MCU-Based Projects and Practical Tasks

Circuit Cellar’s January issue presents several microprocessor-based projects that provide useful tools and, in some cases, entertainment for their designers.

Our contributors’ articles in the Embedded Applications issue cover a hand-held PIC IDE, a real-time trailer-monitoring system, and a prize-winning upgrade to a multi-zone audio setup.

Jaromir Sukuba describes designing and building the PP4, a PIC-to-PIC IDE system for programming and debugging a Microchip Technology PIC18. His solar-powered,

The PP4 hand-held PIC-to-PIC programmer

The PP4 hand-held PIC-to-PIC programmer

portable computing device is built around a Digilent chipKIT Max32 development platform.

“While other popular solutions can overshadow this device with better UI and OS, none of them can work with 40 mW of power input and have fully in-house developed OS. They also lack PP4’s fun factor,” Sukuba says. “A friend of mine calls the device a ‘camel computer,’ meaning you can program your favorite PIC while riding a camel through endless deserts.”

Not interested in traveling (much less programming) atop a camel? Perhaps you prefer to cover long distances towing a comfortable RV? Dean Boman built his real-time trailer monitoring system after he experienced several RV trailer tire blowouts. “In every case, there were very subtle changes in the trailer handling in the minutes prior to the blowouts, but the changes were subtle enough to go unnoticed,” he says.

Boman’s system notices. Using accelerometers, sensors, and a custom-designed PCB with a Microchip Technology PIC18F2620 microcontroller, it continuously monitors each trailer tire’s vibration and axle temperature, displays that information, and sounds an alarm if a tire’s vibration is excessive.  The driver can then pull over before a dangerous or trailer-damaging blowout.

But perhaps you’d rather not travel at all, just stay at home and listen to a little music? This issue includes Part 1 of Dave Erickson’s two-part series about upgrading his multi-zone home audio system with an STMicroelectronics STM32F100 microprocessor, an LCD, and real PC boards. His MCU-controlled, eight-zone analog sound system won second-place in a 2011 STMicroelectronics design contest.

In addition to these special projects, the January issue includes our columnists exploring a variety of  EE topics and technologies.

Jeff Bachiochi considers RC and DC servomotors and outlines a control mechanism for a DC motor that emulates a DC servomotor’s function and strength. George Novacek explores system safety assessment, which offers a standard method to identify and mitigate hazards in a designed product.

Ed Nisley discusses a switch design that gives an Arduino Pro Mini board control over its own power supply. He describes “a simple MOSFET-based power switch that turns on with a push button and turns off under program control: the Arduino can shut itself off and reduce the battery drain to nearly zero.”

“This should be useful in other applications that require automatic shutoff, even if they’re not running from battery power,” Nisley adds.

Ayse K. Coskun discusses how 3-D chip stacking technology can improve energy efficiency. “3-D stacked systems can act as energy-efficiency boosters by putting together multiple chips (e.g., processors, DRAMs, other sensory layers, etc.) into a single chip,” she says. “Furthermore, they provide high-speed, high-bandwidth communication among the different layers.”

“I believe 3-D technology will be especially promising in the mobile domain,” she adds, “where the data access and processing requirements increase continuously, but the power constraints cannot be pushed much because of the physical and cost-related constraints.”

Member Profile: Walter O. Krawec

Walter O. Krawec

Walter O. Krawec

LOCATION:
Upstate New York

OCCUPATION:
Research Assistant and PhD Student, Stevens Institute of Technology

MEMBER STATUS:
Walter has been reading Circuit Cellar since he got his first issue in 1999. Free copies were available at the Trinity College Fire Fighting Robot Contest, which was his first experience with robotics. Circuit Cellar was the first magazine for which he wrote an article (“An HC11 File Manager,” two-part series, issues 129 and 130, 2001).

TECH INTERESTS:
Robotics, among other things. He is particularly interested in developmental and evolutionary robotics (where the robot’s strategies, controllers, and so forth are evolved instead of programmed in directly).

RECENT TECH ACQUISITION:
Walter is enjoying his Raspberry Pi. “What a remarkable product! I think it’s great that I can take my AI software, which I’ve been writing on a PC, copy it to the Raspberry Pi, compile it with GCC, then off it goes with little or no modification!”

CURRENT PROJECTS:
Walter is designing a new programming language and interpreter (for Windows/Mac/Linux, including the Raspberry Pi) that uses a simulated quantum computer to drive a robot. “What better way to learn the basics of quantum computing than by building a robot around one?” The first version of this language is available on his website (walterkrawec.org). He has plans to release an improved version.

THOUGHTS ON EMBEDDED TECH:
Walter said he is amazed with the power of the latest embedded technology, for example the Raspberry Pi. “For less than $40 you have a perfect controller for a robot that can handle incredibly complex programs. Slap on one of those USB battery packs and you have a fully mobile robot,” he said. He used a Pololu Maestro to interface the motors and analog sensors. “It all works and it does everything I need.” However, he added, “If you want to build any of this yourself by hand it can be much harder, especially since most of the cool stuff is surface mount, making it difficult to get started.”

Client Profile: Digi International, Inc

Contact: Elizabeth Presson
elizabeth.presson@digi.com

Featured Product: The XBee product family (www.digi.com/xbee) is a series of modular products that make adding wireless technology easy and cost-effective. Whether you need a ZigBee module or a fast multipoint solution, 2.4 GHz or long-range 900 MHz—there’s an XBee to meet your specific requirements.

XBee Cloud Kit

Digi International XBee Cloud Kit

Product information: Digi now offers the XBee Wi-Fi Cloud Kit (www.digi.com/xbeewificloudkit) for those who want to try the XBee Wi-Fi (XB2B-WFUT-001) with seamless cloud connectivity. The Cloud Kit brings the Internet of Things (IoT) to the popular XBee platform. Built around Digi’s new XBee Wi-Fi
module, which fully integrates into the Device Cloud by Etherios, the kit is a simple way for anyone with an interest in M2M and the IoT to build a hardware prototype and integrate it into an Internet-based application. This kit is suitable for electronics engineers, software designers, educators, and innovators.

Exclusive Offer: The XBee Wi-Fi Cloud Kit includes an XBee Wi-Fi module; a development board with a variety of sensors and actuators; loose electronic prototyping parts to make circuits of your own; a free subscription to Device Cloud; fully customizable widgets to monitor and control connected devices; an open-source application that enables two-way communication and control with the development board over the Internet; and cables, accessories, and everything needed to connect to the web. The Cloud Kit costs $149.

Compact Wi-Fi Transceiver

Lemos

The LEMOS-LMX-WiFi wireless transceiver

The LEMOS-LMX-WiFi is a compact wireless transceiver that can operate on IEEE 802.11 networks. It is supported by a 32-bit microcontroller running a scalable TCP/IP stack. The transceiver is well suited for wireless embedded applications involving digital remote control, digital and analog remote monitoring, asset tracking, security systems, point of sale terminals, sensor monitoring, machine-to-machine (M2M) communication, environmental monitoring and control.

The 40.64-mm × 73.66-mm transceiver is available in two models: integrated PCB antenna or external antenna. Its features include software-selectable analog and digital I/O pins, a 2-Mbps maximum data rate, and a unique IEEE MAC address.

The LEMOS-LMX-WiFi can be powered by any 3.3-V to – 6-VDC source that can deliver 200 mA of current. The transceiver can interface to external devices that communicate via USART, I2C, and SPI. It also supports infrastructure and ad hoc networks.

Contact Lemos International for pricing.

Lemos International, Inc.
www.lemosint.com

I/O Raspberry Pi Expansion Card

The RIO is an I/O expansion card intended for use with the Raspberry Pi SBC. The card stacks on top of a Raspberry Pi to create a powerful embedded control and navigation computer in a small 20-mm × 65-mm × 85-mm footprint. The RIO is well suited for applications requiring real-world interfacing, such as robotics, industrial and home automation, and data acquisition and control.

RoboteqThe RIO adds 13 inputs that can be configured as digital inputs, 0-to-5-V analog inputs with 12-bit resolution, or pulse inputs capable of pulse width, duty cycle, or frequency capture. Eight digital outputs are provided to drive loads up to 1 A each at up to 24 V.
The RIO includes a 32-bit ARM Cortex M4 microcontroller that processes and buffers the I/O and creates a seamless communication with the Raspberry Pi. The RIO processor can be user-programmed with a simple BASIC-like programming language, enabling it to perform logic, conditioning, and other I/O processing in real time. On the Linux side, RIO comes with drivers and a function library to quickly configure and access the I/O and to exchange data with the Raspberry Pi.

The RIO features several communication interfaces, including an RS-232 serial port to connect to standard serial devices, a TTL serial port to connect to Arduino and other microcontrollers that aren’t equipped with a RS-232 transceiver, and a CAN bus interface.
The RIO is available in two versions. The RIO-BASIC costs $85 and the RIO-AHRS costs $175.

Roboteq, Inc.
www.roboteq.com