Gee, maybe it has to do with my consulting business, but our meetings have taken on a decidedly hardware-oriented flavor recently (I create custom computer-controlled hardware; my clients are trade show exhibit designers, industrial and product designers, commercial artists, and so on). In September I showed a video microscope and at our recent October meeting, I got really technical and showed a high-speed oscilloscope with a computer interface.
Scopes
If you don't know what an oscilloscope is, then think of it this way: If a doctor relies on a stethoscope to hear what going on inside a patient's chest, then an electrical engineer relies on an oscilloscope to see what's going on inside an electric circuit. It's a gadget that shows you, graphically, what the voltages in a circuit are doing. Without it, modern technology wouldn't be the same; it's a fundamental tool.
I got interested in electronics in high school, and since then I've used many oscilloscopes, and I've even built one or two (including what is very likely the world's largest working oscilloscope; more on that later).
My first 'scope (as they're called by Those In The Know), was a surplus Tektronix 513D— a huge, power-guzzling monster with a loud fan to cool down its dozens of vacuum tubes. I bought it from my high school electronics teacher, lugged it home, and opened it up to inspect it carefully before I ever plugged it in. I thought that I was being careful, but it darn near killed me.
In high school in the early '70s we still worked with vacuum tubes more than transistors, so I was familiar with high-voltage power supplies. I decided to short out the 'scope's power supply, in order to remove any dangerous electrical charge that might still be lingering in the 'scope. So I put on some rubber kitchen gloves, and I used a screwdriver with a plastic handle to try to short out the high-voltage connection on the CRT (analogous to a picture tube on a TV set). The next thing I knew, I had flown across the room somehow. My mom came in when she heard my gasp (and the thump that I made when I hit the wall). When she saw the 'scope with its case open, she guessed what had happened and was so mad that she almost finished the job that the 'scope had started.
Still, she let me keep the 'scope (after I begged her long enough). But she forbade me from working on it with its case open, and she got a lot tougher about letting me bring home electronic "junk," as she called it.
Even though it had nearly done me in, I cherished that 'scope, and I used it for many years before it finally failed completely. I learned a lot from it (including that very practical lesson about the dangers of a 14,000-volt power supply!).
Fortunately, technology has marched on, and modern 'scopes are smaller, faster, more accurate, and safer (but on the flip side: You often can't repair them yourself because their circuit components are too specialized. But maybe that helps to make them safer, since there's much less incentive to open up a modern 'scope!).
This year my company, Electric Algorithms, Inc., created a huge custom 'scope for the laboratory of a private client. It used more than 5,000 ultra-bright LEDs for its display; they were arranged in a regular matrix about 7 feet wide by 2 feet high. My control circuitry switched the LEDs on and off quickly in order to display information. It used custom software, that I wrote, so that a PC could control the entire display. I've searched quite a bit to see if anybody else has ever made a larger working 'scope; so far, I think mine is the biggest. Of course, size wasn't really the goal; the client wanted an instrument that was unique, attractive, and powerful.
It Takes One to Build One
One of the tools that I used in creating the giant 'scope was another 'scope: a Fluke Model 196. I used it to verify the behavior of the custom circuits that I created for the big 'scope.
The Fluke 196 is a wonderful tool. It's about the size of a hardbound book; it has an LCD screen; it runs on batteries; and it is "digital."
What that means is that when it measures a voltage, it converts the voltage into a digital form before it displays it. In general, that's better than displaying the voltage in its original "analog" form; it's similar to the advantages that a DVD has over an old VHS videotape.
The Fluke is packed with features that make it a very powerful tool in the hands of an experienced user. It can display two voltages simultaneously, and perform various analyses of the voltages. It can display voltages that change very slowly, or very quickly; and it can display voltages that are very small, or very large. It can record the voltages in its memory, for later playback and analysis; and it can "freeze" its display, making it easy to study voltage changes that happen very briefly or infrequently.
Exactly what does this have to do with PCs, anyway?
If you need a permanent copy of a voltage display, you can connect the Fluke to some printers that have a serial interface. Or, you can connect it to a computer, such as a Windows PC, using a special serial cable. Once connected, you can download an image of the display from the Fluke onto your PC. Then you can print the image, e-mail it, etc.
But that's not all: Since the Fluke and the PC have to be able to "talk to" each other (in order to download images), Fluke went further and created software that runs on the PC and sends commands to the Fluke via the serial cable.
The PC is able to control just about all of the Fluke's functions. Fluke provides a Windows program to control the 'scope; they also provide enough technical details that an experienced programmer could create custom programs to control the 'scope.
I won't describe many of the other features of the Fluke 196: it can measure lots of other electrical phenomena; its built-in software can be upgraded by the user without having to open up the 'scope (like upgrading a flash-based BIOS in a PC); it remembers the last settings that you used; and more. It's a great instrument; I think I like it even more than I liked my first old 'scope (and that's saying a lot!).
Flash!
Back in September when I was demonstrating the Intel QX3 video microscope, I mentioned the Fluke. Many of the members present said that they'd like to see it in action, so I demonstrated it at the October meeting connected to my HP OmniBook laptop.
In order to make my demonstration more realistic, I brought along a real electronic circuit to tinker with: the flash unit from a Kodak disposable camera. This is a small circuit board with a flash tube and a few transistors and other parts.
Even though it's designed to be thrown away along with the empty plastic shell of the camera, Kodak did an excellent job designing the circuit. It's optimized to run from a single AA alkaline battery— the ordinary kind used in many electronic gadgets. That one battery gives many, many flashes; typically, dozens more than you need for the camera's built-in single roll of film.
In addition to lots of flashes, the circuit gives lots of voltage. I hooked the Fluke 'scope up to it, and used my PC to show how the circuit works.
The circuit chops up the 1.5 volts from the battery, and boosts it to about 10 volts. The chopping (technically, the "oscillating") happens at about 12,000 cycles per second; that's what makes the high-pitched whine that you can hear while the flash unit is charging up.
The 10-volt oscillating signal is passed to a "transformer" that further boosts it to almost 900 volts; that voltage gets smoothed out ("filtered") and stored in a "capacitor" until you press the button to take a picture. The capacitor acts like a short-term battery, holding electrical charge at about 300 volts.
When you press the button, much of the electrical charge gets dumped into the flash tube, producing an intense, brief flash of light.
Danger, Will Robinson!
Those voltages are nothing to sneeze at; you need to be very careful if you open up one of these little cameras! In fact, even after you have taken the last picture, and even if you have removed the battery, the circuit is quite dangerous, because the capacitor may still contain quite a bit of electrical charge; it does not all get used up when the flash goes off; and it can stay stored in the capacitor for many days, waiting to zap you. Don't tinker with this kind of circuit, and don't open up disposable cameras, camera flash units, or strobe lights, unless you know how to safely work with high voltages, and you take all the necessary precautions! You've been warned; 'nuff said!
I made it through the demonstration without getting zapped, thanks to a lot of experience and care. It was a good way to show off the Fluke ScopeMeter 196, one of my favorite tools.
More USB Minidrives, both Solid State and Mechanical
We saw some other hardware at our meeting: Several members brought in their portable, removable "USB mini-drives." These come in two flavors: solid-state "pen-drives" that use flash memory chips and plug right into your USB port; and mechanical hard drives in external cases. We saw examples of both.
The flash-based pen-drives are now sold by close to a dozen vendors. Most of them are very similar; it's a good idea to peruse the popular PC hardware magazines to look for comparative reviews. Recommended features include: An internal LED that lights up to show activity; a switch to write-protect the drive; and security software that, at the least, uses a password to restrict access to the files on the drive, and perhaps even hides part of the drive completely.
Prices are dropping fast for these pen-drives; large local vendors are selling them regularly for 50 cents per megabyte, and even less on sale.
Mechanical hard drives are rarer, bigger, more expensive, and less rugged. Of course, they hold much, much more than a flash-based pen-drive, since they use a magnetic hard drive; so the cost per megabyte is much lower (even though they are more expensive than the pen-drives, in total cost).
We saw one example from Pocketec; it was smaller than a paperback book. We were told that the manufacturer recommends that you keep it in its padded carrying case at all times, even when it is running.
Both the flash and the mechanical USB drives are automatically recognized by most recent flavors of Windows; you can plug them into a PC and expect them to just work. In that regard, they are just as convenient as floppy disks; perhaps the industry pundits are correct when they predict that these USB drives will replace floppy disks drives entirely— sometime in the future.
The security software is not an automatic part of Windows; but some of the drives that feature this option come with the drivers on the drive, so it is easy to install the security software on any computer that you plug the drive into.
It's nice to see something new and successful, like USB drives, in this jaded old PC world; I hope to keep finding more new things to report on.
Special Holiday Meeting Schedule
As usual, we will be combining our November and December Chapter meetings into one meeting in early December, in order to make room for the holidays.
We will meet on Wednesday, December 11, at 7:00 p.m. in the large meeting room at the Davis public library. We will NOT meet in November, and we will NOT meet on the fourth Wednesday of December.
After that, our January meeting will be held on the fourth Wednesday of January, 2003, at our regular time and place.
Whenever and wherever we meet, you're welcome to attend!
—
Tim Feldman
