About Circuit Cellar Staff

Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at editorial@circuitcellar.com, @circuitcellar, and facebook.com/circuitcellar

New JukeBlox Wi-Fi Platform for Streaming Audio

Microchip Technology’s fourth-generation JukeBlox platform enables product developers to build low-latency systems, such as wireless speakers, sound bars, AV receivers, micro systems, and more. The JukeBlox 4 Software Development Kit (SDK) in combination with the CY920 Wi-Fi & Bluetooth Network Media Module features dual-band Wi-Fi technology, multi-room features, AirPlay and DLNA connectivity, and integrated music services.

Microchip-JukeBlox-Wifi

Streaming audio with JukeBlox

The CY920 module is based on Microchip’s DM920 Wi-Fi Network Media Processor, which features 2.4- and 5-GHz 802.11a/b/g/n Wi-Fi, high-speed USB 2.0 and Ethernet connectivity. By using the 5-GHz band, speakers aren’t impacted by the RF congestion found in the 2.4-GHz band.

The DM920 processor also features integrated dual 300-MHz DSP cores that can reduce or eliminate the need for costly standalone DSP chips. An PC-based GUI simplifies the use of a predeveloped suite of standard speaker-tuning DSP algorithms, including a 15-band equalizer, multiband dynamic range compression, equalizer presets, and a variety of filter types. Even if you don’t have DSP coding experience, you can implement DSP into your designs.

JukeBlox 4 enables you to directly stream cloud-based music services, such as Spotify Connect and Rhapsody, while using mobile devices as remote controls. Mobile devices can be used anywhere in the Wi-Fi network without interrupting music playback. In addition, JukeBlox technology offers cross-platform support for iOS, Android, Windows 8, and Mac, along with a complete range of audio codecs and ease-of-use features to simplify network setup.

The JukeBlox 4 SDK, along with the JukeBlox CY920 module, is now available for sampling and volume production.

Source: Microchip Technology

Lighting and Motor Control Shields for Arduino

Arduino enthusiasts will be excited to learn that Infineon Technologies has announced two new shields for RGB lighting and motor control. You can use the shields—which are compatible to Arduino Uno R3—with the XMC1100 Boot Kit, which is equipped with a 32-bit microcontroller of the XMC1000 family (uses the ARM Cortex-M0 processor).

Infineon-Arduino

Infineon RGB XMC1202 for Arduino

The RGB LED Lighting Shield for Arduino features an XMC1202 microcontroller with its Brightness Color Control Unit (BCCU) for LED lighting control. The high-current DC Motor Control Shield for Arduino contains the Infineon NovalithIC BTN8982TA integrated half-bridge driver for motor control.

The RGB LED Lighting Shield evaluation board enables you to use different LED light engines for fast prototyping. It has three independent output channels for flicker-free control of multicolor LEDs. The BCCU automated hardware engine provides a cost-effective LED lighting solution dimming and color mixing. You can expand the shield with a DMX interface for lighting and audio nodes or a 24-GHz radar sensor for motion detection.

The DC Motor Control Shield with BTN8982TA simplifies the prototyping of DC motor control designs. It can drive two unidirectional DC motors or one bidirectional DC motor. The shield features two NovalithIC BTN8982TA fully integrated high-current half-bridge drivers optimized for motor drive applications. The BTN8982TA includes three ICs: two power chips (one p-channel high-side MOSFET and one n-channel low-side MOSFET) and an integrated driver IC with one logic circuit to control and monitor the power. Other features include are diagnosis with current sense and slew rate adjustment.

Until end of January 2015, both the RGB Lighting Shield with XMC1202 for Arduino and the DC Motor Control Shield with BTN8982TA for Arduino will be available for purchase from Newark element14. After that, they’ll also be available from Infineon and its distributors.

Source: Infineon

B&K Precision Rejuvenates Arbitrary/Function Waveform Generator Line

B&K Precision announced that it rejuvenated the 4075B Series of arbitrary/function waveform generators with higher frequency ranges, increased arb memory, and a color LCD. The new 4075B Series offers six new models that directly replace the previous 4075 line with single- and dual-channel 30-MHz (4075B/4078B) and 50-MHz models (4076B/4079B) along with two additional single- and dual-channel 80-MHz models (4077B/4080B). Each model can generate arbitrary waveforms with 14-bit amplitude resolution, a 200-Msps sample rate, and up to 16,000,000 points (depending on model). These instruments are ideal for use in electronic design, sensor simulation, and functional test.4075B_front

Designed with a dual technology architecture, the 4075B Series combines the benefits of traditional DDS (direct digital synthesis) technology and a true AWG (arbitrary waveform generator). DDS allows standard sine, square, and triangle waveforms to be generated with great frequency resolution at a low cost while the true AWG architecture implements custom arbitrary waveforms with a point-by-point design. This design significantly minimizes jitter and improves signal integrity of the arbitrary waveform.

Similar to their predecessors, the new 4075B Series generators offer a menu-driven front panel keypad with rotary encoder knob and convenient range selection buttons to make adjustments quickly and easily. Additionally, all models provide multi-unit/channel synchronization and external triggering capabilities. For precise triggering at specific points in an arbitrary waveform, users can benefit from the instrument’s fully programmable markers, which allow the unit to generate a positive TTL level signal at a specified waveform address.

The 4075B Series provides eight full memory banks per channel for user-defined arbitrary waveforms and 49 locations to store/recall instrument settings. Arbitrary waveforms can be created from the front panel or loaded using B&K’s free WaveXpress waveform editing software. WaveXpress is a comprehensive stand-alone application that offers several waveform editing tools for users to easily create and load complex arbitrary waveforms onto the AWG via the SCPI-compatible USBTMC or GPIB (50 and 80 MHz models only) interface on the rear.

Other features of the 4075B Series include AM/FM/FSK modulation schemes, linear and logarithmic sweep, and built-in overvoltage and short circuit protection for resistive and capacitive loads on all inputs and outputs to prevent accidental damage to the instrument.

Available immediately, B&K Precision’s 4075B Series products are all backed by a standard 3-year warranty and listed at the following prices ranging from $1,495 (Model 4075B) to $3,690 (Model 4080B).

Source: B&K Precision

 

Low-Jitter 1.25-GSPS Clock Optimizes JESD204B Serial Interface Functionality in GSPS Data Converter Applications

Analog Devices recently introduced the AD9528 JESD204B clock and SYSREF generator defined to support the clock requirements for long-term evolution (LTE) and multicarrier GSM base station designs, defense electronics systems, RF test instrumentation, and more. According to Analog devices, the JESD204B interface was developed “to address high-data rate system design needs, and the AD9528 clock device contains functions that support and enhance the unique capabilities of that interface standard.”

The AD9528 provides a low-power, multi-output, clock distribution function with low-jitter performance, along with an on-chip, two-stage PLL and VCO. The on-chip VCO tunes from 3.6 to 4.0 GHz.

When connected to a recovered system reference clock and a VCXO, the AD9528 generates 12 low-noise outputs with a range of 1 to 400 MHz and two high-speed outputs at up to 1.25 GHz. The frequency and phase of one clock output relative to another clock output can be varied by means of a divider phase-select function that serves as a jitter-free, coarse timing adjustment in increments that are equal to half the period of the signal coming from the VCO output. The SYSREF signals each have additional phase offset capability making it easy to dial-in the optimal arrival time at each target device.

The AD9528 can be designed into wideband RF data acquisition applications with ADI’s AD9680 dual-channel, 14-bit, 1.0-GSPS JESD204B A/D converter.

The AD9528BCPZ costs $8.25 in 1,000-piece quantities. The evaluation board costs $190.

Summit Semiconductor Extended Distance Modules Support WiSA Whole House Audio Specification

Summit Wireless, a division of Summit Semiconductor (from Portland, Oregon), supported the Wireless Speaker and Audio (WiSA) Association demonstrations at the CEDIA Expo 2014 in September. During the show, WiSA announced new multi-zone requirements and feature set for simultaneous support of both wireless home theater playback and multi-zone stereo audio streams. WiSA compliant systems should be able deliver high resolution, uncompressed audio, up to 100 m line of sight or 20 to 40 m through walls.SummitWiSAAmopReferenceDesignWeb

Summit Semiconductor confirms availability of new extended distance transmit and receive modules for those multi-zone home theater and whole home audio applications with support to the WiSA Association’s updated compliance and interoperability test specification.

WiSA members recognize the growth of whole house stereo audio solutions in the market place and the practical need to keep system cost down for mass market acceptance. With the new extended distance radio capabilities, a single system will also provide consumers with a WiSA-compliant home theater system and a whole house system.

The new Summit Semiconductor modules can transmit high quality, uncompressed audio up to 100 m line of site. When integrated in an AVR, audio hub, HDTV, Blu-ray player or gaming console, a single transmit module can manage up 32 speakers, and 8 different zones with separate volume control while simultaneously supporting both home theater and multi-zone audio transport. For example, during the CEDIA Expo the WiSA Association demonstrated a wireless 5.1 home theater system with Summit’s extended distance modules that will also simultaneously transmit a separate stereo pair with different content to a separate location.

The new extended distance modules come pre-certified by country and are backward compatible to the prior generation of Summit’s home theater wireless modules. Engineering samples for the new extended distance modules are available from Summit Semiconductor.

“We’re excited to offer the new extended distance modules in support of the WiSA Association’s multi-zone and whole house initiative,” says Tony Parker, vice president of marketing, Summit Semiconductor. “This is a perfect tool for audio products that need high resolution multi-channel audio, but want to appeal to a broader base as a multi-media whole house platform. Products such as a HDTV, AVR/Pre-amp, game console, soundbar and HTiB can benefit significantly from adding these modules to their designs.”

Source: Summit Semiconductor

Linear Ultrathin 1.8-mm, 3A µModule Regulator

Linear Technology Corp. recently announced the LTM4623 3A µModule (micromodule) step-down regulator in an ultrathin 1.8-mm profile LGA package with only a 6.25 mm × 6.25 mm footprint. With solder paste, the package height is less than 2 mm, meeting the height restrictions of many PCIe, Advanced Mezzanine Cards (AMC) for AdvancedTCA carrier cards in embedded computing systems. The small size and low height allow the LTM4623 to be mounted on the backside of the PCB, freeing space on the topside for components such as memory and FPGAs.linearLTM4623

The LTM4623 operates from 4-to-20-V input supplies and precisely regulates an output voltage from 0.6 to 5.5 V with 1.5% maximum total DC output voltage error. Application examples include ultra-dense data storage, gateway controllers, and 40-to-100-Gbps network equipment.

The LTM4623 solution fits in a 0.5 cm2 dual-sided PCB or less than 1 cm2 on a single-sided PCB. The circuit only requires one input capacitor and one output capacitor, a resistor to set VOUT, and a small capacitor for VOUT tracking and soft-start. With an auxiliary 5-V bias, the LTM4623 operates from input supplies as low as 2.375V. The operating efficiency for converting 12 VIN to 1.5 VOUT and 3.3 VOUT at 3A is 80% and 88%, respectively. Power loss for 12 VIN to 1.5 VOUT is 1.1 W, resulting in only a 24°C rise in junction temperature. The LTM4623 is rated for operation from –40°C to 125°C.

One thousand-piece pricing starts at $6.05 each.

Source: Linear Technology

ARM-based Embedded Power Family for Smart Motor Control

In mid-November 2014, Infineon announced an ARM-based Embedded Power family of bridge drivers offering an unmatched level of integration to address the growing trend towards intelligent motor control for a wide range of automotive applications.  The Embedded Power family offers 32-bit performance in an application space that it is typically associated with 16-bit. Sample quantities of the first members of the Embedded Power family are available for the TLE987x series for three-phase (brushless DC) motors and the TLE986x series for two-phase (DC) motors.Infineon-Embedded-Power-IC_VQFN-48

Infineon combined its proprietary automotive qualified 130-nm Smart Power manufacturing technology with its vast experience in motor control drivers into the new, highly integrated Embedded Power family, available in a standard QFN package of only 7 mm × 7 mm in dimension. Where previous multi-chip designs needed a standalone microcontroller, a bridge driver, and a LIN transceiver, automotive system suppliers now benefit from motor control designs of minimum external components count. The newly released Embedded Power products reduce the component count down to less than 30, thus allowing integration of all functions and associated external components for the motor control in a PCB area of merely 3 cm². As a result, the Embedded Power family enables the integration of electronics close to the motor for true mechatronic designs.

Both the TLE987x and TLE986x bridge drivers use the ARM Cortex TM-M3 processor. Their peripheral set includes a current sensor, a successive approximation 10-bit ADC synchronized with the capture and compare unit (CAPCOM6) for PWM control and 16-bit timers. A LIN transceiver is integrated to enable communication to the devices along with a number of general-purpose I/Os. Both series include an on-chip linear voltage regulator to supply external loads. Their flash memory is scalable from 36 to 128 KB. They operate from 5.4 V up to 28 V. An integrated charge pump enables low-voltage operation using only two external capacitors. The bridge drivers feature programmable charging and discharging current. The patented current slope control technique optimizes the system EMC behavior for a wide range of MOSFETs. The products can withstand load dump conditions up to 40 V while maintaining an extended supply voltage operating down to 3.0V where the microcontroller and the flash memory are fully functional.

The TLE987x series of bridge drivers addresses three-phase (BLDC) motor applications such as fuel pumps, HVAC blowers, engine cooling fans, and water pumps. It supports sensor-less and sensor-based (including field-oriented control) BLDC motor applications addressed by LIN or controlled via PWM.

The TLE986x series is optimized to drive two-phase DC motors by integrating four NFET drivers. The TLE986x series is suitable for applications such as sunroofs, power window lifts and generic smart motor control via NFET H-Bridge.

Engineering samples of the TLE987x and TLE986x bridge drivers in a space-saving VQFN-48 package are available with volume production planned to start in Q1 2015. For both series, there are several derivatives available, differing for example in system clock (24 MHz or 40 MHz) and flash sizes.

Source: Infineon

 

DIY Interactive Robots: An Interview with Erin Kennedy

Erin “RobotGrrl” Kennedy designs award-winning robots. Her RoboBrrd DIY robot-building kit successfully launched in 2012 and was featured in IEEE Spectrum, Forbes, Wired, and on the Discovery Channel. Erin was recognized as  one of the 20 Intel Emerging Young Entrepreneurs. In this interview she tells us about her passion for robotics, early designs, and future plans.5938310667_89a68ca380_o

CIRCUIT CELLAR: How and when did Erin Kennedy become “RobotGrrl?”

ERIN: I used to play an online game, but didn’t want to use my nickname from there. I was building LEGO robots at the time, so my friend suggested “RobotGrrl.” It sounds like a growl without the “ow.”

CIRCUIT CELLAR: Tell us about RobotGrrl.com. Why and when did you decide to start blogging?

ERIN: I started RobotGrrl.com around 2006 to document my adventures into the world of robotics. I would post updates to my project on there, similar to a log book. It helped me gain a community that would follow my adventures.

CIRCUIT CELLAR: Your RoboBrrd company is based on the success of your RoboBrrd beginner robot-building kit, which was funded by Indiegogo in 2012. How does the robot work? What is included in the kit?

ERIN: RoboBrrd works by using three servos, a laser-cut chassis, and an Arduino derivative for its brain. Two of the servos are used for the robot’s wings and the third one is used for the beak mechanism. To construct the chassis, all you need is glue. The brains are on a custom-designed Arduino derivative, complete with RoboBrrd doodles on the silkscreen.

RobotBrrd

RoboBrrd

The first prototype of RoboBrrd was created with pencils and popsicle sticks. Adafruit sent me the electronics and in return I would make weekly videos about building the robot. People seemed to like the robot, so I kept making newer prototypes that would improve on problems and add more to the design.

Eventually I started working on a laser-cut kit version. I won the WyoLum Open Hardware grant and, with the money, I was able to order PCBs I designed for RoboBrrd.

I had enough money for a flight out to California (for RoboGames and Maker Faire Bay Area) where I was an artist in residence at Evil Mad Scientist Laboratories. It was helpful to be able to use their laser cutter right when a new design was ready. Plus, I was able to build a really old and cool Heathkit.

RoboBrrd chassis

RoboBrrd chassis

Afterward, I worked on the design a little more. SpikenzieLabs (www.spikenzielabs.com) helped laser cut it for me and eventually it was all finished. It was such an awesome feeling to finally have a solid design!

In 2012, RoboBrrd launched on Indiegogo and luckily there were enough friends out there who were able to help the project and back it. They were all very enthusiastic about the project. I was really lucky.

Now I am working on a newer version of the 3-D printed RoboBrrd and some iOS applications that use Bluetooth Low Energy (BLE) to communicate with it. The design has come a long way, and it has been fun to learn many new things from RoboBrrd.

CIRCUIT CELLAR: RoboBrrd has had widespread popularity. The robots have been featured on The Discovery Channel, Forbes, MAKE, and WIRED. To what do you attribute your success?

ERIN: The success of RoboBrrd is attributed to everyone who is enthusiastic about it, especially those who have bought a kit or made their own RoboBrrds. It is always fun to see whenever people make modifications to their RoboBrrds.

All I did was make and deliver the kit. It’s all of the “friends of RoboBrrd” who bring their own creative ideas to make it really shine. Also, from the previous question, the readers can see that I had a lot of help along the way.

Having the robots featured on many websites required some luck. You never know if your e-mail pitch is what the journalists are looking for to cover the robot. I was really lucky that websites featured RoboBrrd; it provides it with a little more credibility.

In my opinion, the quirkiness of RoboBrrd helps as well. Sometimes people view it as the “open-source hardware (OSHW) Furby.” It’s a robotic bird and it isn’t your regular wheeled-robot.

CIRCUIT CELLAR: What was the first embedded system you designed. Where were you at the time? What did you learn from the experience?

ERIN: There were systems that I designed using the LEGO Mindstorms RCX 2.0, but my very first design from scratch was a robot called BubbleBoy. The outer appearance looked like a pink snowman. It sat on a green ice cream container and wore a top hat. It was very rudimentary. At the time I was in Grade 11.

Inside of the body sphere were two servos. The servos would push/pull on paper clips that were attached to the head. Inside the head there was a DC motor to spin the top hat around. There was also a smaller DC motor inside the body to attach to a hula hoop to wiggle it. The electronics were enclosed in the container. The robot used an Arduino Diecimila microcontroller board (limited-edition prototype version) and some transistors to control the motors from battery power. There was also a LCD to display the robot’s current mood and water and food levels. On each side of the screen buttons incremented the water or food levels.

There’s a 2009 video of me showing BubbleBoy on Fat Man & Circuit Girl. (Jeri Ellsworth co-hosted the webcast.)

There was not as much documentation online about the Arduino and learning electronics as there is now. I gained many skills from this experience.

The biggest thing I learned from BubbleBoy was how to drive DC motors by using transistors. I also learned how to not mount servos. The hot glue on polystyrene was never rigid enough and kept moving. It was a fun project; the hands-on making of a robot character can really help you kick off making bigger projects.

You can read the entire interview in Circuit Cellar 293 (December 2014).

Workspace for Open-Source Engineering

Christopher Coballes is a Philippines-based freelance R&D engineer and Linux enthusiast with more than a decade of experience in an embedded hardware/software and a passion for an open source design.

The nearby photo shows his home workspace, which includes handy tools such as a spectrum analyzer, digital oscilloscope, and a PCB etcher.

Source: Christopher Coballes

Source: Christopher Coballes

Here are some links to Coballes’s interests and work:

  • Engineering blog
  • Hi-Techno Barrio: A group of Filipino electronics enthusiasts who “aim to uncover the complexity of a modern technology and in turn make it simple, beneficial ,low-cost and free-ware resources.”

View other electrical engineering workspaces.

New Frequency-Programmable, Narrow-Band Transmitter

Leading RF module designer and manufacturer Lemos International/Radiometrix recently launched a new range of flexible, frequency-programmable, RF power adjustable radios. The new NTX2B Transmitter offers industry-leading true Narrow-Band FM performance. It is available on user/factory-programmable custom frequencies between 425 and 470 MHz. Superseding the popular NTX2, the new transmitter offers greater stability and improved performance due to VCTCXO reference. The NTX2B provides users with the ability to dynamically reprogram the module via the microcontroller UART to other channel frequencies in the band or store new frequency/power settings on EEPROM.

Source: Lemos International

Source: Lemos International

The standard NTX2B version is a 10-mW, 25-kHz narrow-band Transmitter with data rates up to 10 kbps and is available on 434.075 and 434.650 MHz European SRD frequencies and 25 mW on 458.700 MHz for the UK. The NTX2B is also available with 12.5- or 20-kHz channel spacing for licensed US FCC Part 90 or legacy European Telemetry/Telecommand bands. The NTX2B features an internal LDO voltage regulator that enables the transmitter to be operated down to 2.9 V and up to 15-V voltage supply at a nominal current consumption of 18 mA and less than 3 µA in power-down mode, which can be enabled within 5 ms. NTX2B can transmit both digital and 3-VPP analog signals. Offering greater range than wideband modules, the transmitter can be paired with the new NRX2B receiver for a usable range of over 500 m, which is ideal for performance-critical, low-power wireless applications, including security, sensor networks, industrial/commercial telemetry and remote control.

Source: Lemos

 

Consumer Interest in Wearables Increases

New consumer research from Futuresource Consulting highlights a significant increase in consumers’ intentions to purchase wearable devices. Interviewing more than 8,000 people in May and and October in the US, the UK, France, and Germany, the study saw interest in fitness trackers and smart watches rise by 50% and 125%, respectively. However, interest in smart glasses and heart rate monitors has stalled.

Source: Futuresource

Source: Futuresource

The overall wearables market has seen significant growth so far in 2014, with Futuresource forecasting full-year sales of over 51 million units worldwide. However, it’s only just warming up, and wearables sales are expected to accelerate from 2015 as new brands enter the space.

The most marked change since May is the strong growth in the number of iPhone owners intending to purchase wearable devices. iPhone owners now lead the way in all categories – particularly in smartwatches, which 17% of iPhone owners expressed an intent to purchase in the next 12 months, up from only 6% in May 2014. This increase coincides with September’s announcement of the Apple Watch. As Apple customers are typically some of the earliest adopters of new technologies, their increasing engagement with the smartwatch category is a strong positive for the Apple Watch release in early 2015.

Source: Futuresource Consulting

Microcontroller-Based Air Quality Mapper

Raul Alvarez Torrico’s Air Quality Mapper is a portable device designed to track levels of CO2 and CO gasses for constructing “Smog Maps” to determine the healthiest routes. Featuring a Renesas RDKRL78G13 development board, the Mapper receives location data from its GPS module, takes readings of the CO2 and CO concentrations along a specific route, and stores the data in an SD card. With the aid of PC utility software, you can upload the data to a web server and see maps of gas concentrations in a web browser.

air q

The portable data logger prototype

In his Circuit Cellar 293 article (December 2014), Torrico notes:

My design, the Air Quality Mapper, is a data-logging, online visualization system comprising a portable data logger and a webserver for the purpose of measuring and visualizing readings of the quality of air in given areas. You take readings over a given route and then upload the data to the server, which in turn serves a webpage containing a graphical representation of all readings using Google Maps technology.

The webpage displaying CO2 measurements acquired in a session

The webpage displaying CO2 measurements acquired in a session

The data logging system features a few key components: a Renesas YRDKRL78G13 development board,  a Polstar PMB-648 GPS module, an SD card, and gas sensors.

The portable data logger hardware prototype is based on the Renesas YRDKRL78G13 development board, which contains a Renesas R5F100LEA 16-bit microcontroller with 64 KB of program memory, 4 KB of data flash memory, and 4 KB of RAM, running from a 12-MHz external crystal…

Air Quality Mapper system

Air Quality Mapper system

The board itself is a bit large for a portable or hand-held device (5,100 x 5,100 mils); but on the other hand, it includes the four basic peripherals I needed for the prototype: a graphic LCD, an SD card slot, six LEDs, and three push buttons for the user interface. The board also includes other elements that could become very handy when developing an improved version of the portable device: a three-axis accelerometer, a temperature sensor, ambient light sensor, a 512-KB serial EEPROM, a small audio speaker, and various connection headers (not to mention other peripherals less appealing for this project: an audio mic, infrared emitter and detector, a FET, and a TRIAC, among other things). The board includes a Renesas USB debugger, which makes it a great entry-level prototyping board for Renesas RL78/G13 microcontrollers.

For the GPS module, I used a Polstar PMB-648 with 20 parallel satellite-tracking channels. It’s advertised as a low-power device with built-in rechargeable battery for backup memory and RTC backup. It supports the NMEA0183 v2.2 data protocol, it includes a serial port interface, and it has a position accuracy 2DRMS of approximately 5 m and velocity accuracy of 0.1 m per second without selective availability imposed. It has an acquisition time of 42 s from a cold start and 1 s from a hot start. It also includes a built-in patch antenna and a 3.3- to 5-V power supply input.

The GPS module provides NMEA0183 V2.2 GGA, GSV, GSA, and RMC formatted data streams via its UART port. A stream comes out every second containing, among other things, latitude, longitude, a timestamp, and date information. In the system, this module connects to the R5F100LEA microcontroller’s UART0 port at 38,400 bps and sources the 3.3-VDC power from the YRDKRL78G13 board.

For the CO2 sensor, I used a Hanwei Electronics Co. MG-811 sensor, which has an electrolyte that in the presence of heat reacts in proportion to the CO2 concentration present in air. The sensor has an internal heating element that needs to be powered with 6 VDC or 6 VAC. For small CO2 concentrations, the sensor outputs a higher voltage, and for high concentrations the output voltage decreases. Because I didn’t have proper calibration instrumentation at hand for this type of sensor, I made a very simple calibration process just by exposing the sensor to a “clean air” environment outside the city. I took an average of various readings in a 15-minute period to define a 400-PPM concentration, which is generally defined as the average for a clean air environment. Not an optimal calibration method of course, but I thought it was acceptable to get some meaningful data for prototyping purposes. For a proper calibration of the sensor, I would’ve needed another CO2 sensing system already calibrated with a high degree of accuracy and a set up in a controllable environment (e.g., a laboratory) in order to generate and measure the amount of CO2.

This sensor provides an output voltage between 30 and 50 mV. And due to their high output impedance, the signal must be properly conditioned with an op-amp. So, I used a Microchip Technology MCP6022 instrumentation amplifier in a noninverting configuration with a gain of 9.2.

You can read the complete article in Circuit Cellar 293 (December 2014).

Liquid Flow Sensor Wins Innovation Prize

Sensirion recently won the DeviceMed OEM-Components innovation prize at the Compamed 2014 exhibition. The disposable liquid flow sensor LD20-2000T for medical devices features an integrated thermal sensor element in a microchip. The pinhead-sized device is based on Sensirion’s CMOSens technology.sensirionliquidflowsensor

The LD20-2000T disposable liquid flow sensor provides liquid flow measurement capability from inside medical tubing (e.g., a catheter) in a low-cost sensor, suitable for disposable applications. As a result, you can measure drug delivery from an infusion set, an infusion pump, or other medical device in real time.

A microchip inside the disposable sensor measures the flow inside a fluidic channel. Accurate (~5%) flow rates from 0 to 420 ml/h and beyond can be measured. Inert medical-grade wetted materials ensure sterile operation with no contamination of the fluid. The straight, open flow channel with no moving parts provides high reliability. Using Sensirion’s CMOSens technology, the fully calibrated signal is processed and linearized on the 7.4 mm2 chip.

Source: Sensirion

Data Center Power & Cost Management

Computers drive progress in today’s world. Both individuals and industry depends on a spectrum of computing tools. Data centers are at the heart of many computational processes from communication to scientific analysis. They also consume over 3% of total power in the United States, and this amount continues to increase.[1]

Data centers service jobs, submitted by their customers, on the data center’s servers, a shared resource. Data centers and their customers negotiate a service-level agreement (SLA), which establishes the average expected job completion time. Servers are allocated for each job and must satisfy the job’s SLA. Job-scheduling software already provides some solutions to the budgeting of data center resources.

Data center construction and operation include fixed and accrued costs. Initial building expenses, such as purchasing and installing computing and cooling equipment, are one-time costs and are generally unavoidable. An operational data center must power this equipment, contributing an ongoing cost. Power management and the associated costs define one of the largest challenges for data centers.

To control these costs, the future of data centers is in active participation in advanced power markets. More efficient cooling also provides cost saving opportunities, but this requires infrastructure updates, which is costly and impractical for existing data centers. Fortunately, existing physical infrastructure can support participation in demand response programs, such as peak shaving, regulation services (RS), and frequency control. In demand-response programs, consumers adjust their power consumption based on real-time power prices. The most promising mechanism for data center participation is RS.

Independent system operators (ISOs) manage demand response programs like RS. Each ISO must balance the power supply with the demand, or load, on the power grid in the region it governs. RS program participants provide necessary reserves when demand is high or consume more energy when demand is lower than the supply. The ISO communicates this need by transmitting a regulation signal, which the participant must follow with minimal error. In return, ISOs provide monetary incentives to the participants.

This essay appears in Circuit Cellar #293 (December 2014).

 
Data centers are ideal participants for demand response programs. A single data center requires a significant amount of power from the power grid. For example, the Massachusetts Green High-Performance Computing Center (MGHPCC), which opened in 2012, has power capacity of 10 MW, which is equivalent to as many as 10,000 homes (www.mghpcc.org). Additionally, some workload types are flexible; jobs can be delayed or sped up within the given SLA.

Data centers have the ability to vary power consumption based on the ISO regulation signal. Server sleep states and dynamic voltage and frequency scaling (DVFS) are power modulation techniques. When the regulation signal requests lower power consumption from participants, data centers can put idle servers to sleep. This successfully reduces power consumption but is not instantaneous. DVFS performs finer power variations; power in an individual server can be quickly reduced in exchange for slower processing speeds. Demand response algorithms for data centers coordinate server state changes and DVFS tuning given the ISO regulation signal.

Accessing data from real data centers is a challenge. Demand response algorithms are tested via simulations of simplified data center models. Before data centers can participate in RS, algorithms must account for the complexity in real data centers.

Data collection within data center infrastructure enables more detailed models. Monitoring aids performance evaluation, model design, and operational changes to data centers. As part of my work, I analyze power, load, and cooling data collected from the MGHPCC. Sensor integration for data collection is essential to the future of data center power and cost management.

The power grid also benefits from data center participation in demand response programs. Renewable energy sources, such as wind and solar, are more environmentally friendly than traditional fossil fuel plants. However, the intermittent nature of such renewables creates a challenge for ISOs to balance the supply and load. Data center participation makes larger scale incorporation of renewables into the smart grid possible.

The future of data centers requires the management of power consumption in order to control costs. Currently, RS provides the best opportunities for existing data centers. According to preliminary results, successful participation in demand response programs could yield monetary savings around 50% for data centers.[2]


[1] J. Koomey, “Growth in Data Center Electricity Use 2005 to 2010,” Analytics Press, Oakland, August, 1, 2010, www.analyticspress.com/datacenters.html.

[2] H. Chen, M. Caramanis, and A. K. Coskun, “The Data Center as a Grid Load Stabilizer,” Proceedings of the Asia and South Pacific Design Automation Conference (ASP-DAC), p. 105–112, January 2014.


LaneTTF Annie Lane studies computer engineering at Boston University, where she performs research as part of the Performance and Energy-Aware Computing Lab (www.bu.edu/peaclab). She received the Clare Boothe Luce Scholar Award in 2014. Annie received additional funding from the Undergraduate Research Opportunity Program (UROP) and Summer Term Alumni Research Scholars (STARS). Her research focuses strategies power and cost optimization strategies in data centers.

 

Probe a Circuit with the Power Off (EE Tip #146)

Imagine something is not working on your surface-mounted board, so you decide use your new oscilloscope. You take the probe scope in your right hand and put it on the microcontroller’s pin 23. Then, as you look at the scope’s screen, you inadvertently move your hand by 1 mm. Bingo!ComponentsDesk-iStock_000036102494Large

The scope probe is now right between pin 23 and pin 24, and you short-circuit two outputs. As a result, the microcontroller is dead and, because you’re unlucky, a couple of other chips are dead too. You just successfully learned Error 22.

Some years ago a potential customer brought me an expensive professional light control system he wanted to use. After 10 minutes of talking, I opened the equipment to see how it was built. My customer warned me to take care because he needed to use it for a show the next day. Of course, I said that he shouldn’t worry because I’m an engineer. I took my oscilloscope probe and did exactly what I said you shouldn’t do. Within 5 s, I short-circuited a 48-V line with a 3V3 regulated wire. Smoke and fire! I transformed each of the beautiful system’s 40 or so integrated circuits into dead silicon. Need I say my relationship with that customer was rather cold for a few weeks?

In a nutshell, don’t ever try to connect a probe on a fine-pitch component when the power is on. Switch everything off, solder a test wire where you need it to be, grab your probe on the wire end, ensure there isn’t a short circuit and then switch on the power. Alternatively, you can buy a couple of fine-pitch grabbers, expensive but useful, or a stand-off to maintain the probe in a precise position. But still don’t try to connect them to a powered board.—Robert Lacoste, CC25, 2013