Blue is Terrible

This is a quick follow up to my post a few months ago about Sharpie Gel Highlighters.

At the time I wrote the post, I was still ecstatic over the discovery of this wondrous innovation. Now, after I have had a chance to use more than just the yellow one, I'm going to reply with the sage advice won from experience.

These are the best highlighters I have ever used, with one small exception.

The blue one is awful. After I took the following picture, I threw the blue one away.

The purpose of a highlighter is to draw attention to things. The four other colors are brilliant and obvious.The blue one can barely be seen on paper.

If anything, the blue shows up better in the above picture than it does in person.

I now understand why I couldn't find the five color set in stores. If you are going to buy them, go with the four pack. It has yellow, orange, green, and pink. All four of these colors are vibrant and easy to see. Don't spend the extra money to get the blue one. It is not worth it.

Soldering Irons

One of my readers asked the question recently:

What do you use for soldering?

That was a topic that I hadn't thought of writing about. Today, I fix that.

Soldering is a vital skill for playing with electronics. Breadboards and twisting wires together are useful for prototyping, but they will only get you so far. They leave much to be desired when you want something reliable and durable.

Soldering is one of the best ways to make electrical connections. It is easy to learn, and all it takes is a good bit of practice to become proficient.

But, I have to admit that decent tools make it much, much easier to learn.

Like many, I started off soldering with a very cheap soldering iron. It was old, underpowered, and not temperature-controlled. But, it was free.

There are several problems with cheap soldering irons. If it is a low-wattage model, it will take a while to get up to temperature. Trying to solder with an iron that is too cool can actually increase the likelihood of damaging some of the more delicate and temperature sensitive electronic components. The iron is too cool to melt the solder effectively, but it is hot enough to cause harm. This is usually made worse since you will be holding it against the part you are trying (and failing) to solder for a much longer time than usual.

If it is overpowered, or if even a lower-wattage one is left on for too long without using it, it will get too hot. This will make it more likely to damage things as well. Using an iron that is too hot has caused me to lift the traces off of a circuit board more times than I would like to admit.


That is what I started with. I currently own three different soldering irons:

My workhorse is a Weller W60P purchased from Altex for about $70. (As a side note, Altex is one of my favorite stores. It is one of the few remaining electronics stores that still sells soldering tools and equipment. However, they no longer carry this model.)

The W60P is 60 watts, so it has plenty of power and heats up in about a minute. It has a temperature-controlled tip, so it never gets too hot. I have never damaged a circuit board using this iron. It is a joy to use.

The only problem with the W60P is that the temperature-controlled tip doesn't get hot enough for some of the higher temperature solders used in some electronics. It is not adjustable without replacing the tip. This is why I have a cheap backup for when I need something hotter.

My high-temperature backup is a Craftsman model 113.540420. This cost about $12. It is 45 watts and without temperature control. It gets more than hot enough to work with high temperature solders.

I have the third soldering iron for portability. Sometimes it is terribly inconvenient to be tied to an electrical outlet. For those situations I have a butane-powered BernzOmatic Soldering Torch purchased from Lowes. It cost about $20. It can get very, very hot. It is suited more for soldering wires than for delicate work. It is incredibly convenient to have around. I use it mostly for working on my car, since I don't have the luxury of a garage or outdoor outlets at my apartment. The hot knife tip is also useful for cutting nylon rope.

Since it doesn't have a built in igniter, I keep a butane lighter stored with it.

That is my fleet of soldering irons. Note that the cord to the W60P is not in the best shape. It turns out that using something that gets over 700F near a cord that melts around 320F can be problematic at times.

This is why it is important to have a proper stand. In addition to avoiding melted cords, the stand also prevents the soldering iron from rolling off the table. Since things like laps, legs, and feet are typically below the edge of a table, and soldiering irons are incredibly hot, the importance of a stand cannot be overstated.

Don't forget to dampen the sponge for periodically cleaning the oxidized solder from the tip of the hot iron.

This is another useful and inexpensive tool to have around. Everyone needs a helping hand every once in a while. It takes one hand to hold the soldering iron and a second to hold and apply the solder. That doesn't leave many hands to hold the work. Most of the time it is ok setting the work on a table. However, sometimes things need to be positioned or held more precisely.

There is one other thing that is required for making a good solder joint:  good solder. I prefer small diameter solder 0.025" or so. It should be rosin core for electrical work. Never use acid core solder. Acid core solder is only for plumbing or structural applications.

60/40 lead/tin solder is good. 63/37 lead/tin solder is better. The 63% lead and 37% tin alloy is the eutectic mixture of these metals. This means that there is a single melting point instead of a melting point range. For any other proportion of lead and tin, one of the two metals starts solidifying first and then the other. If the work is disturbed while the solder is partially solidified, you get a poor connection. Using the eutectic alloy reduces the chances of this happening.

Also, this is a good time to note that you are playing with lead. It is not the friendliest heavy metal out there. Always work outdoors or with proper ventilation. Wash your hands. Eat elsewhere.

When soldering, you will often have the need to de-solder something. My favorite tool for this is solder wick. This is a fine braided copper wire saturated with rosin flux. If this is placed over a solder joint and then heated with an iron, it wicks up the solder and removes it from the joint. This is surprisingly clean and easy to do.

 The other option for removing solder from a circuit board is a solder sucker. It is a spring loaded plunger with a Teflon tip that can withstand high temperatures. You compress the plunger until it clicks in place. Then you melt the solder joint, quickly place the tip of the solder sucker into the molten solder, and press the release button on the side. This releases the plunger and the spring pushes it out causing a rapid vacuum action. This sucks the solder right out of the joint... in theory. I haven't had the best luck with this. Sometimes it works for me, sometimes it doesn't. The tip tends to clog with hardened solder and requires occasional cleaning. I tend to prefer the solder wick.

That sums up my arsenal of soldering equipment. Every tool is not necessary, but each has its uses. This is probably a much longer answer than that reader expected from such a simple question, but it turns out that I had quite a bit to say about it.

FrånkenLämp Update

It has been over two months since I committed to posting updates at least every other week.

This has been working rather well for me. It's about time that I updated the banner on the site to reflect this fact. I try to stay a post or two ahead, and I have been occasionally inserting smaller updates on the off-weeks.

This is one of those smaller updates. It is a follow up to the two-part FrånkenLämp story.

Part I inspired this comment:

...You'll laugh, you'll cry, you'll wish it was already Tuesday after next to read part two of the FrånkenLämp adventure. Critics are calling it "the most thrilling quest for accent lighting of our age."

And the conclusion inspired this one:

It's here! The thrilling conclusion to the FrånkenLämp saga. Critics are heralding it as: "Poignant. An accent lighting adventure to end all accent lighting adventures. A coming-of-age lamp tale that is both riveting and thought-provoking."

Both comments were from the person for whom the lamp was being constructed... So she may have been slightly biased...

I am happy to say that she is very happy with it (if you couldn't tell by the comments above). Here is an artfully staged action shot of  FrånkenLämp in its new home:

Useful Power Supply

I enjoy playing around with electronics. One thing that most, if not all, electronics projects need is a good power supply. Some projects are more forgiving than others, but many have strict demands on things like voltages and current.

Obsolete computers tend to provide a wealth of interesting and useful pieces. For example, every computer has a power supply. Most are of a surprisingly high quality. They supply a number of set voltages, usually with the ability to supply a surprisingly high amount of current. They use standardized connectors which can also be scavenged from old computers.

Mine is rated for 28 amps at 3.3 volts, 40 amps at 5 volts, and 30 amps at twelve volts. In comparison, the typical power supply used to charge a cell phone is rated to supply only 1 amp at 5 volts.

Many electronic circuits do not require heaps of current. But that is the beauty of the thing. A circuit will only pull as much current as it needs, and it is convenient to have the excess current available when it is needed. Like when trying to power ridiculously large stepper motors... but that is hopefully the subject of a future post. For now we focus on the power supply.

A computer power supply can be much more cumbersome than is desired for use on an electronics bench. By my count, there are typically somewhere around 50 individual wires sprouting out of the side. More modern versions (ATX) don't even have a power button. They will not turn on unless connected to a computer's motherboard. Conveniently, these limitations and inconveniences can be overcome.

Lets start with turning it on.
There is a 20 pin or 24 pin connector on the power supply. This is how it connects to the motherboard on a computer. One of the wires going to this connector is green. If you connect this wire to ground, the power supply turns on. When you disconnect it, it turns off.

With this knowledge, a switch can be added to turn the power supply on or off. Or, the green wire can be soldered to ground, and the power supply will turn on whenever it is plugged in.

Next, let's get rid of most of those unnecessary wires.
For my purposes, I only left a few of the 4-pin connectors in place. This gives me access to 12 volt (yellow) and 5 volt (red) power. I also left one of the 6 pin connectors in case I needed 3.3 volt (orange) power. With the power supply unplugged, I opened up the case and removed the main circuit board. I then cut off or un-soldered the unneeded wires.

In the picture below, you can see several of the ground wires (black) cut off almost flush with the circuit board. (Above the leftmost corner of the fan, next to the mounting screw.)

An important detail is that there are three feedback wires on the 20 or 24 pin connector. These are smaller diameter wires that connect to the same pins as three of the standard diameter ones. There is one for each of the three main voltages. These must remain connected to their respective supply voltage for the power supply to continue to function. You can see below where I shortened these wires so they would fit inside the case and soldered them to the appropriate supply wires. You can also see some red and orange wires that could not be cut close to the circuit board. These were left longer and the cut ends were insulated with heat-shrink.

The last step I performed was to add some additional connectors.
When prototyping, it is often convenient to be able to supply power to the bare end of a wire. I had the following set of connectors that I rescued from some broken speakers. When you push on the lever, you can insert the end of a wire. When you release, it is held tight. A standard 4-pin female connector was added so that it could easily be plugged in to the power supply. Below are top and bottom views.

I then attached the connectors to the top of the power supply with some double-sided foam tape.

You might note the comment written in Sharpie on the top of the power supply. When using old computer power supplies there are two weak points. One of them is the cooling fan or fans. The fans ran whenever the computer was on, and as a consequence they can be dusty, worn, and noisy. If the fan fails, there is the danger of overheating the power supply. To prevent this, I placed a drop of fresh oil on the fan bearings when I had everything disassembled. This should help preserve them and allow them to continue to cool the power supply. 

The second weak point in some power supplies are the electrolytic capacitors. Due to poor manufacturing, there are many capacitors that fail before they should. Before going through all this trouble, a check should be made that the top of the capacitors in the power supply are not bulged, domed, or leaking. The top should be perfectly flat. 

There are many other how-to articles on the web that discuss re-purposing a computer power supply. The power supply can be modified in a number of ways, depending on your needs.  This is one good example. The author gives a brilliant tip on modifying the fans to run on lower voltages to reduce noise. This is a great idea if you don't plan on using too much current and dislike listening to the whir of a loud fan.

FrånkenLämp Part II

When we last saw this project, everything was disassembled. Now we are going to put FrånkenLämp together.

The metal stalks from TIVED have a slightly larger diameter than the holes in the perforated plate of STRANNE. This required careful drilling of the holes to avoid damaging the densely packed wires. Once the holes were large enough, the three metal stalks were inserted. 

Tie wraps were used to hold the three metal stalks in place. One was snaked around them in the space between the two perforated plates. This was tightened, pulling them together. A second was used just below the bottom perforated plate, holding the ends together and locking them in place. You can see the cut ends of the two tie wraps in the picture above.


Since the ends of the metal stalks extend further, a large hole was drilled in the white plastic cover. This is what it looks like with the modified cover back in place. I didn't quite get the hole centered, luckily it was big enough that everything still fit.


Here you can see what the combined bundle of lights looks like. I was very pleased with how things were coming together.








Now, I just needed to power the thing. Since there were two different types of LED bulbs, each requiring a different voltage, I used both power supplies that came with the two lamps. At this point, I made some modifications that weren't completely necessary. I could have mounted a short power strip inside the lamp or had two separate wires coming out of the base to be plugged in. However, I wanted everything controlled by a single switch, and I didn't want any internal electrical connections that could come loose when the lamp was moved.

So, I opened up each of the power supplies and made soldered connections. This is the first one taken apart.   On the right half of the case are the two contacts that attach to the prongs of the plug hidden beneath. The connector at the bottom center is the DC supply for the LEDs.

 This is what it looked like after I soldered permanent connections to the circuit board. The two tie wraps serve as a strain relief, since they are too large to fit through the hole in the plastic case. This prevents damage to the soldered connections if the wires are pulled.

I did the same thing to the second lamp's power supply, and closed them up with some Gorailla Tape (think Duct Tape, but better) and super glue. I wired the three LED bulbs from the TIVED back together in series and covered everything with more heat-shrink tubing. Below you can see the two power supplies, one for each type of bulb. 

This is the layout of how I mounted things inside the lamp. You can see that there is plenty of room for everything. At the bottom of the picture, you can see the switch built in to the power cord. With the original Ikea design, this would only see low voltage DC power. However, it is clearly marked that it is rated for 120 volts AC and (if I remember correctly) three amps. This is more than sufficient to power both lamps.

A quick test shows everything in working order and a good amount of light.

With everything working, I used some double-sided foam tape to mount the two power supplies inside the lamp.

Then I attached the base... and tried it out for real.

I am extremely happy with the final results. It has the nice soft area lighting from the STRANNE combined with an abundance of usable light from the TIVED. It seems rather perfect, and it is the only one of its kind. 

FrånkenLämp Part I

I was recently introduced to the furniture store known as Ikea. It is a Swedish company, and they have fun with their product names. It is an enjoyable store to wander through, even if you are not looking to buy anything. They have a cafe that serves tasty food, including Swedish meatballs. Also, they have reasonably priced, decent furniture.

In one such afternoon of wandering through the lighting section, a rather attractive lamp was discovered. It was named STRANNE and cost about $50.

It consists of 36 flexible stalks, each tipped with an LED bulb. The only drawback is that it doesn't produce very much light, probably not enough light to read by. This was disappointing. 

Further wandering on a different afternoon uncovered another interesting lamp. This one was named TIVED and cost about $70.

It consists of five flexible metal stalks, each with a much brighter LED bulb. It produced plenty of usable light. The only drawback was that it is ugly and boring in comparison. The need for a lamp remained unfilled. 

Sometime later, inspiration struck. The idea was conceived to combine the two lamps, maintaining the best features of each. Now, you might be thinking that $120 is a lot of money to spend on a lamp, especially a lamp that involves dismantling what was just purchased, voiding all warranties. For a normal lamp, you would be right. But, it is a small price to pay in the quest for the perfect lamp. Plus, it became a fun project and an excuse to take things apart. Count me in!

Fair warning:  this subject is going to be divided into two separate posts. This first will detail the disassembling of STRANNE and TIVED. The second will cover the combination into FrånkenLämp. 

Let us start with STRANNE. 

It is shipped in three pieces. The top portion, middle, and base. This allows it to fit in a surprisingly small package. Here is a picture of the top portion. It contains all the electrical parts. 

Removing the four screws allows the white cover to come off and reveals the ends of the bulb stalks mounted in two perforated plates. It also gives access to the wiring that goes to each of the bulbs. Each bulb is wired in parallel. Crimp connectors join all the individual bulb wires together and connect to the positive and negative wires from the power supply. Wired this way, each bulb runs off of 6 volts from the 6 volt power supply. 

Since everything is in parallel, any number of the bulbs can be removed without affecting the others. For my purposes, I removed three of the bulbs to make way for brighter ones from the TIVED. I chose to place them in the center so that they would not take away from the aesthetics of the lamp. The remaining ends of the wires that were cut to remove the bulbs were covered by heat-shrink tubing to insulate them. 

Here is a close-up view of one of the stalks that was removed. There is a flexible plastic tube on the outside with the wiring running down the middle. The two electrical wires going to the LED bulb are cut short. The long wire, with a hook bent at the end is a stiffer wire. This exists so that when you bend the stalk, it stays where you moved it. This allows you to arrange the lamp in a pleasing manner. The plastic plug at the end is what holds the stalk in place in its designated hole. 

That is the extent of the disassembly of STRANNE. Let us move on to TIVED. 

Three screws hold the plastic cover in place over the base of the lamp. Removing them and the cover reveals the following. There are five bulbs and one resistor. They are wired as two parallel sets. One set has three bulbs in series. The other has two bulbs and the resistor in series. Arranged this way, each bulb runs on about four volts from the 12 volt power supply. 

Because of this arrangement, the choices for reusing the bulbs were limited to using 2, 3, or 5. (The set with the resistor, the set with three bulbs, or both sets together.) Using all five seemed like too much, and just two seemed like not enough. The executive decision was made to use three. Three is not as symmetrical as might be desired, but since they would be buried in the middle of the cluster of bulbs, it was deemed to be an acceptable number.

The metal stalks on this lamp are longer than the ones on the STRANNE, as can be seen below.

The ends of the metal stalks are threaded and formed so that they can be attached to the base. A tubing cutter was used to shorten them to the correct length. This also gave a smooth piece that would more easily fit through the holes in the perforated plates of the STRANNE.

Care was taken not to damage the wires running through the center of the stalks. Two layers of heat-shrink tubing were placed on the wires to protect them from the sharp edge left behind by the tubing cutter.

Here you can see the two different bulbs. On the right is one of the stalks remove from the STRANNE. On the left is one of three metal stalks from the TIVED that has been cut to length.

This is where our story pauses for the moment. Tune in next time for the reassembly.

Managing Podcasts

I use iTunes to manage my podcasts. It works well, but it is vastly improved with the use of live-updating smart playlists.

What pushed me into figuring this out was using my iPod with my car radio. There was no way to tell which podcasts had already been listened to. To make it worse, the radio only displays part of the podcast title at a time, so it was difficult to tell which episode was which.

I set up a playlist for each of the podcasts I subscribe to which only includes episodes that have not been played. That is what makes it "smart."

As soon as an episode is played, it is removed from the playlist. This happens on the iPod automatically, without having to plug it into a computer or sync with iTunes. That is the beauty of live updating.

Here is how to do it:


First, create a new smart playlist by clicking on the File menu and New Smart Playlist...  (Or Ctrl+Alt+N)

Next, set up the two following rules and make sure that "Live updating" is checked.

The first rule is easy, and will be the same for every podcast you want to set up this way:

• Plays is 0

The second rule needs to be something that will filter all the podcast episodes out of your entire music and podcast library. The secret I discovered to make this work with live updating on the iPod, is to only include data in the rules that exists on the iPod itself. You would think that Apple could disable the "Live Updating" checkbox if you choose data fields that won't work with live updating, but you would be wrong, apparently.  Choosing one of the following has worked well for me:

• Artist contains [Artist Name]
• Album contains [Album Name]

It should look like this. 

Note that this requires the artist name to be identical for all episodes of the podcast and unique from the artists of other podcasts or music. This would not work for the two NPR podcasts seen below. Both have NPR as the artist name.

In this case, I used the album name.

Using the new playlists is simple. Just go to "Playlists" on your iPod instead of "Podcasts" when you want to listen. It will show only the new episodes, and they will disappear like magic once they have been listened to. Smart, live-updating magic.