Issue 262: Advances in Measurement & Sensor Tech

As I walked the convention center floor at the 2012 Design West conference in San Jose, CA, it quickly became clear that measurement and sensor technologies are at the forefront of embedded innovation. For instance, at the Terasic Technologies booth, I spoke with Allen Houng, Terasic’s Strategic Marketing Manager, about the VisualSonic Studio project developed by students from National Taiwan University. The innovative design—which included an Altera DE2-115 FPGA development kit and a Terasic 5-megapixel CMOS sensor (D5M)—used interactive tokens to control computer-generated music. Sensor technology figured prominently in the design. It was just one of many exciting projects on display.

In this issue, we feature articles on a variety of measurement-and sensor-related embedded design projects. I encourage you to try similar projects and share your results with our editors.

Starting on page 14, Petre Tzvetanov Petrov describes a multilevel audible logical probe design. Petrov states that when working with digital systems “it is good to have a logical probe with at least four levels in order to more rapidly find the node in the circuit where things are going wrong.” His low-cost audible logical probe indicates four input levels, and there’s an audible tone for each input level.

Matt Oppenheim explains how to use touch sensors to trigger audio tags on electronic devices (p. 20). His design is intended to help visually impaired users. But you can use a few capacitive-touch sensors with an Android device to create the application of your choice.

The portable touch-sensor assembly. The touch-sensor boards are mounted on the back of a digital radio, connected to a IOIO board and a Nexus One smartphone. The Android interface is displayed on the phone. (Source: M. Oppenheim)

Two daisy-chained Microchip Technology mTouch boards with a battery board providing the power and LED boards showing the channel status. (Source: M. Oppenheim)

Read the interview with Lawrence Foltzer on page 30 for a little inspiration. Interestingly, one of his first MCU-based projects was a sonar sensor.

The impetus for Kyle Gilpin’s “menU” design was a microprocessor-based sensor system he installed in his car to display and control a variety of different sensors (p. 34).

The design used to test the menU system on the mbed processor was intentionally as simple as possible. Four buttons drive the menu system and an alphanumeric LCD is used to display the menu. Alternatively, one can use the mbed’s USB-to-serial port to connect with a terminal emulator running on a PC to both display and control the menu system. (Source: K. Gilpin)

The current menU system enables Gilpin to navigate through a hierarchical set of menu items while both observing and modifying the parameters of an embedded design.

The menU system is generic enough to be compiled for most desktop PCs running Windows, OSX, or Linux using the Qt development framework. This screenshot demonstrates the GUI for the menU system. The menu itself is displayed in a separate terminal window. The GUI has four simulated LEDs and one simulated photocell all of which correspond to the hardware available on the mbed processor development platform. (Source: K. Gilpin)

The final measurement-and-sensor-related article in this issue is columnist Richard Wotiz’s “Camera Image Stabilization” (p. 46). Wotiz details various IS techniques.

Our other columnists cover accelerated testing (George Novacek, p. 60), energy harvesting (George Martin, p. 64), and SNAP engine versatility (Jeff Bachiochi, p. 68).

Lastly, I’m excited to announce that we have a new columnist, Patrick Schaumont, whose article “One-Time Passwords from Your Watch” starts on page 52.

The Texas Instruments eZ430 Chronos watch displays a unique code that enables logging into Google’s Gmail. The code is derived from the current time and a secret value embedded in the watch. (Source: P. Schaumont)

Schaumont is an Associate Professor in the Bradley Department of Electrical and Computer Engineering at Virginia Tech. His interests include embedded security, covering hardware, firmware, and software. Welcome, Patrick!

Circuit Cellar 262 (May 2012) is now available.

Weekly Elektor Wrap Up: Laser, Digital Peak Level Meter, & “Wolverine” MCU

It’s Friday, so it’s time for a review of Elektor news and content. Among the numerous interesting things Elektor covered this week were a laser project, a digital peak level meter for audio engineering enthusiasts, and an exciting new ultra-low-power MCU.

Are you an embedded designer who wants to start a laser project? Read about “the world’s smallest laser”:

What is the biggest constraint in creating tiny lasers? Pump power. Yes sir, all lasers require a certain amount of pump power from an outside source to begin emitting a coherent beam of light and the smaller a laser is, the greater the pump power needed to reach this state. The laser cavity consists of a tiny metal rod enclosed by a ring of metal-coated, quantum wells of semiconductor material. A team of researchers from the University of California has developed a technique that uses quantum electrodynamic effects in coaxial nanocavities to lower the amount of pump power needed. This allowed them to build the world’s smallest room-temperature, continuous wave laser. The whole device is only half a micron in diameter (human hair has on average a thickness of 50 micron).

The nanolaser design appears to be scalable – meaning that they could be shrunk to even smaller sizes – an important feature that would make it possible to harvest laser light from even smaller structures. Applications for such lasers could include tiny biochemical sensors or high-resolution displays, but the researchers are still working out the theory behind how these tiny lasers operate. They would also like to find a way to pump the lasers electrically instead of optically.

Be sure to check out Elektor’s laser projection project.

In other news, Elektor reached out to audio engineering-minded audio enthusiasts and presented an interesting project:

Are you an audio amateur hobbyist or professional? Do you try to avoid clipping in your recordings? To help you get your audio levels right, in January 2012 Elektor published a professional-quality peak level meter featuring 2x 40 LEDs, controlled by a powerful digital signal processor (DSP). As part of the eight-lesson course on Audio DSP, all the theory behind the meter was explained, and the accompanying source code was made available as a free download.

The DSP Board has been available for a while, and now we are proud to announce that the Digital Peak Level Meter is available as an Elektor quality kit for you to build. Although the meter was designed as an extension module for the Audio DSP board, it can be used with any microcontroller capable of providing SPI-compatible signals. So get your Peak Level Meter now and add a professional touch to your recording studio!

And lastly, on the MCU front, Elektor ran interesting piece about the Texas Instruments “Wolverine,” which should be available for sampling in June 2012:

Codenamed “Wolverine” for its aggressive power-saving technology, the improved ultra-low-power MSP430 microcontroller platform from Texas Instruments offers at least 50 % less power consumption than any other microcontroller in the industry: 360 nA real-time clock mode and less than 100 µA/MHz active power consumption. Typical battery powered applications spend as much as 99.9 % of their time in standby mode; Wolverine-based devices can consume as little as 360 nA in standby mode, more than doubling battery life.

Wolverine’s low power performance is made possible by using one unified ferromagnetic RAM (FRAM) for code and data instead of traditional Flash and SRAM memories, allowing them to consume 250 times less energy per bit compared to Flash- and EEPROM-based microcontrollers. Power consumption is further reduced thanks to an ultra low leakage  process technology that offers a 10x improvement in leakage and optimized mixed signal capabilities.

MSP430FR58xx microcontrollers based on the Wolverine technology platform will be available for sampling in June 2012.

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