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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

Propeller Multicore MCU Released as Open-Source Design

Parallax released its source code design files for the Propeller 1 (P8X32A) multicore microcontroller at the DEFCON 22 Conference in Las Vegas, where the chip was also featured on the conference’s electronic badge. Parallax managers said they anticipate the release will inspire developers. Hobbyists, engineers, and students can now view and modify the Propeller Verilog design files by loading them into low-cost field programmable gate array (FPGA) development boards. The design was released under the GNU General Public License v3.0.

Source: Parallax

Source: Parallax

With the chip’s source code now available, any developer can discover what they need to know about the design. The open release provides a way for developers who have requested more pins, memory, or other architectural improvements to make their own version to run on an FPGA. Universities who have requested access to the design files for their engineering programs will now have them.

The Propeller multicore microcontroller is used in developing technologies where multiple sensors, user interface systems, and output devices such as motors must be managed simultaneously. Some primary applications for Parallax’s chip include flight controllers in UAVs, 3-D printing, solar monitoring systems, environmental data collection, theatrical lighting and sound control, and medical devices.

For more information on Parallax’s open source release of the Propeller P8X32A, visit www.parallax.com.

 

High-Voltage LDO Regulator

To add to its growing family of voltage regulator solutions, Linear Technology recently announced the LT3061, a high-voltage, low-noise, low-dropout voltage linear regulator with active output discharge. The device can deliver up to 100 mA of continuous output current with a 250-mV dropout voltage at full load. The LT3061 features an NMOS pull-down that discharges the output when SHDN or IN is driven low. This rapid output discharge is useful for applications requiring power conditioning on both start-up and shutdown (e.g., high-end imaging sensors).

Source: Linear Technology

Source: Linear Technology

A single external capacitor provides programmable low noise reference performance and output soft-start functionality. The LT3061 has a quiescent current of 45 μA and provides fast transient response with a minimum 3.3-μF output capacitor. In shutdown, the quiescent current is less than 3 μA and the reference soft-start capacitor is reset.

Its main features include:

  • Wide 1.6 V to 45 V input voltage range.
  • Adjustable output voltages from 0.6 V to 19 V.
  • Ultralow noise operation of 30 µVRMS across a 10 Hz to 100 kHz bandwidth.
  • Low quiescent current of 45 µA (operating) and < 2 µA (in shutdown).

The LT3061 is available as an adjustable device with an output voltage range from the 600-mV reference up to 19 V. The chip is supplied in a thermally enhanced eight-lead 2 mm × 3 mm DFN and MSOP outline. For more information visit www.linear.com

 

 

 

System Engineer’s Space for Designing & Testing

Many complicated motion control and power electronics systems comprise thousands of parts and dozens of embedded systems. Thus, it makes sense that a systems engineer like New Jersey-based John Roselle would have more than one workspace for simultaneously planning, designing, and testing multiple systems.

(Source: John Roselle)

John Roselle’s space for designing circuits and electronic systems (Source: John Roselle)

Roselle recently submitted images of his space and provided some interesting feedback when we asked him about it.

My main work space for testing and debugging of circuits consists of nothing more than a kitchen table with two shelves attached to the wall.  Shown in the picture (see above) a 265-V digital motor drive for a fin control system for an under water application.  In a second room I have a computer design center.

I design and test mostly motor drives for motion control products for various applications, such as underwater vehicles, missile hatch door motor drives, and test equipment for testing the products I design.

Computer design center (Source: John Roselle)

A second room serves as “computer design center” (Source: John Roselle)

John’s third workspace is used mainly for testing and assembling. At times there might be two or three different projects going on at once, he added.

(Source: John Roselle)

The third space is used to test and assemble systems (Source: John Roselle)

Do you want to share images of your workspace, hackspace, or “circuit cellar”? Send us your images and info about your space.

How to Protect Electronic Systems

Engineers must protect their electronic systems. Thus, we frequently get requests for tips, tricks, and insight on the topic. For instance, a UK-based community member recently requested some insight into electronics protection and bullet proofing. We provided him with the content below. And now we want to pass it on to you as well.

Robert Lacoste shows the 3-D printer (a) he used to build an acrylonitrile butadiene styrene (ABS) shield (b).

Robert Lacoste shows the 3-D printer (a) he used to build an acrylonitrile butadiene styrene (ABS) shield (b).

Self-Reconfiguring Robotic Systems & M-Blocks

Self-reconfiguring robots are no longer science fiction. Researchers at MIT are rapidly innovating shape-shifting robotic systems. In the August 2014 issue of Circuit Cellar, MIT researcher Kyle Gilpin presents M-Blocks, which are 50-mm cubic modules capable of controlled self-reconfiguration.

The creation of autonomous machines capable of shape-shifting has been a long-running dream of scientists and engineers. Our enthusiasm for these self-reconfiguring robots is fueled by fantastic science fiction blockbusters, but it stems from the potential that self-reconfiguring robots have to revolutionize our interactions with the world around us.

Source: Kyle Gilpin

Source: Kyle Gilpin

Imagine the convenience of a universal toolkit that can produce even the most specialized tool on demand in a matter of minutes. Alternatively, consider a piece of furniture, or an entire room, that could change its configuration to suit the personal preferences of its occupant. Assembly lines could automatically adapt to new products, and construction scaffolding could build itself while workers sleep. At MIT’s Distributed Robotics Lab, we are working to make these dreams into reality through the development of the M-Blocks.

The M-Blocks are a set of 50-mm cubic modules capable of controlled self-reconfiguration. Each M-Block is an autonomous robot that can not only move independently, but can also magnetically bond with other M-Blocks to form larger reconfigurable systems. When part of a group, each module can climb over and around its neighbors. Our goal is that a set of M-Blocks, dispersed randomly across the ground, could locate one another and then independently move to coalesce into a macro-scale object, like a chair. The modules could then reconfigure themselves into a sphere and collectively roll to a new location. If, in the process, the collective encounters an obstacle (e.g., a set of stairs to be ascended), the sphere could morph into an amorphous collection in which the modules climb over one another to surmount the obstacle.  Once they have reached their final destination, the modules could reassemble into a different object, like a desk.

The M-Blocks move and reconfigure by pivoting about their edges using an inertial actuator. The energy for this actuation comes from a 20,000-RPM flywheel contained within each module. Once the motor speed has stabilized, a servomotor-driven, self-tightening band brake decelerates the flywheel to a complete stop in 15 ms. All of the momentum that had been accumulated in the flywheel is transferred to the frame of the M-Block. Consequently, the module rolls forward from one face to the next, or if the flywheel velocity is high enough, it rapidly shoots across the ground or even jumps several body lengths through the air. (Refer to www.youtube.com/watch?v=mOqjFa4RskA  to watch the cubes move.)

While the M-Blocks are capable of independent movement, their true potential is only realized when many modules operate as a group. Permanent magnets on the outside of each M-Block serve as un-gendered connectors. In particular, each of the 12 edges holds two cylindrical magnets that are captive, but free to rotate, in a semi-enclosing cage. These magnets are polarized through their radii, not through their long axes, so as they rotate, they can present either magnetic pole. The benefit of this arrangement is that as two modules are brought together, the magnets will automatically rotate to attract. Furthermore, as one and then two additional M-Blocks are added to form a 2 × 2 grid, the magnets will always rotate to realign and accommodate the additional modules.

The same cylindrical magnets that bond neighboring M-Blocks together form excellent pivot axes, about which the modules may roll over and around one another. We have shown that the modules can climb vertically over other modules, move horizontally while cantilevered from one side, traverse while suspended from above, and even jump over gaps. The permanent magnet connectors are completely passive, requiring no control and no planning. Because all of the active components of an M-Block are housed internally, the modules could be hermetically sealed, allowing them to operate in extreme environment where other robotic systems may fail.

While we have made significant progress, many exciting challenges remain. In the current generation of modules, there is only a single flywheel, and it is fixed to the module’s frame, so the modules can only move in one direction along a straight line. We are close to publishing a new design that enables the M-Blocks to move in three dimensions, makes the system more robust, and ensures that the modules’ movements are highly repeatable. We also hope to build new varieties of modules that contain cameras, grippers, and other specialized, task-specific tools. Finally, we are developing algorithms that will allow for the coordinated control of large ensembles of hundreds or thousands of modules. With this continued development, we are optimistic that the M-Blocks will be able to solve a variety of practical challenges that are, as of yet, largely untouched by robotics.

Kyle Gilpin

Kyle Gilpin

ABOUT THE AUTHOR

Kyle Gilpin, PhD, is a Postdoctoral Associate in the Distributed Robotics Lab at the Massachusetts Institute of Technology (MIT) where he is collaborating with Professor Daniela Rus and John Romanishin to develop the M-Blocks. Kyle works to improve communication and control in large distributed robotic systems. Before earning his PhD, Kyle spent two years working as a senior electrical engineer at a biomedical device start-up. In addition to working for MIT, he owns a contract design and consulting business, Crosscut Prototypes. His past projects include developing cellular and Wi-Fi devices, real-time image processing systems, reconfigurable sensor nodes, robots with compliant SMA actuators, integrated production test systems, and ultra-low-power sensors.

Circuit Cellar 289 (August 2014) is now available.