Hand-Held DSOs for Industrial Applications

B&KThe 2510 Series hand-held digital storage oscilloscopes (DSOs) includes 60- and 100-MHz bandwidth models in non-isolated and isolated designs. The portable, dual-channel DSOs provide floating measurement capabilities with built-in digital multimeter (DMM) and recorder functions.

Models 2511 and 2512 provide non-isolated 300-V CAT II-rated inputs and are well suited for general electronics. Designed for industrial applications, models 2515 and 2516 provide two fully isolated 1,000-V CAT II/600-V CAT III-rated inputs and feature fully isolated channels for safe and accurate floating measurements.

All 2510 Series models offer 5.7” color displays, a built-in 6,000-count DMM with dedicated terminals for current measurement, and oscilloscope/meter trend plot functions to log measurement values. You can use the DSOs to capture and record up to two voltage or time parameters or graph any of the DMM’s measurements, including DC/AC voltage and current, resistance, capacitance, diode, and continuity testing.

The 2510 Series’ additional features include digital filtering with adjustable limits, 32 automatic measurements, FFT and math functions, a multi-language interface, and USB connectivity for remote PC control. A side-panel USB host port is available to save setups, waveform data, screenshots, or CSV files to a USB flash drive.

Each model weighs approximately 3.4 lb with the included rechargeable lithium-ion battery and can provide up to 4 h of continuous battery operation. The DSOs include two high-bandwidth safety-rated passive probes and a pair of DMM test leads. Models 2515 and 2516 include a hard plastic carry case accessory. The 2510 Series models are backed by a standard three-year warranty. The model 2511 (60 MHz, two non-isolated Ch, 300 V CAT II) costs $935.

The model 2512 (100 MHz, two non-isolated Channel, 300 V CAT II) costs $1,125. The model 2515 (60 MHz, two isolated Channel, 1,000 V CAT II, 600 V CAT III) costs $2,165. The model 2516 (100 MHz, two isolated Channel, 1,000 V CAT II, 600 V CAT III) costs $2,395.

B&K Precision Corp.
www.bkprecision.com

Gordon Margulieux Wins the CC Code Challenge (Week 29)

We have a winner of last week’s CC Weekly Code Challenge, sponsored by IAR Systems! We posted a code snippet with an error and challenged the engineering community to find the mistake!

Congratulations to Gordon Margulieux of Oregon, United States for winning the CC Weekly Code Challenge for Week 29! Gordon will receive an Elektor 2012 & 2011 Archive DVD.

Gordon’s correct answer was randomly selected from the pool of responses that correctly identified an error in the code. Gordon answered:

Line 10: Conditional should be “if (number == 0)” instead of number < 0

2013_code_challenge_29_answer

You can see the complete list of weekly winners and code challenges here.

What is the CC Weekly Code Challenge?
Each week, Circuit Cellar’s technical editors purposely insert an error in a snippet of code. It could be a semantic error, a syntax error, a design error, a spelling error, or another bug the editors slip in. You are challenged to find the error.Once the submission deadline passes, Circuit Cellar will randomly select one winner from the group of respondents who submit the correct answer.

Inspired? Want to try this week’s challenge? Get started!

Submission Deadline: The deadline for each week’s challenge is Sunday, 12 PM EST. Refer to the Rules, Terms & Conditions for information about eligibility and prizes.

Electrical Engineering Crossword (Issue 282)

The answers to Circuit Cellar’s January electronics engineering crossword puzzle are now available.

282-Crossword-key

Across

4.    VENNDIAGRAM—Represents many relation possibilities [two words]
5.    PERSISTRON—Produces a persistent display
9.    CODOMAIN—A set that includes attainable values
12.    HOMOPOLAR—Electrically symmetrical
13.    TRUTHTABLE—Determines a complicated statement’s validity [two words]
17.    POWERCAPPING—Controls either the instant or the average power consumption [two words]
18.    MAGNETRON—The first form, invented in 1920, was a split-anode type
19.    MAGNETICFLUX—F
20.    TURINGCOMPLETE—The Z3 functional program-controlled computer, for example [two words]

Down

1.    CHAOSCOMPUTERCLUB—Well-known European hacker association [three words]
2.    LOGICLEVEL—When binary, it is high and low [two words]
3.    LINEARINTERPOLATION—A simple, but inaccurate, way to convert A/D values into engineering units [two words]
6.    SYNCHRONOUSCIRCUIT—A clock signal ensures this device’s parts are in parallel [two words]
7.    BOARDBRINGUP—Design validation process [three words]
8.    HORNERSRULE—An algorithm for any polynomial order [two words]
10.    MEALY—This machine’s current state and inputs dictate its output values
11.    SQUAREWAVE—It is produced by a binary logic device [two words]
14.    THEREMIN—Its electronic signals can be amplified and sent to a loudspeaker
15.    ABAMPERE—10 A
16.    SCOPEPROBE—Connects test equipment to a DUT [two words]

 

Q&A: Andrew Godbehere, Imaginative Engineering

Engineers are inherently imaginative. I recently spoke with Andrew Godbehere, an Electrical Engineering PhD candidate at the University of California, Berkeley, about how his ideas become realities, his design process, and his dream project. —Nan Price, Associate Editor

Andrew Godbehere

Andrew Godbehere

NAN: You are currently working toward your Electrical Engineering PhD at the University of California, Berkeley. Can you describe any of the electronics projects you’ve worked on?

ANDREW: In my final project at Cornell University, I worked with a friend of mine, Nathan Ward, to make wearable wireless accelerometers and find some way to translate a dancer’s movement into music, in a project we called CUMotive. The computational core was an Atmel ATmega644V connected to an Atmel AT86RF230 802.15.4 wireless transceiver. We designed the PCBs, including the transmission line to feed the ceramic chip antenna. Everything was hand-soldered, though I recommend using an oven instead. We used Kionix KXP74 tri-axis accelerometers, which we encased in a lot of hot glue to create easy-to-handle boards and to shield them from static.

This is the central control belt-pack to be worn by a dancer for CUMotive, the wearable accelerometer project. An Atmel ATmega644V and an AT86RF230 were used inside to interface to synthesizer. The plastic enclosure has holes for the belt to attach to a dancer. Wires connect to accelerometers, which are worn on the dancer’s limbs.

This is the central control belt-pack to be worn by a dancer for CUMotive, the wearable accelerometer project. An Atmel ATmega644V and an AT86RF230 were used inside to interface to synthesizer. The plastic enclosure has holes for the belt to attach to a dancer. Wires connect to accelerometers, which are worn on the dancer’s limbs.

The dancer had four accelerometers connected to a belt pack with an Atmel chip and transceiver. On the receiver side, a musical instrument digital interface (MIDI) communicated with a synthesizer. (Design details are available at http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2007/njw23_abg34/index.htm.)

I was excited about designing PCBs for 802.15.4 radios and making them work. I was also enthusiastic about trying to figure out how to make some sort of music with the product. We programmed several possibilities, one of which was a sort of theremin; another was a sort of drum kit. I found that this was the even more difficult part—not just the making, but the making sense.

When I got to Berkeley, my work switched to the theoretical. I tried to learn everything I could about robotic systems and how to make sense of them and their movements.

NAN: Describe the real-time machine vision-tracking algorithm and integrated vision system you developed for the “Are We There Yet?” installation.

ANDREW: I’ve always been interested in using electronics and robotics for art. Having a designated emphasis in New Media on my degree, I was fortunate enough to be invited to help a professor on a fascinating project.

This view of the Yud Gallery is from the installed camera with three visitors present. Note the specular reflections on the floor. They moved throughout the day with the sun. This movement needed to be discerned from a visitor’s typical movement .

This view of the Yud Gallery is from the installed camera with three visitors present. Note the specular reflections on the floor. They moved throughout the day with the sun. This movement needed to be discerned from a visitor’s typical movement .

For the “Are We There Yet?” installation, we used a PointGrey FireFlyMV camera with a wide-angle lens. The camera was situated a couple hundred feet away from the control computer, so we used a USB-to-Ethernet range extender to communicate with the camera.

We installed a color camera in a gallery in the Contemporary Jewish Museum in San Francisco, CA. We used Meyer Sound speakers with a high-end controller system, which enabled us to “position” sound in the space and to sweep audio tracks around at (the computer’s programmed) will. The Meyer Sound D-Mitri platform was controlled by the computer with Open Sound Control (OSC).

This view of the Yud Gallery is from the perspective of the computer running the analysis. This is a probabilistic view, where the brightness of each pixel represents the “belief” that the pixel is part of an interesting foreground object, such as a pedestrian. Note the hot spots corresponding nicely with the locations of the visitors in the image above.

This view of the Yud Gallery is from the perspective of the computer running the analysis. This is a probabilistic view, where the brightness of each pixel represents the “belief” that the pixel is part of an interesting foreground object, such as a pedestrian. Note the hot spots corresponding nicely with the locations of the visitors in the image above.

The hard work was to then program the computer to discern humans from floors, furniture, shadows, sunbeams, and cloud reflections. The gallery had many skylights, which made the lighting very dynamic. Then, I programmed the computer to keep track of people as they moved and found that this dynamic information was itself useful to determine whether detected color-perturbance was human or not.

Once complete, the experience of the installation was beautiful, enchanting, and maybe a little spooky. The audio tracks were all questions (e.g., “Are we there yet?”) and they were always spoken near you, as if addressed to you. They responded to your movement in a way that felt to me like dancing with a ghost. You can watch videos about the installation at www.are-we-there-yet.org.

The “Are We There Yet?” project opens itself up to possible use as an embedded system. I’ve been told that the software I wrote works on iOS devices by the start-up company Romo (www.kickstarter.com/projects/peterseid/romo-the-smartphone-robot-for-everyone), which was evaluating my vision-tracking code for use in its cute iPhone rover. Further, I’d say that if someone were interested, they could create a similar pedestrian, auto, pet, or cloud-tracking system using a Raspberry Pi and a reasonable webcam.

I may create an automatic cloud-tracking system to watch clouds. I think computers could be capable of this capacity for abstraction, even though we think of the leisurely pastime as the mark of a dreamer.

NAN: Some of the projects you’ve contributed to focus on switched linear systems, hybrid systems, wearable interfaces, and computation and control. Tell us about the projects and your research process.

ANDREW: I think my research is all driven by imagination. I try to imagine a world that could be, a world that I think would be nice, or better, or important. Once I have an idea that captivates my imagination in this way, I have no choice but to try to realize the idea and to seek out the knowledge necessary to do so.

For the wearable wireless accelerometers, it began with the thought: Wouldn’t it be cool if dance and music were inherently connected the way we try to make it seem when we’re dancing? From that thought, the designs started. I thought: The project has to be wireless and low power, it needs accelerometers to measure movement, it needs a reasonable processor to handle the data, it needs MIDI output, and so forth.

My switched linear systems research came about in a different way. As I was in class learning about theories regarding stabilization of hybrid systems, I thought: Why would we do it this complicated way, when I have this reasonably simple intuition that seems to solve the problem? I happened to see the problem a different way as my intuition was trying to grapple with a new concept. That naive accident ended up as a publication, “Stabilization of Planar Switched Linear Systems Using Polar Coordinates,” which I presented in 2010 at Hybrid Systems: Computation and Control (HSCC) in Stockholm, Sweden.

NAN: How did you become interested in electronics?

ANDREW: I always thought things that moved seemingly of their own volition were cool and inherently attention-grabbing. I would think: Did it really just do that? How is that possible?

Andrew worked on this project when computers still had parallel ports. a—This photo shows manually etched PCB traces for a digital EKG (the attempted EEG) with 8-bit LED optoisolation. The rainbow cable connects to a computer’s parallel port. The interface code was written in C++ and ran on DOS. b—The EKG circuitry and digitizer are shown on the left. The 8-bit parallel computer interface is on the right. Connecting the two boards is an array of coupled LEDs and phototransistors, encased in heat shrink tubing to shield against outside light.

Andrew worked on this project when computers still had parallel ports. a—This photo shows manually etched PCB traces for a digital EKG (the attempted EEG) with 8-bit LED optoisolation. The rainbow cable connects to a computer’s parallel port. The interface code was written in C++ and ran on DOS. b—The EKG circuitry and digitizer are shown on the left. The 8-bit parallel computer interface is on the right. Connecting the two boards is an array of coupled LEDs and phototransistors, encased in heat shrink tubing to shield against outside light.

Electric rally-car tracks and radio-controlled cars were a favorite of mine. I hadn’t really thought about working with electronics or computers until middle school. Before that, I was all about paleontology. Then, I saw an episode of Scientific American Frontiers, which featured Alan Alda excitedly interviewing RoboCup contestants. Watching RoboCup [a soccer game involving robotic players], I was absolutely enchanted.

While my childhood electronic toys moved and somehow acted as their own entities, they were puppets to my intentions. Watching RoboCup, I knew these robots were somehow making their own decisions on-the-fly, magically making beautiful passes and goals not as puppets, but as something more majestic. I didn’t know about the technical blood, sweat, and tears that went into it all, so I could have these romantic fantasies of what it was, but I was hooked from that moment.

That spurred me to apply to a specialized science and engineering high school program. It was there that I was fortunate enough to attend a fabulous electronics class (taught by David Peins), where I learned the basics of electronics, the joy of tinkering, and even PCB design and assembly (drilling included). I loved everything involved. Even before I became academically invested in the field, I fell in love with the manual craft of making a circuit.

NAN: Tell us about your first design.

ANDREW: Once I’d learned something about designing and making circuits, I jumped in whole-hog, to a comical degree. My very first project without any course direction was an electroencephalograph!

I wanted to make stuff move on my computer with my brain, the obvious first step. I started with a rough design and worked on tweaking parameters and finding components.

In retrospect, I think that first attempt was actually an electromyograph that read the movements of my eye muscles. And it definitely was an electrocardiograph. Success!

Someone suggested that it might not be a good idea to have a power supply hooked up in any reasonably direct path with your brain. So, in my second attempt, I tried to make something new, so I digitized the signal on the brain side and hooked it up to eight white LEDs. On the other side, I had eight phototransistors coupled with the LEDs and covered with heat-shrink tubing to keep out outside light. That part worked, and I was excited about it, even though I was having some trouble properly tuning the op-amps in that version.

NAN: Describe your “dream project.”

ANDREW: Augmented reality goggles. I’m dead serious about that, too. If given enough time and money, I would start making them.

I would use some emerging organic light-emitting diode (OLED) technology. I’m eyeing the start-up MicroOLED (www.microoled.net) for its low-power “near-to-eye” display technologies. They aren’t available yet, but I’m hopeful they will be soon. I’d probably hook that up to a Raspberry Pi SBC, which is small enough to be worn reasonably comfortably.

Small, high-resolution cameras have proliferated with modern cell phones, which could easily be mounted into the sides of goggles, driving each OLED display independently. Then, it’s just a matter of creativity for how to use your newfound vision! The OpenCV computer vision library offers a great starting point for applications such as face detection, image segmentation, and tracking.

Google Glass is starting to get some notice as a sort of “heads-up” display, but in my opinion, it doesn’t go nearly far enough. Here’s the craziest part—please bear with me—I’m willing to give up directly viewing the world with my natural eyes, I would be willing to have full field-of-vision goggles with high-resolution OLED displays with stereoscopic views from two high-resolution smartphone-style cameras. (At least until the technology gets better, as described in Rainbows End by Vernor Vinge.) I think, for this version, all the components are just now becoming available.

Augmented reality goggles would do a number of things for vision and human-computer interaction (HCI). First, 3-D overlays in the real world would be possible.

Crude example: I’m really terrible with faces and names, but computers are now great with that, so why not get a little help and overlay nametags on people when I want? Another fascinating thing for me is that this concept of vision abstracts the body from the eyes. So, you could theoretically connect to the feed from any stereoscopic cameras around (e.g., on an airplane, in the Grand Canyon, or on the back of some wild animal), or you could even switch points of view with your friend!

Perhaps reality goggles are not commercially viable now, but I would unabashedly use them for myself. I dream about them, so why not make them?

RF Switch for TVs, Set-Top Boxes, and DVRs

PeregrineThe PE42721 is an absorptive 75-Ω single pole, double throw (SPDT) RF switch developed on Peregrine’s UltraCMOSprocess technology. The Peregrine HaRP technology-enhanced switch is well suited for designers of digital TV (DTV) tuner modules, cable TV (CATV) signal switching and distribution systems, multi-tuner DVRs, and set-top boxes.

The switch is ideal for geographic markets (e.g., China, Japan, Korea, and Latin America) where broadband-TV devices must accommodate multiple RF inputs for cable, satellite, and terrestrial reception while avoiding interference among these signals. The PE42721 switch’s isolation is very high; therefore only one tuner chip is needed in each device.
The PE42721 switch pairs the high isolation with low insertion loss, which improves the signal fidelity by reducing the signal-to-noise ratio (SNR). This feature also helps the switch deliver best-in-class linearity and electrostatic-discharge (ESD) performance.

The PE42721 provides isolation of greater than 55 dB across the entire broad-frequency range from 5 MHz to 2.2 GHz. The 3-mm × 3-mm switch supports 1.8- and 3.3-V control logic and RoHS-compliant packaging.

The PE42721 costs $0.45 each in 10,000-unit quantities. Evaluation kit boards cost $95.

Peregrine Semiconductor Corp.
www.psemi.com