- The IoT Events site is an easy-to-use resource for find IoT events and meet-ups around the world.
- The Internet of Things Conference is a resource for information relating to “IoT applications, IoT solutions, IoT example and m2m opportunities in smart cities, connected cars, smart grids, consumer electronics and mobile healthcare.”
- The IoT Counsel website includes useful info such as bios and contact info for engineers, innovators, and thinkers working on IoT-related projects.
- Michael Chui, Markus Loffler, and Roger Roberts present a comprehensive article on IoT in the McKinsey Quarterly. While this isn’t a design-centric document, you’ll find it’s an interesting in-depth overview of the technology and its applications.
- The Business Leaders Network (BLN) has a page on the IoT. The most recent IoT even took place in June, but the site still has some interesting info about speakers, partners, and more.
MIXED SIGNAL OSCILLOSCOPE WITH PROTOCOL ANALYZER
The USBee QX is a PC-based mixed-signal oscilloscope (MSO) integrated with a protocol analyzer utilizing USB 3.0 and Wi-Fi technology. The highly integrated, 600-MHz MSO features 24 digital channels and four analog channels.
With its large 896-Msample buffer memory and data compression capability, the USBeeQX can capture up to 32 days of traces. It displays serial or parallel protocols in a human-readable format, enabling developers to find and resolve obscure and difficult defects. The MOS includes popular serial protocols (e.g., RS-232/UARTs, SPI, I2C, CAN, SDIO, Async, 1-Wire, and I2S), which are typically costly add-ons for benchtop oscilloscopes. The MOS utilizes APIs and Tool Builders that are integrated into the USBee QX software to support any custom protocol.
The USBee QX’s Wi-Fi capability enables you set up testing in the lab while you are at your desk. The Wi-Fi capability also creates electrical isolation of the device under test to the host computer.
The USBee QX costs $2,495.
FREE PCB DESIGN SOFTWARE SUITE
FabStream is an integrated PCB design and manufacturing solution designed for the DIY electronics market, including small businesses, start-ups, engineers, inventors, hobbyists, and other electronic enthusiasts. FabStream consists of free SoloPCB Design software customized to each manufacturing partner in the FabStream network.
The FabStream service works in three easy steps. First, you log onto the FabStream website (www.fabstream.com), select a FabStream manufacturing partner, and download the free design software. Next, you create PCB libraries, schematics, and board layouts. Finally, the software leads you through the process of ordering PCBs online with the manufacturer. You only pay for the PCBs you purchase. Because the service is mostly Internet-based, FabStream can be accessed globally and is available 24/7/365.
FabStream’s free SoloPCB Design software includes a commercial-quality schematic capture, PCB layout, and autorouting in one, easy-to-use environment. The software is customized to each manufacturing partner. All of the manufacturer’s production capabilities are built into SoloPCB, enabling you to work within the manufacturers’ constraints. Design changes can be made and then verified through an integrated analyzer that uses a quick pass/fail check to compare the modification to the manufacturer’s rules.
SoloPCB does not contain any CAM outputs. Instead, a secure, industry-standard IPC-2581 manufacturing file is automatically extracted, encrypted, and electronically routed to the manufacturer during the ordering process. The IPC-2581 file contains all the design information needed for manufacturing, which eliminates the need to create Gerber and NC drill files.
FabStream is available as a free download. More information can be found at www.fabstream.com
DownStream Technologies, LLC
HIGH-PERFORMANCE VECTOR SIGNAL GENERATOR
The R&S SMW200A high-performance vector signal generator combines flexibility, performance, and intuitive operation to quickly and easily generate complex, high-quality signals for LTE Advanced and next-generation mobile standards. The generator is designed to simpify complex 4G device testing.
With its versatile configuration options, the R&S SMW200A’s range of applications extends from single-path vector signal generation to multichannel multiple-input and multiple-output (MIMO) receiver testing. The vector signal generator provides a baseband generator, a RF generator, and a real-time MIMO fading simulator in a single instrument.
The R&S SMW200A covers the100 kHz-to-3-GHz, or 6 GHz, frequency range, and features a 160-MHz I/Q modulation bandwidth with internal baseband. The generator is well suited for verification of 3G and 4G base stations and aerospace and defense applications.
The R&S SMW200A can be equipped with an optional second RF path for frequencies up to 6 GHz. It can have a a maximum of two baseband and four fading simulator modules, providing users with two full-featured vector signal generators in a single unit. Fading scenarios, such as 2 × 2 MIMO, 8 × 2 MIMO for TD-LTE, and 2 × 2 MIMO for LTE Advanced carrier aggregation, can be easily simulated.
Higher-order MIMO applications (e.g., 3 × 3 MIMO for WLAN or 4 × 4 MIMO for LTE-FDD) are easily supported by connecting a third and fourth source to the R&S SMW200A. The R&S SGS100A are highly compact RF sources that are controlled directly from the front panel of the R&S SMW200A.
The R&S SMW200A ensures high accuracy in spectral and modulation measurements. The SSB phase noise is –139 dBc (typical) at 1 GHz (20 kHz offset). Help functions are provided for additional ease-of-use, and presets are provided for all important digital standards and fading scenarios. LTE and UMTS test case wizards simplify complex base station conformance testing in line with the 3GPP specification.
Contact Rohde & Schwarz for pricing.
Rohde & Schwarz
INTEGRATED ZIGBEE SINGLE-CHIP SOLUTION WITH AN ARM CORTEX-M3 MCU
The Texas Instruments (TI) CC2538 system-on-chip (SoC) is designed to simplify the development of ZigBee wireless connectivity-enabled smart energy infrastructure, home and building automation, and intelligent lighting gateways. The cost-efficient SoC features an ARM Cortex-M3 microcontroller, memory, and hardware accelerators on one piece of silicon. The CC2538 supports ZigBee PRO, ZigBee Smart Energy and ZigBee Home Automation and lighting standards to deliver interoperability with existing and future ZigBee products. The SoC also uses IEEE 802.15.4 and 6LoWPAN IPv6 networks to support IP standards-based development.
The CC2538 is capable of supporting fast digital management and features scalable memory options from 128 to 512 KB flash to support smart energy infrastructure applications. The SoC sustains a mesh network with hundreds of end nodes using integrated 8-to-32-KB RAM options that are pin-for-pin compatible for maximum flexibility.
The CC2538’s additional benefits include temperature operation up to 125°C, optimization for battery-powered applications using only 1.3 uA in Sleep mode, and efficient processing for centralized networks and reduced bill of materials cost through integrated ARM Cortex-M3 core.
The CC2538 development kit (CC2538DK) provides a complete development platform for the CC2538, enabling users to see all functionality without additional layout. It comes with high-performance CC2538 evaluation modules (CC2538EMK) and motherboards with an integrated ARM Cortex-M3 debug probe for software development and peripherals including an LCD, buttons, LEDs, light sensor and accelerometer for creating demo software. The boards are also compatible with TI’s SmartRF Studio for running RF performance tests. The CC2538 supports current and future Z-Stack releases from TI and over-the-air software downloads for easier upgrades in the field.
The CC2538 is available in an 8-mm x 8-mm QFN56 package and costs $3 in high volumes. The CC2538 is also available through TI’s free sample program. The CC2538DK costs $299.
Texas Instruments, Inc.
During his June 5 keynote address at they 2013 Sensors Expo in Chicago, Joseph Paradiso presented details about some of the innovative embedded sensor-related projects at the MIT Media Lab, where he is the Director of the Responsive Environments Group. The projects he described ranged from innovative ubiquitous computing installations for monitoring building utilities to a small sensor network that transmits real-time data from a peat bog in rural Massachusetts. Below I detail a few of the projects Paradiso covered in his speech.
Managed by the Responsive Enviroments group, the DoppelLab is a virtual environment that uses Unity 3D to present real-time data from numerous sensors in MIT Media Lab complex.
Paradiso explained that the system gathers real-time information and presents it via an interactive browser. Users can monitor room temperature, humidity data, RFID badge movement, and even someone’s Tweets has he moves throughout the complex.
Paradiso demoed the Living Observatory project, which comprises numerous sensor nodes installed in a peat bog near Plymouth, MA. In addition to transmitting audio from the bog, the installation also logs data such as temperature, humidity, light, barometric pressure, and radio signal strength. The data logs are posted on the project site, where you can also listen to the audio transmission.
The GesturesEverywhere project provides a real-time data stream about human activity levels within the MIT Media Lab. It provides the following data and more:
- Activity Level: you can see the Media Labs activity level over a seven-day period.
- Presence Data: you can see the location of ID tags as people move in the building
The following video is a tracking demo posted on the project site.
The aforementioned projects are just a few of the many cutting-edge developments at the MIT Media Lab. Paradiso said the projects show how far ubiquitous computing technology has come. And they provide a glimpse into the future. For instance, these technologies lend themselves to a variety of building-, environment-, and comfort-related applications.
“In the early days of ubiquitous computing, it was all healthcare,” Paradiso said. “The next frontier is obviously energy.”
Last week at the 2013 Sensors Expo in Chicago, Anaren had interesting wireless embedded control systems on display. The message was straightforward: add an Anaren Integrated Radio (AIR) module to an embedded system and you’re ready to go wireless.
Bob Frankel of Emmoco provided a embedded mobile control demonstration. By adding an AIR module to a light control system, he was able to use a tablet as a user interface.
In a separate demonstration, Anaren electrical engineer Mihir Dani showed me how to achieve effective light control with an Anaren 2530 module and TI technology. The module is embedded within the light and compact remote enables him to manipulate variables such as light color and saturation.
Visit Anaren’s website for more information.
The iC-TW8 is a high-resolution signal processor designed to evaluate sine/cosine sensors. Its automatic functions help minimize angular errors and jitters. The processor can be used for initial, push-button calibration and to permanently adapt signal-path parameters during operation. The angular position is calculated at a programmable resolution of up to 65,536 increments per input cycle and output as an indexed incremental signal. A 32-bit word, which includes the counted cycles, is available through the SPI.
As an application-specific DSP, the iC-TW8 has two ADCs that simultaneously sample at a 250-ksps rate, fast CORDIC algorithms, special signal filters, and an analog front end with differential programmable gate amplifier (PGA) inputs that accepts typical magnetic sensor signals from 20 mVPP and up. Signal frequencies of up to 125 kHz enable high rotary and linear speeds for position measuring devices and are processed at a 24-µs constant latency period.
The device’s 12-bit measurement accuracy works with one button press. Measuring tools are not required. The iC-TW8 independently acquires information about the signal corrections needed for offset, amplitude, and phase errors and stores them in an external EEPROM.
The iC-TW8 has two configuration modes. Preset functions and interpolation factors can be retrieved through pins and the device can be calibrated with a button push. No programming is required for initial operation.
The device’s functions—including an AB output divider for fractional interpolation, an advanced signal filter to reduce jitter, a table to compensate for signal distortion, and configurable monitors for errors and signal quality—can be accessed when the serial interfaces are used. Typical applications include magnetic linear displacement measuring systems, optical linear scales, programmable magnetic/optical incremental encoders, high-resolution absolute/incremental angle sensors with on-axis, Hall scanning, and the general evaluation of sine/cosine signals (e.g., PC measuring cards for 1 VPP and 11 µAPP).
The iC-TW8 operates on a 3.1-to-5.5-V single-ended supply within a –40°C-to-125°C extended operating temperature range. It comes in a 48-pin QFN package that requires 7 mm × 7 mm of board space. A ready-to-operate demo board is available for evaluation. An optional PC operating program, in other words, a GUI, can be connected with a USB adapter.
The iC-TW8 costs $7.69 in 1,000-unit quantities.
The AD9675 and the AD9674 are the latest additions to Analog Devices’s octal ultrasound receiver portfolio. The devices and are pin compatible with the AD9670/AD9671.
The AD9675 is an eight-channel ultrasound analog front end (AFE) with an on-chip radio frequency (RF) decimator and Analog Devices’s JESD204B serial interface. It is designed for mid- to high-end portable and cart-based medical and industrial ultrasound systems. The device integrates eight channels of a low-noise amplifier, a variable-gain amplifier, an anti-aliasing filter, and a 14-bit ADC with a 125-MSPS sample rate and a 75-dB signal-to-noise ratio (SNR) performance for enhanced ultrasound image quality. The on-chip RF decimator enables the ADC to be oversampled, providing increased SNR for improved image quality while maintaining lower data I/O rates. The 5-Gbps JESD204B serial interface reduces ultrasound system I/O data routing.
The AD9674 offers similar functionality, but includes a standard low-voltage differential signaling (LVDS) interface. Both devices are available in a 144-ball, 10-mm × 10-mm ball grid array (BGA) package.
The AD9674 and the AD9675 cost $62 and $68, respectively.
Analog Devices, Inc.
LOW-VOLTAGE DIGITAL OUTPUT HALL-EFFECT SENSORS
MLX92212 digital output Hall-effect sensors are AEC-Q100-qualified devices that deliver robust, automotive-level performance. The MLX92212LSE-AAA low-hysteresis bipolar latch and the MLX92212LSE-ABA high-hysteresis unipolar switch are optimized for 2.5-to-5.5-V operation. They pair well with many low-power microcontrollers in embedded systems. The sensor and specified microcontroller can share the same power rail. The sensors’ open-drain outputs enable simple connectivity with CMOS/TTL. They exhibit minimal magnetic switch point drift over temperature (up to 150°C) or lifetime and can withstand 8 kV electrostatic discharge.
The MLX92212LSE-AAA is designed for use with multipole ring magnets or alternating magnetic fields. It is well suited for brushless DC electric motor commutation, speed sensing, and magnetic encoder applications. Typical automotive uses include anti-trap/anti-pinch window lift controls, automatic door/hatch systems, and automatic power seat positioning. The MLX92212LSE-ABA enables the use of generic/weak magnets or larger air gaps. It can be used in simple magnetic proximity sensing and interlocks in covers/hatches or ferrous-vane interrupt sensors for precise position and timing applications.
Both MLX92212 devices utilize chopper-stabilized amplifiers with switched capacitors. The CMOS technology makes this technique possible and contributes to the sensors’ low current consumption and small chip size.
The MLX92212 sensors cost $0.35 each in 5,000-unit quantities and $0.30 in 10,000-unit quantities.
Melexis Microelectronic Integrated Systems
POWERFUL SPI ADAPTERS
The SPI Storm 50 and the SPI Storm 10 are the latest versions of Byte Paradigm’s SPI Storm serial protocol host adapter. The adapters support serial peripheral interface (SPI), Quad-SPI, and custom serial protocols in the same USB device.
The SPI Storm 50 and the SPI Storm 10 support serial protocols and master up to 50 and 10 MHz, respectively. The SPI Storm 10 features an 8-MB memory, while the higher-end devices are equipped with a 32-MB memory.
The SPI Storm adapters enable system engineers to access, communicate, and program their digital board and digital ICs, such as field-programmable gate array (FPGA), flash memories, application-specific integrated circuit (ASIC), and
system-on-a-chip (SoC). The SPI Storm 10 is well suited for engineering schools and universities because it is a flexible, all-around access device for hands-on digital electronics. The 50- and 100-MHz versions can be used in mid- and high-end testing and debugging for telecommunications, medical electronics, and digital imaging industries.
The SPI Storm 50 and the SPI Storm 10 cost $530 and $400, respectively.
ANALOG-BASED POWER MANAGEMENT CONTROLLER WITH INTEGRATED MCU
The MCP19111 digitally enhanced power analog controller is a new hybrid, digital and analog power-management device. In combination with the expanded MCP87xxx family of low-figure-of-merit (FOM) MOSFETs, it supports configurable, high-efficiency DC/DC power-conversion designs for many consumer and industrial applications.
The MCP19111 controller, which operates at 4.5 to 32 V, integrates an analog-based PWM controller with a fully functional flash-based microcontroller. This integration offers the flexibility of a digital solution with the speed, performance, and resolution of an analog-based controller.
The MCP19111 devices have integrated MOSFET drivers configured for synchronous, step-down applications. The MCP87018, MCP87030, MCP87090, and MCP87130 are 25-V-rated, 1.8-, 3-, 9-, and 13-mΩ logic-level MOSFETs that are specifically optimized for switched-mode-power-supply (SMPS) applications.
The MCP19111 evaluation board includes Microchip’s high-speed MOSFETs. This evaluation board includes standard firmware, which is user-configurable through an MPLAB X IDE graphical user interface (GUI) plug-in. The combined evaluation board, GUI, and firmware enable power-supply designers to configure and evaluate the MCP19111’s performance for their target applications.
The MCP19111 controllers cost $2.81 each and the MCP87018/030/090/130 MOSFETs cost $0.28 each, all in 5,000-unit quantities.
Microchip Technology, Inc.
ELASTOMER SOCKET FOR HIGH-SPEED QFP ICs
The SG-QFE-7011 is a high-performance QFP socket for 0.4-mm pitch, 128-pin QFPs. The socket is designed for a
1.6-mm × 14-mm × 14-mm package size with a 16-mm × 16-mm lead tip to tip. It operates at bandwidths up to 10 GHz with less than 1 dB of insertion loss and has a typical 20 mΩ per I/O contact resistance. The socket connects all pins with 10-GHz bandwidth on all connections. The small-footprint socket is mounted with supplied hardware on the target PCB. No soldering is required. The small footprint enables inductors, resistors, and decoupling capacitors to be placed close to the device for impedance tuning.
The SG-QFE-7011’s swivel lid has a compression screw that enables ICs to be quickly changed out. The socket features a floating compression plate to force down the QFP leads on to elastomer. A hard-stop feature is built into the compression mechanism.
The sockets are constructed with high-performance, low-inductance gold-plated embedded wire on elastomer as interconnect material between a device and a PCB. They feature a –35°C-to-100°C temperature range, a 0.15-nH pin self inductance, a 0.025-nH mutual inductance, a 0.01-pF capacitance to ground, and a 2-A per pin current capacity.
The SG-QFE-7011 costs $474.
Are you experiencing designer’s block? Having a hard time starting a new project? You aren’t alone. After more than 11 months of designing and programming (which invariably involved numerous successes and failures), many engineers are simply spent. But don’t worry. Just like every other year, new projects are just around the corner. Sooner or later you’ll regain your energy and find yourself back in action. Plus, we’re here to give you a boost. The December issue (Circuit Cellar 269) is packed with projects that are sure to inspire your next flurry of innovation.
Turn to page 16 to learn how Dan Karmann built the “EBikeMeter” Atmel ATmega328-P-based bicycle computer. He details the hardware and firmware, as well as the assembly process. The monitoring/logging system can acquire and display data such as Speed/Distance, Power, and Recent Log Files.
Another interesting project is Joe Pfeiffer’s bell ringer system (p. 26). Although the design is intended for generating sound effects in a theater, you can build a similar system for any number of other uses.
You probably don’t have to be coerced into getting excited about a home control project. Most engineers love them. Check out Scott Weber’s garage door control system (p. 34), which features a MikroElektronika RFid Reader. He built it around a Microchip Technology PIC18F2221.
Once considered a hobby part, Arduino is now implemented in countless innovative ways by professional engineers like Ed Nisley. Read Ed’s article before you start your next Arduino-related project (p. 44). He covers the essential, but often overlooked, topic of the Arduino’s built-in power supply.
Need to extract a signal in a noisy environment? Consider a lock-in amplifier. On page 50, Robert Lacoste describes synchronous detection, which is a useful way to extract a signal.
This month, Bob Japenga continues his series, “Concurrency in Embedded Systems” (p. 58). He covers “the mechanisms to create concurrently in your software through processes and threads.”
On page 64, George Novacek presents the second article in his series, “Product Reliability.” He explains the importance of failure rate data and how to use the information.
Jeff Bachiochi wraps up the issue with a article about using heat to power up electronic devices (p. 68). Fire and a Peltier device can save the day when you need to charge a cell phone!
Set aside time to carefully study the prize-winning projects from the Reneas RL78 Green Energy Challenge (p. 30). Among the noteworthy designs are an electrostatic cleaning robot and a solar energy-harvesting system.
Lastly, I want to take the opportunity to thank Steve Ciarcia for bringing the electrical engineering community 25 years of innovative projects, essential content, and industry insight. Since 1988, he’s devoted himself to the pursuit of EE innovation and publishing excellence, and we’re all better off for it. I encourage you to read Steve’s final “Priority Interrupt” editorial on page 80. I’m sure you’ll agree that there’s no better way to begin the next 25 years of innovation than by taking a moment to understand and celebrate our past. Thanks, Steve.
Andrew Spitz is a Copenhagen, Denmark-based sound designer, interaction designer, programmer, and blogger studying toward a Master’s interaction design at the Copenhagen Institute of Interaction Design (CIID). Among his various innovative projects is the Arduino-based Skube music player, which is an innovative design that enables users to find and share music.
On his blog SoundPlusDesign.com, Spitz writes:
It is a fully working prototype through the combination of using Arduino, Max/MSP and an XBee wireless network. We access the Last.fm API to populate the Skube with tracks and scrobble, and using their algorithms to find similar music when in Discover mode.
The following is an abridged version of an interview that appears in the December 2012 issue of audioXpress magazine, a sister publication of Circuit Cellar magazine..
SHANNON BECKER: Tell us a little about your background and where you live.
Andrew Spitz: I’m half French, half South African. I grew up in France, but my parents are South African so when I was 17, I moved to South Africa. Last year, I decided to go back to school, and I’m now based in Copenhagen, Denmark where I’m earning a master’s degree at the Copenhagen Institute of Interaction Design (CID).
SHANNON: How did you become interested in sound design? Tell us about some of your initial projects.
Andrew: From the age of 16, I was a skydiving cameraman and I was obsessed with filming. So when it was time to do my undergraduate work, I decided to study film. I went to film school thinking that I would be doing cinematography, but I’m color blind and it turned out to be a bigger problem than I had hoped. At the same time, we had a lecturer in sound design named Jahn Beukes who was incredibly inspiring, and I discovered a passion for sound that has stayed with me.
Shannon: What do your interaction design studies at CIID entail? What do you plan to do with the additional education?
Andrew: CIID is focused on a user-centered approach to design, which involves finding intuitive solutions for products, software, and services using mostly technology as our medium. What this means in reality is that we spend a lot of time playing, hacking, prototyping, and basically building interactive things and experiences of some sort.
I’ve really committed to the shift from sound design to interaction design and it’s now my main focus. That said, I feel like I look at design from the lens of a sound designer as this is my background and what has formed me. Many designers around me are very visual, and I feel like my background gives me not only a different approach to the work but also enables me to see opportunities using sound as the catalyst for interactive experiences. Lots of my recent projects have been set in the intersection among technology, sound, and people.
SHANNON: You have worked as a sound effects recordist and editor, location recordist and sound designer for commercials, feature films, and documentaries. Tell us about some of these experiences?
ANDREW: I love all aspects of sound for different reasons. Because I do a lot of things and don’t focus on one, I end up having more of a general set of skills than going deep with one—this fits my personality very well. By doing different jobs within sound, I was able to have lots of different experiences, which I loved! nLocation recording enabled me to see really interesting things—from blowing up armored vehicles with rocket-propelled grenades (RPGs) to interviewing famous artists and presidents. And, documentaries enabled me to travel to amazing places such as Rwanda, Liberia, Mexico, and Nigeria. As a sound effects recordist on Jock of the Bushvelt, a 3-D animation, I recorded animals such as lions, baboons, and leopards in the South African bush. With Bakgat 2, I spent my time recording and editing rugby sounds to create a sound effects library. This time in my life has been a huge highlight, but I couldn’t see myself doing this forever. I love technology and design, which is why I made the move...
SHANNON: Where did the idea for Skube originate?
Andrew: Skube came out of the Tangible User Interface (TUI) class at CIID where we were tasked to rethink audio in the home context. So understanding how and where people share music was the jumping-off point for creating Skube.
We realized that as we move more toward a digital and online music listening experience, current portable music players are not adapted for this environment. Sharing mSkube Videousic in communal spaces is neither convenient nor easy, especially when we all have such different taste in music.
The result of our exploration was Skube. It is a music player that enables you to discover and share music and facilitates the decision process of picking tracks when in a communal setting.
audioXpress is an Elektor International Media publication.
Why shell out hundreds or thousands of dollars on various home control systems (HCS) when you have the skills and resources to build your own? You can design and implement sophisticated Internet-enabled systems with free tools and some careful planning.
John Breitenbach did just that. He used a microcontroller, free software, and a cloud-based data platform to construct a remote monitoring system for his home’s water heater. The innovative design can email or text status messages and emergency alerts to a smartphone. You can build a similar system to monitor any number of appliances, rooms, or buildings.
An abridged version of Breitenbach’s article, “Internet-Enabled Home Control” (Circuit Cellar 264, July 2012), appears below. (A link to the entire article and an access password are noted at the end of this post.) Breitenbach writes:
Moving from the Northeast to North Carolina, my wife and I were surprised to find that most homes don’t have basements. In the north, the frost line is 36˝–48 ˝ below the surface. To prevent frost heave, foundations must be dug at least that deep. So, digging down an extra few feet to create a basement makes sense. Because the frost line is only 15 ˝ in the Raleigh area, builders rarely excavate the additional 8’ to create basements.
The lack of basements means builders must find unique locations for a home’s mechanical systems including the furnace, AC unit, and water heater. I was shocked to find that my home’s water heater is located in the attic, right above one of the bedrooms (see Photo 1).
During my high school summers I worked for my uncle’s plumbing business (“Breitenbach Plumbing—We’re the Best, Don’t Call the Rest”) and saw firsthand the damage water can do to a home. Water heaters can cause some dramatic end-of-life plumbing failures, dumping 40 or more gallons of water at once followed by the steady flow of the supply line.
Having cleaned up the mess of a failed water heater in my own basement up north, I haven’t had a good night’s sleep since I discovered the water heater in my North Carolina attic. For peace of mind, especially when traveling, I instrumented my attic so I could be notified immediately if water started to leak. My goal was to use a microcontroller so I could receive push notifications via e-mails or text messages. In addition to emergency messages, status messages sent on a regular basis reassure me the system is running. I also wanted to use a web browser to check the current status at any time.
MCU & SENSOR
The attic monitor is based on Renesas Electronics’s YRDKRX62N demonstration kit, which features the RX62N 32-bit microcontroller (see Photo 2). Renesas has given away thousands of these boards to promote the RX, and the boards are also widely available through distributors. The YRDK board has a rich feature set including a graphics display, push buttons, and an SD-card slot, plus Ethernet, USB, and serial ports. An Analog Devices ADT7420 digital I2C temperature sensor also enables you to keep an eye on the attic temperature. I plan to use this for a future addition to the project that compares this temperature to the outside air temperature to control an attic fan.
Commercial water-detection sensors are typically made from two exposed conductive surfaces in close proximity to each other on a nonconductive surface. Think of a single-sided PCB with no solder mask and tinned traces (see Photo 3).
These sensors rely on the water conductivity to close the circuit between the two conductors. I chose a sensor based on this type of design for its low cost. But, once I received the sensors, I realized I could have saved myself a few bucks by making my own sensor from a couple of wires or a piece of proto-board.
When standing water on the sensor shorts the two contacts, the resistance across the sensor drops to between 400 kΩ and 600 kΩ. The sensor is used as the bottom resistor in a voltage divider with a 1-MΩ resistor up top. The output of the divider is routed to the 12-bit analog inputs on the RX62N microcontroller. Figure 1 shows the sensor interface circuit. When the voltage read by the analog-to-digital converter (ADC) drops below 2 V, it’s time to start bailing. Two sensors are connected: one in the catch pan under the water heater, and a second one just outside the catch pan to detect failures in the small expansion tank.
One of my project goals was to push notifications to my cell phone because Murphy’s Law says water heaters are likely to fail while you’re away for the weekend. Because I wanted to keep the project costs low, I used my home’s broadband connection as the gateway for the attic monitor. The Renesas RX62N microcontroller includes a 100-Mbps Ethernet controller, so I simply plugged in the cable to connect the board to my home network. The open-source µIP stack supplied by Renesas with the YRDK provides the protocol engine needed to talk to the Internet.
There were a couple of complications with using my home network as the attic monitor’s gateway to the world. It is behind a firewall built into my router and, for security reasons, I don’t want to open up ports to the outside world.
My Internet service provider (ISP) occasionally changes the Internet protocol (IP) address associated with my cable modem. So I would never know what address to point my web browser. I needed a solution that would address both of these problems. Enter Exosite, a company that provides solutions for cloud-based, machine-to-machine (M2M) communications.
TALKING TO THE CLOUD
Exosite provides a number of software components and services that enable M2M communications via the cloud. This is a different philosophy from supervisory control and data acquisition (SCADA) systems I’ve used in the past. The control systems I’ve worked on over the years typically involve a local host polling the hundreds or thousands of connected sensors and actuators that make up a commercial SCADA system. These systems are generally designed to be monitored locally at a single location. In the case of the attic monitor, my goal was to access a limited number of data points from anywhere, and have the system notify me rather than having to continuously poll. Ideally, I’d only hear from the device when there was a problem.
Exosite is the perfect solution: the company publishes a set of simple application programming interfaces (APIs) using standard web protocols that enable smart devices to push data to their servers in the cloud in real time. Once the data is in the cloud, events, alerts, and scripts can be created to do different things with the data—in my case, to send me an e-mail and SMS text alert if there is anything wrong with my water heater. Connected devices can share data with each other or pull data from public data sources, such as public weather stations. Exosite has an industrial-strength platform for large-scale commercial applications. It provides free access to it for the open-source community. I can create a free account that enables me to connect one or two devices to the Exosite platform.
Embedded devices using Exosite are responsible for pushing data to the server and pulling data from it. Devices use simple HTTP requests to accomplish this. This works great in my home setup because the attic monitor can work through my firewall, even when my Internet provider occasionally changes the IP address of my cable modem. Figure 2 shows the network diagram.
VIRTUAL USER INTERFACE
Web-based dashboards hosted on Exosite’s servers can be built and configured to show real-time and historical data from connected devices. Controls, such as switches, can be added to the dashboards to push data back down to the device, enabling remote control of embedded devices. Because the user interface is “in the cloud,” there is no need to store all the user interface (UI) widgets and data in the embedded device, which greatly reduces the storage requirements. Photo 4 shows the dashboard for the attic monitor.
Events and alerts can be added to the dashboard. These are logical evaluations Exosite’s server performs on the incoming data. Events can be triggered based on simple comparisons (e.g., a data value is too high or too low) or complex combinations of a comparison plus a duration (e.g., a data value remains too high for a period of time). Setting up a leak event for one of the sensors is shown in Photo 5.
In this case, the event is triggered when the reported ADC voltage is less than 2 V. An event can also be triggered if Exosite doesn’t receive an update from the device for a set period of time. This last feature can be used as a watchdog to ensure the device is still working.
When an event is triggered, an alert can optionally be sent via e-mail. This is the final link that enables an embedded device in my attic to contact me anywhere, anytime, to alert me to a problem. Though I have a smartphone that enables me to access my e-mail account, I can also route the alarm message to my wife’s simpler phone through her cellular provider’s e-mail-to-text-message gateway. Most cellular providers offer this service, which works by sending an e-mail to a special address containing the cell phone number. On the Verizon network, the e-mail address is <yourcellularnumber>@vtext.com. Other providers have similar gateways.
The attic monitor periodically sends heartbeat messages to Exosite to let me know it’s still working. It also sends the status of the water sensors and the current temperature in the attic. I can log in to Exosite at any time to see my attic’s real-time status. I have also configured events and alarms that will notify me if a leak is detected or if the temperature gets too hot…
The complete article includes details such about the Internet engine, reading the cloud, tips for updating the design, and more. You can read the entire article by typing netenabledcontrol to open the password-protected PDF.
German engineer Jens Altenburg’s solar-powered hidden observing vehicle system (SOPHECLES) is an innovative gas-detecting mobile robot. When the Texas Instruments MSP430-based mobile robot detects noxious gas, it transmits a notification alert to a PC, Altenburg explains in his article, “SOPHOCLES: A Solar-Powered MSP430 Robot.” The MCU controls an on-board CMOS camera and can wirelessly transmit images to the “Robot Control Center” user interface.
The MSP430 microcontroller controls SOPHOCLES. Why did I need an MSP430? There are lots of other micros, some of which have more power than the MSP430, but the word “power” shows you the right way. SOPHOCLES is the first robot (with the exception of space robots like Sojourner and Lunakhod) that I know of that’s powered by a single lithium battery and a solar cell for long missions.
How is this possible? The magic mantra is, “Save power, save power, save power.” In this case, the most important feature of the MSP430 is its low power consumption. It needs less than 1 mA in Operating mode and even less in Sleep mode because the main function of the robot is sleeping (my main function, too). From time to time the robot wakes up, checks the sensor, takes pictures of its surroundings, and then falls back to sleep. Nice job, not only for robots, I think.
The power for the active time comes from the solar cell. High-efficiency cells provide electric energy for a minimum of approximately two minutes of active time per hour. Good lighting conditions (e.g., direct sunlight or a light beam from a lamp) activate the robot permanently. The robot needs only about 25 mA for actions such as driving its wheel, communicating via radio, or takes pictures with its built in camera. Isn’t that impossible? No! …
The robot has two power sources. One source is a 3-V lithium battery with a 600-mAh capacity. The battery supplies the CPU in Sleep mode, during which all other loads are turned off. The other source of power comes from a solar cell. The solar cell charges a special 2.2-F capacitor. A step-up converter changes the unregulated input voltage into 5-V main power. The LTC3401 changes the voltage with an efficiency of about 96% …
If the input voltage increases to about 3.5 V (at the capacitor), the robot will wake up, changing into Standby mode. Now the robot can work.
The approximate lifetime with a full-charged capacitor depends on its tasks. With maximum activity, the charging is used after one or two minutes and then the robot goes into Sleep mode. Under poor conditions (e.g., low light for a long time), the robot has an Emergency mode, during which the robot charges the capacitor from its lithium cell. Therefore, the robot has a chance to leave the bad area or contact the PC…
The control software runs on a normal PC, and all you need is a small radio box to get the signals from the robot.
Various buttons and throttles give you full control of the robot when power is available or sunlight hits the solar cells. In addition, it’s easy to make short slide shows from the pictures captured by the robot. Each session can be saved on a disk and played in the Robot Control Center…
The entire article appears in Circuit Cellar 147 2002. Type “solarrobot” to access the password-protected article.
Do you want to add a powerful wireless Android device to your own projects? Now you can, and doing so is easier than you think.
With their high-resolution touchscreens, ample computing power, WLAN support, and telephone functions, Android smartphones and tablets are ideal for use as control centers in your projects. But until now, it has been difficult to connect them to external circuitry. Elektor’s AndroPod interface board, which adds a serial TTL port and an RS-485 port to the picture, changes this situation.
In a free webinar on June 21, 2012, Bernhard Wörndl-Aichriedler (codesigner of the AndroPod Interface) will explain how easy it is to connect your own circuitry to an Android smartphone using the AndroPod interface. Click here to register.
Elektor Academy and element14 have teamed up to bring you a series of exclusive webinars covering blockbuster projects from recent editions of Elektor magazine. Participation in these webinars is completely free!
Webinar: AndroPod – Bridging Android and Your Electronics Projects
Date: Thursday June 21, 2012
Time: 16:00 CET
Presenter: Bernhard Wörndl-Aichriedler (Codesigner of the Andropod Interface)
CircuitCellar.com is an Elektor International Media publication.
Ralph Berres, a television technician in Germany, created an exemplary design space in his house for working on projects relating to his two main technical interests: amateur radio and metrology (the science of measurement). He even builds his own measurement equipment for his bench.
“I am a licensed radio amateur with the call sign DF6WU… My hobby is high-frequency and low-frequency metrology,” Berres wrote in his submission.
Amateur radio is popular among Circuit Cellar readers. Countless electrical engineers and technical DIYers I’ve met or worked with during the past few years are amateur radio operators. Some got involved in radio during childhood. Others obtained radio licenses more recently. For instance, Rebecca Yang of Tymkrs.com chronicled the process in late 2011. Check it out: http://youtu.be/9HfmyiHTWZI and http://tymkrs.tumblr.com/.
Do you want to share images of your workspace, hackspace, or “circuit cellar” with the world? Click here to email us your images and workspace info.
In the U.S., a common gift to give someone when he or she finishes school or completes a course of career training is Dr. Seuss’s book, Oh, the Place You’ll Go. I thought of the book’s title when I first read our May interview with engineer Lawrence Foltzer. After finishing electronics training in the U.S. Navy, Foltzer found himself working in such diverse locations as a destroyer in Mediterranean Sea, IBM’s Watson Research Center in Yorktown Heights, NY, and Optilink, DSC, Alcatel, and Turin Networks in Petaluma, CA. Simply put: his electronics training has taken him to many interesting places!
Foltzer’s interests include fiber optic communication, telecommunications, direct digital synthesis, and robot navigation. He wrote four articles for Circuit Cellar between June 1993 and March 2012.
Below is an abridged version of the interview now available in Circuit Cellar 262 (May 2012).
NAN: You spent 30 years working in the fiber optics communication industry. How did that come about? Have you always had an interest specifically in fiber optic technology?
LARRY: My career has taken me many interesting places, working with an amazing group of people, on the cusp of many technologies. I got my first electronics training in the Navy, both operating and maintaining the various anti-submarine warfare systems including the active sonar system; Gertrude, the underwater telephone; and two fire-control electromechanical computers for hedgehog and torpedo targeting. I spent two of my four years in the Navy in schools.
When I got out of the Navy in 1964, I managed to land a job with IBM. I’d applied for a job maintaining computers, but IBM sent me to the Thomas J. Watson Research Center in Yorktown Heights, NY. They gave me several tests on two different visits before hiring me. I was one of four out of forty who got a job. Mine was working in John B. Gunn’s group, preparing Gunn-oscillator samples and assisting the physicists in the group in performing both microwave and high-speed pulsed measurements.
One of my sample preparation duties was the application of AuGeNi ohmic contacts on GaAs samples. Ohmic contacts were essential to the proper operation of the Gunn effect, which is a bulk semiconductor phenomenon. Other labs at the research center were also working with GaAs for other devices: the LED, injection laser diode, and Hall-effect sensors to name a few. It turned out that the evaporated AuGeNi contact used on the Gunn devices was superior to the plated AuSnIn contact, so I soon found myself making 40,000 A per square centimeter pulsed-diode lasers. A year later I transferred to Gaithersburg, MD, to IBM-FSD where I was responsible for transferring laser diode technology to the group that made battlefield laser illuminators and optical radars. We used flexible light guides to bring the output from many lasers together to increase beam brightness.
As the Vietnam war came to an end, IBM closed down the Laser and Quantum Electronics (LQE) group I was in, but at the same time I received a job offer to join Comsat Labs, Clarksburg, MD, from an engineer for whom I had built Gunn devices for phased array studies. So back to the world of microwaves for a few years where I worked on the satellite qualification of tunnel (Asaki) diodes, Impatt diodes, step-recovery diodes, and GaAs FETs.
About a year after joining Comsat Labs, the former head of the now defunct IBM-LQE group, Bill Culver, called on me to help him prove to the army that a “single-fiber,” over-the-hill guided missile could replace the TOW missile and save soldier lives from the target tanks counterfire.
NAN: Tell us about some of your early projects and the types of technologies you used and worked on during that time.
LARRY: So, in 1973-ish, Bill Culver, Gordon Gould (Laser Inventor), and I formed Optelecom, Inc. In those days, when one spoke of fiber optics, one meant fiber bundles. Single fibers were seen as too unreliable, so hundreds of fibers were bundled together so that a loss of tens of fibers only caused a loss of a few percent of the injected light. Furthermore, bundles presented a large cross section to the primitive light sources of the day, which helped increase transmission distances.
Bill remembered seeing one of C. L. Stong’s Amateur Scientist columns in Scientific American about a beam balance based on a silica fiber suspension. In that column, Stong had shown that silica fibers could be made with tensile strengths 20 times that of steel. So a week later, Bill and I had constructed a fiber drawing apparatus in my basement and we drew the first few meters of fiber of the approximately 350 km of fiber we made in my home until we captured our first army contract and opened an office in Gaithersburg, MD.
Our first fibers were for mechanical-strength development. Optical losses measured hundreds of dBs/km in those days. But our plastic clad silica (PCS) fiber losses pretty much tracked those of Corning, Bell Labs, and ITT-EOPD (Electro-Optics Products Division). Pretty soon we were making 8 dB/km fibers up to 6 km in length. I left Optelecom when follow-on contracts with the army slowed; but by that time we had demonstrated missile payout of 4 km of signal carrying fiber at speeds of 600 ft/s, and slower speed runs from fixed-wing and Helo RPVs. The first video games were born!
At Optelecom I also worked with Gordon Gould on a CO2 laser-based secure communications system. A ground-based laser interrogated a Stark-effect based modulator and retro-reflector that returned a video signal to the ground station. I designed and developed all of that system’s electronics.
Government funding for our fiber payout work diminished, so I joined ITT-EOPD in 1976. In those days, if you needed a connector or a splice, or a pigtailed LED, laser or detector, you made it yourself; and I was good with my hands. So, in addition to running programs to develop fused fiber couplers, etc., I was also in charge of the group that built the emitters and detectors needed to support the transmission systems group.
NAN: You participated in Motorola’s IEEE-802 MAC subcommittee on token-passing access control methods. Tell us about that experience.
NAN: How long have you been designing MCU-based systems? Tell us about your first MCU-based design.
LARRY: I was in Motorola’s strategic marketing department (SMD) when the Apple 2 first came on the scene. Some of the folks in the SMD were the developers of the RadioShack color computer. Long story short, I quickly became a fan of the MC6809 CPU, and wrote some pretty fancy code for the day that rotated 3-D objects, and a more animated version of Space Invaders. I developed a menu-driven EPROM programmer that could program all of the EPROMs then available and then some. My company, Computer Accessories of AZ, advertised in Rainbow magazine until the PC savaged the market. I sold about 1,200 programmers and a few other products before closing up shop.
NAN: Circuit Cellar has published four of your articles about design projects. Your first article, “Long-Range Infrared Communications” was published in 1993 (Circuit Cellar 35). Which advances in IR technology have most impressed and excited you since then?
LARRY: Vertical cavity surface-emitting lasers (VCSEL). The Japanese were the first to realize their potential, but did not participate in their early development. Honeywell Optoelectronics was the first to offer 850-nm VCSELs commercially. I think I bought my first VCSELs from Hamilton Avnet in the late 1980s for $6 a pop. But 850 nm is excluded from Telecom (Bellcore), so companies like Cielo and Picolight went to work on long wavelength parts. I worked with Cielo on 1310-nm VCSEL array technology while at Turin Networks, and actually succeeded in adding VCSEL transmitter and array receiver optics to several optical line cards. It was my hope that VCSELs would find their way into the fiber to the home (FTTH) systems of the future, delivering 1 Gbps or more for 33% of what it costs today.
Circuit Cellar 262 (May 2012) is now on newsstands.
Circuit Cellar has published dozens of interesting articles about handy wireless applications over the years. And now we have another innovative project to report about. Circuit Cellar author Robert Bowen contacted us recently with a link to information about his iFarm-II controller data acquisition system.
The design features two main components. Bowen’s “iFarm-Remote” and the “iFarm-Base controller” work together to as an accurate remote wireless data acquisition system. The former has six digital inputs (for monitoring relay or switch contacts) and six digital outputs (for energizing a relay’s coil). The latter is a stand-alone wireless and internet ready controller. Its LCD screen displays sensor readings from the iFarm-Remote controller. When you connect the base to the Internet, you can monitor data reading via a browser. In addition, you can have the base email you notifications pertaining to the sensor input channels.
The iFarm-II Controller is a wireless data acquisition system used to remotely monitor temperature and humidity conditions in a remote location. The iFarm consists of two controllers, the iFarm-Remote and iFarm-Base controller. The iFarm-Remote is located in remote location with various sensors (supports sensors that output +/-10VDC ) connected. The iFarm-Remote also provides the user with 6-digital inputs and 6-digital outputs. The digital inputs may be used to detect switch closures while the digital outputs may be used to energize a relay coil. The iFarm-Base supports either a 2.4GHz or 900Mhz RF Module.
The iFarm-Base controller is responsible for sending commands to the iFarm-Remote controller to acquire the sensor and digital input status readings. These readings may be viewed locally on the iFarm-Base controllers LCD display or remotely via an Internet connection using your favorite web-browser. Alarm conditions can be set on the iFarm-Base controller. An active upper or lower limit condition will notify the user either through an e-mail or a text message sent directly to the user. Alternatively, the user may view and control the iFarm-Remote controller via web-browser. The iFarm-Base controllers web-server is designed to support viewing pages from a PC, Laptop, iPhone, iTouch, Blackberry or any mobile device/telephone which has a WiFi Internet connection.—Robert Bowen, http://wireless.xtreemhost.com/
Robert Bowen is a senior field service engineer for MTS Systems Corp., where he designs automated calibration equipment and develops testing methods for customers involved in the material and simulation testing fields. Circuit Cellar has published three of his articles since 2001:
The Embedded Systems Conference has always been a top venue for studying, discussing, and handling the embedded industry’s newest leading-edge technologies. This year in San Jose, CA, I walked the floor looking for the tech Circuit Cellar and Elektor members would love to get their hands on and implement in novel projects. Here I review some of the hundreds of interesting products and systems at Design West 2012.
Renesas launched the RL78 Design Challenge at Design West. The following novel RL78 applications were particularly intriguing.
- An RL78 L12 MCU powered by a lemon:
- An RL78 kit used for motor control:
- An RL78 demo for home control applications:
Circuit Cellar members have used TI products in countless applications. Below are two interesting TI Cortex-based designs
A Cortex-M3 digital guitar (you can see the Android connection):
Stellaris fans will be happy to see the Stellaris ARM Cortex -M4F in a small wireless application:
Due to the success of the recent NXP mbed Design Challenge, I stopped at the mbed station to see what exciting technologies our NXP friends were exhibiting. They didn’t disappoint. Check out the mbed-based slingshot developed for playing Angry Birds!
Below is a video of the project on the mbedmicro YouTube page:
I was pleased to see the Elektor AndroPod hard at work at the FTDI booth. The design enables users to easily control a robotic arm with Android smartphones and tablets.
As you can imagine, the possible applications are endless.
Here’s a sneak peek at the projects and topics slated for the April issue of Circuit Cellar: Linux software development tools, DIY cap-touch, gain-controlled amplifier; color classification reader; start designing with the Renesas RL78 microcontroller; an introduction to sigma-delta modulators; RFI bypassing, with a focus on parallel capacitors; mesh networking simplified with SNAP technology; and more.
Clemens Valens introduces the Renesas Electronics RL78:
Jeff Bachiochi takes a close look at Synapse Wireless SNAP technology:
Ed Nisley presents Part 2 of his article series “RFI Bypassing”:
The April issue will hit newsstands in late March.