Flexible I/O Expansion for Rugged Applications

WynSystemsThe SBC35-CC405 series of multi-core embedded PCs includes on-board USB, gigabit Ethernet, and serial ports. These industrial computers are designed for rugged embedded applications requiring extended temperature operation and long-term availability.

The SBC35-CC405 series features the latest generation Intel Atom E3800 family of processors in an industry-standard 3.5” single-board computer (SBC) format COM Express carrier. A Type 6 COM Express module supporting a quad-, dual-, or single-core processor is used to integrate the computer. For networking and communications, the SBC35-CC405 includes two Intel I210 gigabit Ethernet controllers with IEEE 1588 timestamping and 10-/100-/1,000-Mbps multispeed operation. Four Type-A connectors support three USB 2.0 channels and one high-speed USB 3.0 channel. Two serial ports support RS-232/-422/-485 interface levels with clock options up to 20 Mbps in the RS-422/-485 mode and up to 1 Mbps in the RS-232 mode.

The SBC35-CC405 series also includes two MiniPCIe connectors and one IO60 connector to enable additional I/O expansion. Both MiniPCIe connectors support half-length and full-length cards with screw-down mounting for improved shock and vibration durability. One MiniPCIe connector also supports bootable mSATA solid-state disks while the other connector includes USB. The IO60 connector provides access to the I2C, SPI, PWM, and UART signals enabling a simple interface to sensors, data acquisition, and other low-speed I/O devices.

The SBC35-CC405 runs over a 10-to-50-VDC input power range and operates at temperatures from –40°C to 85°C. Enclosures, power supplies, and configuration services are also available.

Linux, Windows, and other x86 OSes can be booted from the CFast, mSATA, SATA, or USB interfaces, providing flexible data storage options. WinSystems provides drivers for Linux and Windows 7/8 as well as preconfigured embedded OSes.
The single-core SBC35-CC405 costs $499.

Winsystems, Inc.
www.winsystems.com

A Workspace for “Engineering Magic”

Brandsma_workspace2

Photo 1—Brandsma describes his workspace as his “little corner where the engineering magic happens.”

Sjoerd Brandsma, an R&D manager at CycloMedia, enjoys designing with cameras, GPS receivers, and transceivers. His creates his projects in a small workspace in Kerkwijk, The Netherlands (see Photo 1). He also designs in his garage, where he uses a mill and a lathe for some small and medium metal work (see Photo 2).

Brandsma_lathe_mill

Photo 2—Brandsma uses this Weiler lathe for metal work.

The Weiler lathe has served me and the previous owners for many years, but is still healthy and precise. The black and red mill does an acceptable job and is still on my list to be converted to a computer numerical control (CNC) machine.

Brandsma described some of his projects.

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Photo 3—Some of Brandsma’s projects include an mbed-based camera project (left), a camera with an 8-bit parallel databus interface (center), and an MP3 player that uses a decoder chip that is connected to an mbed module (right).

I built a COMedia C328 UART camera with a 100° lens placed on a 360° servomotor (see Photo 3, left).  Both are connected to an mbed module. When the system starts, the camera takes a full-circle picture every 90°. The four images are stored on an SD card and can be stitched into a panoramic image. I built this project for the NXP mbed design challenge 2010 but never finished the project because the initial idea involved doing some stitching on the mbed module itself. This seemed to be a bit too complicated due to memory limitations.

I built this project built around a 16-MB framebuffer for the Aptina MT9D131 camera (see Photo 3, center). This camera has an 8-bit parallel databus interface that operates on 6 to 80 MHz. This is way too fast for most microcontrollers (e.g., Arduino, Atmel AVR, Microchip Technology PIC, etc.). With this framebuffer, it’s possible to capture still images and store/process the image data at a later point.

This project involves an MP3 player that uses a VLSI VS1053 decoder chip that is connected to an mbed module (see Photo 3, right). The great thing about the mbed platform is that there’s plenty of library code available. This is also the case for the VS1053. With that, it’s a piece of cake to build your own MP3 player. The green button is a Skip button. But beware! If you press that button it will play a song you don’t like and you cannot skip that song.

He continued by describing his test equipment.

Brandma_test_equipment

Photo 4—Brandsma’s test equipment collection includes a Tektronix TDS220 oscilloscope (top), a Total Phase Beagle protocol analyzer (second from top), a Seeed Technology Open Workbench Logic Sniffer (second from bottom), and a Cypress Semiconductor CY7C68013A USB microcontroller (bottom).

Most of the time, I’ll use my good old Tektronix TDS220 oscilloscope. It still works fine for the basic stuff I’m doing (see Photo 4, top). The Total Phase Beagle I2C/SPI protocol analyzer Beagle/SPI is a great tool to monitor and analyze I2C/SPI traffic (see Photo 4, second from top).

The red PCB is a Seeed Technology 16-channel Open Workbench Logic Sniffer (see Photo 4, second from bottom). This is actually a really cool low-budget open-source USB logic analyzer that’s quite handy once in a while when I need to analyze some data bus issues.

The board on the bottom is a Cypress CY7C68013A USB microcontroller high-speed USB peripheral controller that can be used as an eight-channel logic analyzer or as any other high-speed data-capture device (see Photo 4, bottom). It’s still on my “to-do” list to connect it to the Aptina MT9D131 camera and do some video streaming.

Brandsma believes that “books tell a lot about a person.” Photo 5 shows some books he uses when designing and or programming his projects.

Brandsma_books

Photo 5—A few of Brandsma’s “go-to” books are shown.

The technical difficulty of the books differs a lot. Electronica echt niet moeilijk (Electronics Made Easy) is an entry-level book that helped me understand the basics of electronics. On the other hand, the books about operating systems and the C++ programming language are certainly of a different level.

An article about Brandsma’s Sun Chaser GPS Reference Station is scheduled to appear in Circuit Cellar’s June issue.

Remote Control and Monitoring of Household Devices

Raul Alvarez, a freelance electronic engineer from Bolivia, has long been interested in wireless device-to-device communication.

“So when the idea of the Internet of Things (IoT) came around, it was like rediscovering the Internet,” he says.

I’m guessing that his dual fascinations with wireless and the IoT inspired his Home Energy Gateway project, which won second place in the 2012 DesignSpark chipKIT challenge administered by Circuit Cellar.

“The system enables users to remotely monitor their home’s power consumption and control household devices (e.g., fans, lights, coffee machines, etc.),” Alvarez says. “The main system consists of an embedded gateway/web server that, aside from its ability to communicate over the Internet, is also capable of local communications over a home area wireless network.”

Alvarez catered to his interests by creating his own wireless communication protocol for the system.

“As a learning exercise, I specifically developed the communication protocol I used in the home area wireless network from scratch,” he says. “I used low-cost RF transceivers to implement the protocol. It is simple and provides just the core functionality necessary for the application.”

Figure1: The Home Energy Gateway includes a Hope Microelectronics RFM12B transceiver, a Digilent chipKIT Max32 board, and a Microchip Technology ENC28J60 Ethernet controller chip.

Figure 1: The Home Energy Gateway includes a Hope Microelectronics RFM12B transceiver, a Digilent chipKIT Max32 board, and a Microchip Technology ENC28J60 Ethernet controller chip.

Alvarez writes about his project in the February issue of Circuit Cellar. His article concentrates on the project’s TCI/IP communications aspects and explains how they interface.

Here is his article’s overview of how the system functions and its primary hardware components:

Figure 1 shows the system’s block diagram and functional configuration. The smart meter collects the entire house’s power consumption information and sends that data every time it is requested by the gateway. In turn, the smart plugs receive commands from the gateway to turn on/off the household devices attached to them. This happens every time the user turns on/off the controls in the web control panel.

Photo 1: These are the three smart node hardware prototypes: upper left,  smart plug;  upper right, a second smart plug in a breadboard; and at bottom,  the smart meter.

Photo 1: These are the three smart node hardware prototypes: upper left, smart plug; upper right, a second smart plug in a breadboard; and at bottom, the smart meter.

I used the simple wireless protocol (SWP) I developed for this project for all of the home area wireless network’s wireless communications. I used low-cost Hope Microelectronics 433-/868-/915-MHz RFM12B transceivers to implement the smart nodes. (see Photo 1)
The wireless network is configured to work in a star topology. The gateway assumes the role of a central coordinator or master node and the smart devices act as end devices or slave nodes that react to requests sent by the master node.

The gateway/server is implemented in hardware around a Digilent chipKIT Max32 board (see Photo 2). It uses an RFM12B transceiver to connect to the home area wireless network and a Microchip Technology ENC28J60 chip module to connect to the LAN using Ethernet.

As the name implies, the gateway makes it possible to access the home area wireless network over the LAN or even remotely over the Internet. So, the smart devices are easily accessible from a PC, tablet, or smartphone using just a web browser. To achieve this, the gateway implements the SWP for wireless communications and simultaneously uses Microchip Technology’s TCP/IP Stack to work as a web server.

Photo 2: The Home Energy Gateway’s hardware includes a Digilent chipKIT Max32 board and a custom shield board.

Photo 2: The Home Energy Gateway’s hardware includes a Digilent chipKIT Max32 board and a custom shield board.

Thus, the Home Energy Gateway generates and serves the control panel web page over HTTP (this page contains the individual controls to turn on/off each smart plug and at the same time shows the power consumption in the house in real-time). It also uses the wireless network to pass control data from the user to the smart plugs and to read power consumption data from the smart meter.

The hardware module includes three main submodules: The chipKIT Max 32 board, the RFM12B wireless transceiver, and the ENC28J60 Ethernet module. The smart meter hardware module has an RFM12B transceiver for wireless communications and uses an 8-bit Microchip Technology PIC16F628A microcontroller as a main processor. The smart plug hardware module shows the smart plugs’ main hardware components and has the same microcontroller and radio transceiver as the smart meter. But the smart plugs also have a Sharp Microelectronics S212S01F solid-state relay to turn on/off the household devices.

On the software side, the gateway firmware is written in C for the Microchip Technology C32 Compiler. The smart meter’s PIC16F628A code is written in C for the Hi-TECH C compiler. The smart plug software is very similar.

Alvarez says DIY home-automation enthusiasts will find his prototype inexpensive and capable. He would like to add several features to the system, including the ability to e-mail notifications and reports to users.

For more details, check out the February issue now available for download by members or single-issue purchase.

Six-Channel RS-422 Line Driver/Receiver

ic-HausThe iC-HF provides six RS-422 line drivers for 3-to-5.5-V encoder applications. The device contains reverse polarity protection for a safe sensor-side supply of up to 60 mA.

The iC-HF is pin configurable. A safe external signal sequence at two complementary line driver outputs activates the Encoder Link state. In the Encoder Link state, nine pins are connected from the sensor side to the field side. With this low-impedance bypassing, internal analog sensor signals and digital communication signals (e.g., BiSS, SPI, I²C, etc.) can be accessed at the line driver output pins.

With the integrated Encoder Link function, the line drivers can be deactivated and A/D signals can be directly accessed through the line driver output pins. Conventional sensors can be calibrated or programmed through the usual RS-422 outputs via the Encoder Link function. Extra contacts, pins, control lines, or signals are not needed. For differential RS-422 line driver operation, six differential complementary drivers are implemented.

Each push-pull driver stage can drive up to 65 mA maximum at 5 V and operate at up to a 10-MHz output frequency with RS-422 termination. The driver stages are current limited, short-circuit proof, and over-temperature protected. The current limitation also reduces electromagnetic compatibility (EMC).

The device provides under-voltage detection and on-chip temperature monitoring to switch the driver stages to high impedance on demand. A sensor error signal is combined with the iC-HF error states. When a fault occurs, the open-drain error output NERR is activated. All inputs are CMOS- and TTL-compatible and ESD protected.

The iC-HF’s operating temperatures range from –40°C to 125°C. The device is available in a 5-mm × 5-mm 32-pin QFN package. The design-in process is supported by ready-to-operate demonstration boards including the Encoder Link signal sequence generator.

The iC-HF costs $3.65 in 1,000-unit quantities.

iC-Haus GmbH
www.ichaus.com

Turn Your Android Device into an Application Tool

A few years ago, the Android Open Accessory initiative was announced with the aim of making it easier for hardware manufacturers to create accessories that work with every Android device. Future Technology Devices International (FTDI) joined the initiative and last year introduced the FTD311D multi-interface Android host IC. The goal was to enable engineers and designers to make effective use of tablets and smartphones with the Android OS, according to Circuit Cellar columnist Jeff Bachiochi.

The FTD311D “provides an instant bridge from an Android USB port(B) to peripheral hardware over general purpose input-out (GPIO), UART, PWM, I2C Master, SPI Slave, or SPI Master interfaces,” Bachiochi says.

In the magazine’s December issue Bachiochi takes a comprehensive look at the USB Android host IC and how it works. By the end of his article, readers will have learned quite a bit about how to use FTDI’s apps and the FT311D chip to turn an Android device into their own I/0 tool.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Here is how Bachiochi describes the FT311D and its advantages:

The FT311D is a full-speed USB host targeted at providing access to peripheral hardware from a USB port on an Android device. While an Android device can be a USB host, many are mobile devices with limited power. For now, these On-The-Go (OTG) ports will be USB devices only (i.e., they can only connect to a USB host as a USB device).

Since the USB host is responsible for supplying power to a USB peripheral device, it would be bad design practice to enable a USB peripheral to drain an Android mobile device’s energy. Consequently, the FT311D takes on the task of USB host, eliminating any draw on the Android device’s battery.

All Android devices from V3.1 (Honeycomb) support the Android Open Accessory Mode (AOAM). The AOAM is the complete reverse of the conventional USB interconnect. This game-changing approach to attaching peripherals enables three key advantages. First, there is no need to develop special drivers for the hardware; second, it is unnecessary to root devices to alter permissions for loading drivers; and third, the peripheral provides the power to use the port, which ensures the mobile device battery is not quickly drained by the external hardware being attached.

Since the FT311D handles the entire USB host protocol, USB-specific firmware programming isn’t required. As the host, the FT311D must inquire whether the connected device supports the AOAM. If so, it will operate as an Open Accessory Mode device with one USB BULK IN endpoint and one USB BULK OUT endpoint (as well as the control endpoint.) This interface will be a full-speed (12-Mbps) USB enabling data transfer in and out.

The AOAM USB host has a set of string descriptors the Android OS is capable of reading. These strings are (user) associated with an Android OS application. The Android then uses these strings to automatically start the application when the hardware is connected. The FT311D is configured for one of its multiple interfaces via configuration inputs at power-up. Each configuration will supply the Android device with a unique set of string descriptors, therefore enabling different applications to run, depending on its setup.

The FT311D’s configuration determines whether each application will have access to several user interface APIs that are specific to each configuration.

The article goes on to examine the various interfaces in detail and to describe a number of demo projects, including a multimeter.

Many of Bachiochi's projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Many of Bachiochi’s projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Multimeters are great tools. They have portability that enables them to be brought to wherever a measurement must be made. An Android device has this same ability. Since applications can be written for these devices, they make a great portable application tool. Until the AOAM’s release, there was no way for these devices to be connected to any external circuitry and used as an effective tool.

I think FTDI has bridged this gap nicely. It provided a great interface chip that can be added to any circuit that will enable an Android device to serve as an effective user I/O device. I’ve used the chip to quickly interface with some technology to discover its potential or just test its abilities. But I’m sure you are already thinking about the other potential uses for this connection.

Bachiochi is curious to hear from readers about their own ideas.

If you think the AOAM has future potential, but you want to know what’s involved with writing Android applications for a specific purpose, send me an e-mail and I’ll add this to my list of future projects!

You can e-mail Bachiochi at jeff.bachiochi@imaginethatnow.com or post your comment here.