Electrically powered soldering iron is composed of a heated metal tip and an insulated handle. Heating is achieved electrically, by passing an electric current through the resistive material of a heating element.For electrical and electronics work, a low-power electrically heated soldering iron, a power rating between 15 and 35 watts, is typically used. Professional typically use temperature controlled (thermostat) soldering irons that have somewhat higher ratings (often 40-80W).

The soldering iron temperatures used for electronics soldering are typically between 260 and 350 degrees celsius. Your iron will not melt metal if it is too cold and you will have a hard time soldering if the iron is too hot. If you use too hot iron, you risk damaging the circuit board and electroncs components. For electronics work a temprature controlled soldering station is preferred. There are variety of means are used to control temperature. The simplest of these is a variable power control, much like a light dimmer. Better soldering irons use thermostat control.

Here is thermostat controlled Velleman soldering station I use:

Soldering irons are easy to use but you will need a little bit of practice before you can do some precision work. For tips how to work with soldering irons, watch this Soldering basics and choosing a cheap soldering iron video.

There are some true classics in soldering iron market. There are a handful of manufacturers who make products that are legendary for lasting forever, and who still support their products made a lifetime ago. These are usually those who set the standards in their field.Weller is one of those companies. Long-Term Review: Weller Magnastat Soldering Iron article gives a review of one truly classic soldering iron model.

On the other side od the market are the very cheap soldering irons. To get idea how they are watch this Inside the cheapest soldering iron on ebay andEEVblog #596 – World’s Cheapest Soldering Station – Yihua 936 videos:

Here are some quick tips for safe soldering and desoldering when necessary:

Selecting Your Solder: For electronics works there are two main types of solder – leaded and lead free. Treaditionally soldering for electronics has been done with tin+lead solder (typically in 63/37 and 60/40 moxes). Leaded solder is easy to work with, but contains poisonous lead (make sure to wash your hands regularly to avoid absorbing it). Another option is lead-free solder. It does not contain lead, but the flux in lead-free solder is much more active than the rosin (literally pine sap) flux in leaded solder (typically much more irritating to your eyes and respiratory tract). To solder with lead free solder, you typically need to use higher temperature and soldering iron with better temperature control. A “good” lead-free solder joint is grainy and rough. If you do repair work, use the same solder type (leaded or lead free) that was originally used, because mixing leaded and lead-free solder can lead to unexpected results.

Catching Your Breath: Soldering produces fumes, and you don’t want to breathe them in. Ensure that your workspace is well ventilated (exhaust fan is a good idea).

Protecting Your Eyes: Safety goggles are an important part of any safe workspace. Spatter may be rare, but it’s always better to be safe than sorry.

Never forget that your soldering iron is hot! Make sure that you only hold it by the insulated grip, and always return it to its stand after you’ve used it.

A clean iron tip means better heat conduction. Use a damp sponge to wipe the still-hot soldering iron between uses. An alternative is to use solering iron cleaner with Brass wire sponge. How Is a Wet Sponge Used?

KiCad is an intereresting open source EDA software for Windows, OSX and Linux. Create PCB circuits for free with the most advanced features. With the schematic editor you can create your design without limit; there are no paywalls to unlock features. An official library for schematic symbols and a built-in schematic symbol editor help you get started quickly with your designs. It can make professional PCB layouts with up to 32 copper layers. KiCad also includes a 3D viewer which you can use to inspect your design in an interactive canvas. You can rotate and pan around to inspect details that are difficult to inspect on a 2D view.

EEVblog #253 – KiCAD Install & Schematic – First Impressions video is a continuous 45min screen cast of Dave installing and running KiCAD for the first time, along with his first impressions and rants about things he finds along the way, mainly with the schematic editor portion of the program. How easy and intuitive is it to use the schematic editor for the first time?

For more advanced introduction check out  KiCad video series: from concept to manufacture. It shows people how to design and build their very first PCB using this software

Here is some more information links related to KiCad:

CERN Shows Off New KiCad Module Editor CERN, the people that run a rather large particle collider, have just announced their most recent contributions to the KiCad project. This work focused on adding new features to the module editor, which is used to create footprints for parts. The update includes support for DXF files, which will make it easy to import part drawings, or use external tools for more complex designs. CERN has already implemented a new graphics engine for KiCad, and demonstrated a new push and shove routing tool. Check out the CERN KiCad Developers Team on Launchpad.

A Simple (and Dirty) Bill of Materials and Stock Management Utility introduces you to a simple bill of materials generation too “For a better BOM in Excel“, which can also do simple stock management.

If you need to export to other tools, check out KiCad Script Hack for Better Mechanical CAD Export article for ideas.

How to Buy a Multimeter covers what you need to know to select a meter for DIY electronics. It focuses on the needs for audio electronics, but it’s purposely kept general in nature.

Handheld Digital Multimeters are mainly used to measure resistance, as well as DC/AC voltage and current. Common multimeters can be divided into two types, desktop and handheld digital multimeters depending on their sizes. A handheld digital multimeter is basically composed of Analogue Front End (AFE), MCU, Human-machine interface and Power supply. The design of handheld multimeters should focus on the features of low power, high performance and compact size.

Look for these features when buying a multimeter article tells that multimeters can be handy for troubleshooting PC power problems (I would say it is a must have). But the range of features and prices can be confusing when you’re shopping for one. Before you waste time and money, find out which features are essential and which are merely nice to have.

EEVblog #75 – Digital Multimeter Buying Guide for Beginners

EEVblog #91 – $50 Multimeter Shootout – Extech EX330, Amprobe AM220, Elenco, Vichy VC99, GS Pro-50

$50 Multimeter Comparison and Teardown article tells about a very nice video series on multimeters. Here is maybe the most interesting video from it:

$50 Multimeter Shootout – Part 7 – 15 DMMs Compared! – Teardowns – #0074

There are countless cable tracers on the market, but they all operate on similiar principles. They transmit a signal on to the cable and have a receiver that detects that signal.

Method: use the tone generator and the probe to determine where a cable is going and whether or not (and where) the cable is interrupted.

The Tone Generator is a hand held, battery powered instrument designed to perform a variety of tests on unenergized telephone lines or LAN cables. Alligator clips and a standard RJ11 plug allow the tone generator to be connected to stripped wires, terminal panels, wall plates, or modular single line jacks. The Tone Generator usually generates continuous tone or warbled tone with selectable test frequencies. Frequencies are usually around 1kHz frequency.

Here is a video that shows how to use Tone and Probe Cable Tracer.

The Line Tracer is a hand held inductive tracer that will help to identify wires without piercing the insulation. It can trace Tone Generator signals through dry wall, wood and many other non metal surfaces.

The conventional use of the inductive amplifier is the location of breaks in hidden wires, even buried in concrete. The typical wire detection range in a concrete wall is 10-20 cm. One of the manufacturers of the inductive amplifier is Tempo. Inductive amplifiers can also be used to find an individual cable pair in a telephone cross connect or cable head when used in conjunction with a tone generator.

Inductive amplifier can be used to trace mains wiring inside the wall. In case the mains wiring is is or can be reliably disconnected from mains power source, it is possible to trace disconnected mains wiring like telephone wiring is traced. Make sure the power is off before connecting the tone generator. If live mains wiring needs to be tested, you need tools specific for that: Voltage detectors are helpful once you find your wires — they let you test whether the wires are live. You can also buy circuit and wire tracers made specifically for the purpose of locating electrical wiring behind walls and underground. These tools tend to be expensive, though.

Some instructional articles:

How to Use a Wire Tracer article gives you some basic instructions.

Deciphering wiring article has some tips on cable tracing and notes cases where tracers do not always work well.

How to find an open circuit or shorted wire the FAST easy way

Are you interested in circuit diagrams of cable tracers? Here are some pointers to those:

My Cable tracing inductive amplifier blog posting  has several circuit diagrams.

Fox and Hound cable tracer article has links to generator circuits.

Fox – Hound, Cable Tracers, Signal Tracers, Line Tracers – whatever you want to call them project page has circuit diagrams.

Cable wizard cable tracer manual has many circuit details in it.

It seems that RSS did not fully live up to the promise for end user perspective. It is useful technology that I use in this blog (http://www.epanorama.net/newepa/feed/). RSS feeds have been very popular, but are are somewhat fading in popularity, even to point that some articles expect death of RSS. Nowadays the trend is that people follow Twitter and Facebook instead of RSS. One of the best aspects of email subscriptions (and Twitter) is that you can actually see who’s taken interest in your work. 

Is RSS dead or not? To me, anytime someone says a tech is dead it usually means that tech is not very interesting to discuss anymore, or isn’t seeing the most innovative companies doing new things with it. Ultimately RSS will stick around as a way for content services to talk to each other (it does that well). The protocol is still very much alive, while people can get the data from other means than RSS from various services, very often RSS is the method that gets the data to the service people use. On thing to remember is to make sure that your RSS feed content is valid, I tested my feed to pass the validation service at https://validator.w3.org/feed/.

I still offer RSS feed at http://www.epanorama.net/newepa/feed/. I also post updates to Twitter and Facebook.

If you prefer to get update on material posted to this blog to clutter your email box (I post here quite often), there are many RSS to mail services.  From various alternatives I found out that Blogtrottr worked the way I liked. You can get information on new postings to your e-mail box using Blogtrottr by giving URL http://www.epanorama.net/newepa/feed/ and your e-mail address to this service, and selecting feed type (Realtime works well).

WordPress is very nice blogging platform for users, but because of many options available and huge popularity there are also security issues on the systems. Many security issues have been uncovered in the WordPress software over the years, and new ones come out every now and then.

So how to handle Wodpress security issues to keep your blog safe? Here some of my tips targeted especially for those who run WordPress software on their site (if you use WordPress hosted by for example wordpress.com issues are somewhat different):

Typical hacking and malware problems with WordPress installs, if you’d like to review your own WordPress setup, include: Poor password hygiene, including weak passwords, shared or re-used passwords, and no two-factor authentication. Poisoned third-party content such as adverts served from external servers. Use plugins only from trusted sources.

Make sure that you ahave all the security related settings in wp-config.php set in sensible way. For some tips on this check WordPress Security: Part 1 Securing wp-config.php and Conquering the wp-config.php File – 11 Good Practices.

When you access your site management at Linux shell level, use always secure communications methods. I recommend to access Linux server shell with SSH and files with SCP. It is also a good idea if you use SSH certificates for authentication istead of normal username+password. Do not use telnet or FTP because they are insecure. If possible perform your WordPress administration through web interface throug HTTPS instead of HTTP.

Make sure that you keep the WordPress up to date. You need to be prepared to update your WordPress and plugins when new security issues get published. Update quickly when serious security issues are reported. Unpatched WordPress software or plugins, leaving known security holes open for attackers. If possible, use automatic updating service.

Design a backup procdure to back up your site contents. You will need that in case somone hacks your site or there are serious problems on your hosting side. So make regular backups. Your WordPress database contains every post, every comment and every link you have on your blog. If your database gets erased or corrupted, you stand to lose everything you have written. There are many reasons why this could happen and not all are things you can control. With a proper backup of your WordPress database and files, you can quickly restore things back to normal. Site backups are essential because problems inevitably occur and you need to be in a position to take action when disaster strikes. You need backups! Spend some time to make an easy, convenient backup of your database will allow you to spend even more time being creative and productive with your website. Do not end up losing a few months of hard work due too no backups. Make sure that the backups you have made really work (that you can restore data from them in case you really need them, non-working backups are just waste of time).

There are several methods of automating the backup process available. Various plugins exist to take automatic scheduled backups of your WordPress database. I have found that Vaultpress a good WordPress automatic backup service: it supports realtime syncing of all WordPress content to the VaultPress servers for a reasonable montly fee. I use Vaultpress for real-time backup and I also make my own backup files (database dump and WordPress directory contents) to another server periodically.

When you run WordPress on your own Linux system or some shared hosting Linux server, it is very important to to set the file and directory permissions right. Generally less permissions you give, the better for security, but if you do not give enough permissions your WordPress does not work. What permission do you suggest for wp-config? article recommends for your own server: Directories 755, files 644, (sometimes, the upload directory will require an exception). Permissions any lower that still permit functionality on your particular server setup is fine (lower number is more secure). If you use shared hosting service, you should make sure that other users can’t read your sensitive files, especially wp-config.php (use 750 permissions). Overly-liberal access controls giving too much power to too many users.

Keep your wp-config-.php file secure bcause wp-config.php that contains your database password and main admin credentials. If you are in shared hosting site (or any server that has many users), the permissions of your wp-config.php should be 750 (lower): It means that no other user will be able to read your database username and password.  Changing permissions to 750 effectively removes both the “read” and the “execute” options for “others” or world. You can be even more restrictive. If the website works with wp-config.php set to 600 (most restrictive – will only work if the file is “owned” by the same Unix user that runs apache), try that. If not, set it to 640 (still fairly restrictive; only the owner is allowed to modify the file, but any users – specifically the apache user – that might be in the group that owns the file can still read it).

Make also sure that web users can’t get the contents of that file accidentally. In normal use if somebody tries to read that from wordpress directory with web browser, the data in goes through PHP system and the user can’t see the source code that has the details in it. But if you accidentally give users possibility to read that file in raw form without going through PHP interpreter, your secrets leak out. This can happen if you accindetally in a way or another disable PHP interpreted on your directory (some configuration error). Other common way to leak wp-config.php contents is that have some backup of your wp-config-php with some other name on web readable directory, common mistakes here are to leave copy of old version or backup with name wp-config.bak or using editor that leves temperary copy after editing like wp-config.php~ If you plan publish your site contents on some open source repositorio (like github), you need to be careful that you don’t publish your wp-config.php contents to the world, because that would allow someone else to hack to your site and even cost you a lot in hosting bill. You can also consider if moving wp-config outside the web root really beneficial.

Consider using some firewall system between your WordPress server and world. There are several options here. One option is to have a separate firewall device or server webween your WordPress server and Internet. It is a good idea to block everyhting you don’t need to access, and maybe route the web traffic thoiugh some proxy server that can filter out dangerous requests. Cloudflare is one well known company that sells cloud service for this (you route your web traffic through their service). If you want to run some protection software on your own server, check out ModSecurity open source application firewall. It has worked for me well (protects agants many nasty stuff), but can have some downsides (for example sometimes causes unexpected Internal Server Error problems when using management interface and the moderated comments contain certain keywords in them).

If your blog is very important to be always on-line (generated lots of money or donwtime causes lots of negative PR) and/or your blog talks on sensitive topics that someone might want to silence, be prepared to plan against DDoS (Distributed Denial of Service) attacks. It is hard to protect agains DDoS (lots of work for good protection), so you first need to think what level of protection you could need. How To Protect Your WordPress Website Against DDoS Attacks article gives some ideas on how to plan DDoS protection. Cloudflare is one well known company that sells cloud service for DDoS protection.

19 Awesome Product Improvements – At First, I Thought This Was Ridiculous. Then I realized some of them were Pure Genius.

What’s something that you never notice may be wrong (or can be changed) until you see it done in a different way? – but is the new way really better than the old one?

End of an Era: The Golden Age of Tech Blogging is Over article tells that like the film industry, the Golden Era is the emergence period, when fresh innovation in a new medium is born. New techniques, revolutionary content, and different business models emerge as innovators pioneer a new medium.

Trend 1: Corporate acquisitions stymie innovation
Trend 2: Tech blogs are experiencing major talent turnover
Trend 3: The audience needs have changed, they want: faster, smaller, and social
Trend 4: As space matures, business models solidify –giving room for new disruptors

The Future: A New Era is set to Emerge – Tech blogging isn’t dying, it’s evolving.

This is a normal part of any industry.

Golden Age of Tech Blogging Done? I Couldn’t Disagree More article put out a view: No way. Unless of course, he means we’re about to enter the platinum age. Because things are far from dead in tech blogging– and blogging in general. In fact, I think we’re poised to enter one of the most exciting periods yet. I’m a big believer that tech trends tend to over-promise in the short term but under-promise in the longterm. Last few years demonstrated some of the limitations of blogging– ie, we can’t all make businesses and build big audiences, it won’t replace all older forms of media. In a lot of ways sites like Facebook, Yelp and Twitter have scratched that itch for self-expression by giving the masses an easier and more painless way to get the endorphin rush that blogging gave in the early day. But there are still plenty of people who love to write– not just share, Tweet and comment– for a living, and blogs are still the best platform for that. In many cases, blogs haven’t yet figured out a way to monetize their influence. Start out with a mindset not to sell.

The trend toward increased complexity in software shows no sign of abating, and modern hardware creates new challenges. Programmers in the late 1990s had to target PCs at the low end that had an abstract model a lot like a fast PDP-11.  Now, mobile phones are starting to appear with eight cores with the same ISA (instruction set architecture) but different speeds, some other streaming processors optimized for different workloads (DSPs, GPUs), and other specialized cores.The Challenge of Cross-Language Interoperability article tells that interfacing between languages is increasingly important.

Analog circuit design kit jointly by ADI and Digilent article tells that Analog Devices, Inc. (ADI) and the leading design tool/board vendor Digilent have unveiled two all-in-one analog design kits for electronics engineering students to practice and learn analog circuit design. This low-cost analog hardware development platform and components is offered at price range of a typical student textbook ($99/$199/$279 USD). It comes with downloadable teaching materials, online course material, online support, textbook, reference designs (circuit diagrams) and lab projects.

I can agree with the claim that active learning – learning by doing – helps engineering students understand the process of breaking down larger problems into smaller, more easily solved parts without losing the overall understanding of the complete system. The old teaching system is expensive: A lab bench costs $5,000-$10,000 to replace; to establish a classroom is at least $100,000 and another $100,000 to man the labs.  Doing experiments outside the classroom is a way to get people engaged in the process earlier. This is great step beyond experimenting with sound card oscilloscope, smartphone signal analyzer and tablet signal generator. This is market where there are also several other products (for example PCSGU250 Velleman USB-PC Scope + Generator). Here is Analog Discovery Introduction video:

Analog Discovery 2 channel scope, waveform generator, logic analyzer article tells that Digilent’s Analog design kit is a 100 MSPS 2 channel scope, a 2 channel 100MSPS waveform generator, and a 16 channel logic analyzer built into one. The design kit is built using analog semiconductor chips from ADI including: Two 50 MSPS / 5 MHz 14 bit differential oscilloscopes (1 MΩ, 24 pF) ±25V max, Two 50 MSPS / 5 MHz 14 bit waveform generators (single-ended, arbitrary waves up to +-5V at 22 ohm impedance), Two fixed power supplies (+5V 50mA, -5V 50mA), 16-channel logic analyzer/pattern generator (3.3V CMOS 100Ms/s). The device is USB powered and portable sized. The provided controlling software is available for Windows (XP and newer) that can do in addition to basic oscilloscope and signal generation also Network analyzer (Bode, Nyquist, Nichols transfer diagrams of a circuit 1Hz to 10MHz),  Spectrum Analyzer (power spectrum, spectral measurements, noise floor, SFDR, SNR, THD, etc.) and Digital Bus Analyzers (SPI, I2C, UART, Parallel). It should also be supported by MATLAB / MATLAB student edition. There also SDK available for Linux (Debian). If you are interested, Analog Discovery Kit is available from Farnell and some other suitable sources.

Another interesting somewhat similar device is Red Pitaya. Red Pitaya is designed to Red Pitaya turns your smartphone, tablet or PC into many instruments like Generator, Spectrum analyzer, PID controller, Oscilloscope, Frequency response monitor etc. This looks like another student’s dream. It is more expensive ($470) but has also somewhat better specifications to compensate the price. This open-source device was funded through Kickstarter.

For a quick overview of the board, users will find two analog inputs and two analog output (125 megasamples per second with a 14-bit resolution). In addition, the board is coming equipped with a dual core ARM Cortex processor plus a Xilinx Zynq FPGA. As a result, 16 GPIO pins can be used with the FPGA and four pairs of differential pins for serial data transfer and synchronization. It includes Ethernet, USB, SATA, and JTAG connections. There is open-source repository where code and tools can easily be accessed for further development or use. Programmers can develop code in HDL, C/C++, scripting languages such as Perl or Python, MATLAB, or HTML Web applications. If you want to get the device you need to go to RS Components Ltd.