Making Stuff: Improvised C-Cell Batteries

I get a sense of satisfaction, usually far out of proportion with the actual accomplishment, when I manage to achieve some minor technical win in day-to-day life.  One recent example was the creation of improvised C-cell batteries.

We have a Sony shower radio that requires four C-cell batteries, which need to be replaced about every 10 months under normal daily use.  It is, I think, the only device in our house that uses C-Cell batteries anymore.  I end up needing to buy batteries specifically for it every time it needs new batteries.  This last time the batteries died, however, I decided to take advantage of the fact that C cells are the same length as AA, of which we have plenty.  And yes, I know that there are plastic shells into which you can slide a AA battery to make it C-size.  But the same result can ALSO be achieved with strips of cardboard (in this case, cut from 12-pack Coke boxes) wrapped around the battery to achieve the proper outer diameter, and then duct-taped in place.

This is what the finished adapted battery looks like:

And here's the set of four installed in the radio battery compartment:

So, what are the limitations of this approach?  Well, obviously the pseudo-C battery only has the capacity of a AA.  If you look at many rechargeable batteries, however, you will find that the C-cells you can buy often have exactly the same storage capacity as the same brand's AA batteries.  In other words, they are just putting AA cells into C-sized packages.  The reduced capacity battery will only last about half as long as "real" C-cells, but then I can just untape them, unwind the strip of cardboard, and replace the AA at the core.

The peak current sourcing capacity of the AA battery is also less than a C-cell, but unless you're drawing really high current (and this radio just doesn't) this is not a limitation.  Likewise, in applications that draw extremely high currents, the batteries may actually heat up enough due to their heightened internal resistance that cardboard duct-taped around the AA becomes a hazard.  But again, this "transistor radio" application doesn't come anywhere near that level of current draw.

When working on home projects, I often have to decide up front that the amusement value of making something work is far more valuable than the actual fix.  Was it worth the time to measure, cut, roll, and tape cardboard to build adapters when I could have just grabbed the batteries the next time I was at virtually any store?  Of course not!  Did it amuse me, and offer the satisfaction of a hack done entirely with materials I had on hand?   Absolutely!

Writers Do Math, When Necessary

Writers read, a lot, according to several authors whose opinion and craft I respect. Most notably, I remember Dean Koontz in his book on writing talking about the need to read constantly. I also just like to read, because it is entertaining, and fun, expands my vocabulary and world view, gives me things to talk about with friends, and quite honestly, it's easy to do. But it also takes time. And while "I don't have time" is the frequent excuse of people who waste vast amounts of time doing inconsequential things (I'm looking at you, television, FaceBook, Hulu, YouTube, and most of the Internet), it is still hard to muster the 8 - 30 hours that it can take to read a good book.

In order to consume more books, I started listening to books on tape years ago, and I now try to have a constant stream of books on CD from the local library in my car. They're free, they're extremely convenient, and given the limited selection the library can carry, they tend to be only the most popular titles, which are often things I wanted to read anyway. Even with my relatively short commute, I get through at LEAST 30 minutes of "reading" a day, and if you include all other driving, I probably clear about a CD a day on average. That means I can listen to a 15 CD novel in about 2 weeks. Yes, you can argue about the merits of listening to someone read the text versus reading the printed page yourself, but I find the narration usually doesn't get in the way, and the time savings is well worth it.

The latest book I'm listening to is Deception Point by Dan Brown. It's a techno-political thriller that he wrote in 2001, after Angels and Demons, and before The Da Vinci Code. I'm on disk 10 of 15 so far, and the story is okay, although it frequently feels a bit thin in places, like he's milking more pages than are really merited from many of the story elements. But the things that have bugged me the most are engineering related nits which could have been largely avoided with some basic math and physics.

The most glaring has to do with the weight of a rock. I'll attempt not to spoil any of the story here, but several times there are references made to a rock which is initially described as "10 feet in diameter" weighing "eight tons." The rock is described as approximately spherical, which would give it a radius = diameter / 2 = 5 feet. The volume of a sphere is 4/3 * pi * radius^3, which means the rock has an approximate volume of 1.333 * 3.14159 * 5 * 5 *5 = 523.5 cubic feet. Using Google, we can easily convert this to liters and we get 14824 liters. Now, if it were made of WATER, and not rock, that 14,824 liters would weight about 14,824 kilograms = 32681 pounds = about 16 tons. But it's not water, it's ROCK. The rock is described as granite like, which would have a specific gravity, or density relative to water, of about 2.6. This means that it would weight 16 * 2.6 = about 41.6 tons. But even if we say it is the least dense rock we can come up with, pumice stone, the air-filled "floating rock" ejected by volcanoes, it would STILL have a specific gravity of 0.64, and a mass of about 16 * 0.64 = 10 Tons. The "eight tons" sounded wrong when I first read it, and now, especially after doing the math, it grates on me every time it is repeated.

So the follow-up question, of course, is why did this happen? Is there some major plot point I haven't yet gotten to about the rock being only 25% of the weight it should be? Or was it just sloppiness by Dan Brown, and then by his editors? Given how lauded Brown is for his extensive research, it seems strange and jarring that such a relatively obvious factual error made it into the book... And if anyone reading this knows Mr. Brown, I'd love to hear his explanation!

Writers Write

I have long fancied myself a writer, but the volume of my output clearly says otherwise. I tend to worry that I've got a piece polished and shiny and finished to the point that I don't create much of anything. In an effort to break this trend, I am going to start a period of VASTLY accelerated writing. If I manage to pull it off, what you are going to see here in the next month is, I hope, at least one article each day, written in one pass, with only the roughest edges filed off. And of course, all of this will be done within the larger context of work, and family, and all the other ongoing responsibilities that I can't let drop either.

The longer term goal of this effort is to get myself unstuck, to advance several writing projects, both fiction and non-fiction, that I have been incubating for a very long time, and which I finally feel a need to complete. I'm not going to live forever, after all, and I don't want to die with too many of my words still in me. Furthermore, like so many things, the only way to improve my craftsmanship as a writer is to actually do it. Talking about it, thinking about it, pondering the greatness that I could one day shine down upon the world means nothing if I don't get started... and so I am.

If you're reading this, well, skip ahead to the next entry because this is just introductory late night navel-gazing. But if you HAVE read this far, please write a comment, or write me an e-mail, or call me (because if you're here, at least during this development phase in September - October 2010, you almost certainly already know me) and let me know what you think. I gotta work the keyboard, get the words out, keep the cursor moving. It's a cliche but that doesn't mean it's not true: Writers write. And dammit, I wanna be a writer.