radios put out around 100W. CW means it only does Morse code, no voice, which means I’ll finally have to learn Morse code.

The SW+ series is well-regarded in the QRP community. There are models available for the 20m, 30m, 40m, and 80m bands. The kits are put together by a guy in New Hampshire. There’s a waiting list of around two months to get a SW+ kit.

The SW-40+ board with 8 of the 16 sections installed. I've added a couple of sections since this photo was taken.

A few weeks ago I finally got a chance to start putting mine together. The instructions that come with it basically say to build the whole thing, then test it. I’ve built some smaller kits before, but this is definitely my largest undertaking thus far, so I wanted some assurance things were going right as I built it. So, I’ve been using Chuck Adams’s, K7QO, guide to building the SW-40+. By following his guide, you build a section, then test it. He has it broken down into 16 sections, more or less. Some of the previous kits that I’ve built are used for testing.

You can see all the pictures from the construction process here. I’ll continue to add photos as I go along. I’ll post an update here occasionally too. So far I’ve installed the power supply, audio amplifier, keying, muting, audio preamplifier, receiver mixer/detector, IF crystal filter, receiver mixer, VFO, and transmitter mixer sections. That’s 10 of the 16 sections.

Testing the transmitter mixer section by feeding the output of the transmitter mixer into the receiver.

A few months ago I bought a VE3DNL Marker Generator kit, but had never put it together. Chuck suggested using it to test the receiver mixer/detector section. It was a quick build, and the receiver mixer/detector section passed the test.

VE3DNL Marker Generator board is on left of SW-40+ board. The VE3DNL transmits tones every 5kHz that can be picked up in the SW-40+ receiver.

After building the VFO section I wanted to have a look at the waveform. Chuck’s guide shows a nice sine wave. A friend had loaned me an oscilloscope for another project a few months ago, so I drug it out and set it up. To make a long story short, I was never able to view the VFO’s waveform on the oscilloscope. Something is wrong with either the probe or the oscilloscope itself. However, I was able to confirm that the VFO is running at around the correct frequency with the FCC-1 frequency counter I built a while back.

I have also built a K1EL K12 keyer to put in the SW-40+. As designed, the SW-40+ can only use a straight key. I wanted to be able to use iambic paddles, so I found the K12 keyer. It handles the input from the key and outputs perfectly spaced Morse Code. It sounds beautiful. It’s a pretty cool little device in its own right. I may do a post on it at some point.

The K1EL K12 keyer assembled.

More on the SW-40+ when I get a chance to work on it.

The MintyBoost allows you to charge most USB-powered devices from two AA batteries. Actually, if you want to get creative you can connect anything that provides between two and five volts of DC. This guy uses two D batteries.

The top of the MintyBoost circuit board with all components installed. To give you some idea of the sizes involved here, the PCB, from top to bottom, is about the size of a penny. Click on the image to go to its Flickr page. The Flickr image has notes describing the components and their purpose.

The primary purpose of this kit was for me to get some experience soldering. I’ve done a little soldering before, but very little, and never on a printed circuit board.

The heart of the MintyBoost is the LT1302 integrated circuit. There are a few capacitors to smooth out the input and output, a diode for reverse current protection, an inductor for the LT1302 to store energy to be converted, and some pull-up resistors to convince the USB device to charge. You can see the step-by-step building process here.

Apparently there’s no agreed upon standard for USB chargers. Most Apple products will charge if their two USB data lines are pulled high. The MintyBoost uses two 100k resistors for this. Other devices require other values of pull-up resistors or even pull-down resistors.

The bottom of the MintyBoost circuit board after soldering.

The actual performance of the MintyBoost for charging my iPhone is a little disappointing. I get a little better than half a charge when using freshly charged Sanyo Eneloop AA batteries. At first I thought that the circuit could be improved by limiting the current through the MintyBoost with a single resistor. However, after I did the math correctly, that turned out to not be the case.

As it turns out, the iPhone just doesn’t charge very efficiently. USB (and thus the MintyBoost) provides 5V DC, but the iPhone battery is 3.3V. The iPhone undoubtedly uses a linear regulator in its charging circuit, which means it effectively turns into a heater when being charged. The extra voltage is just released as heat. Switching regulators are more efficient, but more complicated and expensive. Plus, when you’re charging from your computer or an outlet, it really doesn’t matter.

When I first saw the MintyBoost printed circuit board I thought both it and the pads on it were very small. Once I got started it was no problem though. It is easily doable as a first project.

I’ve got an Altoids gum tin ready for it to go in, but I need some more double-sided tape. I’ll post some more pictures once I get it in the tin.

Most of my “interesting stuff” is ham and/or electronics related. I got a soldering iron for Christmas, and I’ve put together a few kits and I’m in the process of putting together a few more, including an SDR receiver and a Morse code transceiver. I’ve also started tinkering with AVR microcontrollers.

During the holidays Luke got in the habit of going to sleep really late. After the holidays, he kept it up. I’d guess than during January, his average bedtime was 10:30pm. That doesn’t leave much time for dad to play with his toys. Luckily, he’s been going to sleep around 9pm the last week or so. He slipped a little tonight, but I’m not too worried about him regressing.

In other sleep-related news, we had been letting Liam sleep in his swing for the past few months. We knew it was a bad habit to form, but he slept so well in it. He went from getting up 2-3 times a night to 0-1 times a night. This week we finally decided it was time to break the habit. The first few nights were rough, but last night he only got up once. Luke got up once until he was about 15 months old (Liam is only 6 months old), so I don’t guess we can ask for much more.

So, if the boys keep up their good sleeping routines, you should be seeing a lot more posted here.