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Wireless rover meets 3d design and product development.

Technology and engineering teachers are always looking for learning activities that are challenging, fun, and inspire student interest, imagination, and motivation. Additionally, technology teachers recognize that learning activities should meet other dimensions too. These include providing a measure of success, meeting program goals and objectives, as well as making science, technology, engineering, and mathematics (STEM) connections to the overall program. Students who are enthusiastic about the technology learning activities and classes are more likely to share their enthusiasm with others and assist in building program enrollment.

Students are fascinated with smart phones and all kinds of "intelligent" technologies. Learning about 3D printing and using smart phones to communicate with a robotic rover can add a new dimension to the learning activities in the technology lab or classroom.

Today many would say that we are at the beginning of a new Industrial Revolution in the way that we design, manufacture, and make things. Then, could we ask, is this not the case ever since the Industrial Revolution began in the 1700s? During the Industrial Revolution in Great Britain and Europe, inventions such as the steam engine, textile production, the factory system, iron production, railroads, and many other developments were considered revolutionary. The new revolution is the digital revolution, and it is significantly changing the way that we communicate, design, and manufacture products that we may need or desire as consumers.

Today we see machine tools, controlled by computers, effortlessly machine complex components that are assembled by robotic systems quickly and accurately. A closer look reveals that these machines may be completing their processing in ways that were once thought of as "science fiction." Powerful lasers controlled by computers cut and weld materials with such precision that only the thickness of a human hair separates the process or parts. However, many of the products manufactured in the past and even today rely on some form of "chip or material removal" process, which is one of several manufacturing processes. These processes--casting molding, forming, machining, and joining--are typically used to manufacture individual parts and assemblies that end up as the products that consumers may use on a daily basis in work and recreation.

Products such as household appliances--washing machines, refrigerators, toasters--and items like toys, bicycles, scooters, cars, and trucks incorporate a variety of manufacturing methods in their creation. As we look to the horizon, we can see that another manufacturing method is making great progress in the way that we make and use things. This process is called additive processing or manufacturing. 3D printing is an additive production process. While 3D printing is not entirely new, what is new is a burgeoning industrial and consumer market that is changing the way that we look at 3D printing and its impact. Charles Hull is noted for creating the first functional 3D printer in 1984. Since that time, manufacturing and aerospace industries have saved billions of dollars by using 3D printing technologies for building parts. (Chowdhry, 2013)

Not too long ago it was common to read in popular magazines about making "replacement parts for broken products right on your workbench or desktop!" Today this has become more of a reality than we may realize. The price of 3D printers has fallen dramatically over the years. Today a good quality compact printer may be purchased for a technology and engineering lab for less than $500. The price today is very different from just a few years ago when 3D printers cost tens of thousands of dollars. Keep in mind, however, that consumer lines of 3D printers don't have the precision and capability for a variety of materials that are used for printing by industrial and production quality machines.

As we look at "3D printing, or additive manufacturing, [it] has come a long way from its roots in the production of simple plastic prototypes. Today, 3D printers can not only handle materials ranging from titanium to human cartilage but also produce fully functional components, including complex mechanisms, batteries, transistors, and LEDs" (Cohen, Sargent, Somers, 2014).

The Ford Motor Company and General Motors both use 3D printing technologies in the production of prototypes to save time and money. Ford uses 3D printing to design and produce a number of parts for its vehicle prototypes such as brake rotors, cylinder heads, control knobs, etc. General Motors used 3D technologies to produce prototype parts for its 2014 Chevrolet Malibu. Engineers used stereo lithography special software and laser sintering technologies to refine and improve parts for the Malibu (Chowdhry, 2013).

It is surprising where we may see 3D printed products. In the recent James Bond movie Skyfall, scale models of MI5's infamous Aston Martin DB5 were made for "explosive demolition" scenes. The film's producers had three scale models that were printed using 3D technology that could be easily filmed being "destroyed" without damaging the original DB5, yet were virtually indistinguishable from the real DB5! (Warman, 2012).

General Electric, a multinational company that manufactures consumer, business, and industrial products, has contracted with a Swedish company, Arcam, to produce 3D-printed parts for its jet engines. A pilot project is planned to produce 3D-printed gas turbine fuel nozzles. Traditional manufacturing methods required the production of twenty separate parts that had to be assembled to make a single nozzle. Alternatively, a 3D-printing technology was used to produce a single part. However, it was also realized that the 3D process is much slower but much more cost-effective where small quantities of parts are required as compared to traditional methods. Siemens also announced that it would be using 3D Selective Laser Melting (SLM) to manufacture small quantities of gas turbine components. SLM technology uses a metal powder that is heated and fused layer-by-layer to build a part. A high-powered laser fuses the metal particles together to form a solid part according to programmed instructions reflecting the part's design and features. (Overton, 2014)

3D printing technologies are finding their way into the medical and dental fields. Patients who need organ replacements may not need to wait for a donor. Using 3D printing technologies, doctors can "print" organs through regenerative medicine techniques using 3D printed artificial scaffolds in the shape of an organ. The scaffold is first printed and then coated with living cells where the cells can grow. In the past, the scaffolds were made by hand, which was a tedious and time-consuming process. Such innovative techniques provide lifesaving solutions to very real human problems. (Chowdhry, 2013)

Printing in space! NASA astronauts aboard the International Space Station (ISS) captured the imagination and enthusiasm of many avid followers here on earth with their 3D printer. The Space Station team printed a number of articles using the world's first zero gravity 3D printer. The most famous print was a ratchet wrench--fully functional! It is interesting to note that the 3D model was designed by Noah Paul-Gin, an engineer at Made in Space, Inc. in northern California. The 3D file was "uplinked" (emailed) to the space station by the Made in Space team here on Earth and printed aboard the International Space Station Expedition 42. The ratchet wrench was returned to Earth for testing at NASA's Marshall Space Flight Center. The 3D printer trial was like many other mission experiments and provided a proof of concept for engineers. In the future, the results could pave the way for producing repair parts on-site in a space environment rather than transporting them from a NASA site on earth (NASATV, 2014).

There are many variants in the 3D printing technologies based on printing process, material, deposition rates, and size and accuracy. Several of the most common 3D printing technologies are selective laser sintering (SLS), stereo lithography (SLA), and fused deposition modeling (FDM). Today fused deposition modeling is becoming the most common low-cost 3D printing technology used in technology labs. Small, compact desktop 3D printers are available for less than $2,500, are very capable, and use low-cost materials. The production capabilities typically are less than 8" X 8" X 8" and may print one or two colors without changing the filament material. These low-cost 3D printers use a small diameter, 1.75 or 3.0mm filament made of ABS or PLA thermoplastic. The filament material is available in a variety of colors such as red, white, green, blue, black, yellow, and natural. Fluorescent colors are also available.

While the surprisingly low cost of these printers may be cause for some concern about the quality of the printer and capabilities as a technology learning tool, these concerns may quickly be dispelled. There are a number of low-cost 3D printers available that are durable, provide stable and repeatable results, and easily achieve instructional goals. It is important to recognize that the 3D printing process is slow, and in many cases student projects cannot be printed in one class period.

There are educational technology suppliers that offer 3D printing technologies and curriculum materials that provide structured instructional content and learning activities. Alternatively, a 3D printer or printers may be purchased, and the technology and engineering teacher can develop his or her own unique instructional materials. It should be understood that a successful 3D printed project begins with a good quality 3D model. The software that accompanies low-cost 3D printers varies substantially. Some include proprietary modeling and printing software to design and drive the printer, while others include only software to view and print a 3D model STL file. There are many "ready-toprint" 3D files available on the Internet. Students may use readyto-print files to experience the 3D printing process. However, to create original work, 3D modeling software is necessary to create a printable model. There is readily available browser-based software that can be downloaded from the Internet including Google SketchUp, 3DTin, Blender, and others. Commercial 3D modeling software applications include AutoCAD, Autodesk Inventor, Dassault Systemes SolidWorks, Rhinoceros 3D, and other proprietary applications.

UBIQUITOUS MICROCONTROLLERS

Today we see in nearly every consumer, business, and industrial product that has some form of "intelligence or smartness" a microcontroller or computer. Microcontrollers are used in our digital watches, calculators, and appliances such as coffee brewers, electric ranges, washing machines, and many other products that we use every day. Our automobiles make extensive use of microcontrollers for engine operation, management functions, and safety features, as well as entertainment and communication features found in many new automobiles. We also may consider these little microcontrollers as a basic building block or component that is part of the design and function of the projects that we may build in our technology labs where some form of control or interactivity is desirable.

While individual microcontrollers such as PIC (Peripheral Interface Controller), Atmel-AVR, or ARM MCUs (Microcontroller Units) are "miniature computers on a chip," they generally need minimum components for display, input and outputs, as well as power and interface connections to be useful. Thus, they require advanced knowledge and skills to understand the MCUs to incorporate and integrate into student projects. There are literally thousands of different types of microcontrollers with several major manufacturers such as Microchip, Atmel, Texas Instruments, Altera, and others. However, there are a number of alternatives to the component levels of the MCUs that are available to teachers and students, who will be able to use the MCUs' features and functions without the advanced engineer technical skills. Several popular controller platforms are Parallax's Basic Stamp series and NetMedia's BasicX microcontrollers as well as the Arduino Open Source prototyping platforms such as the Arduino Uno, Mega 2650, and Zero. Each of these platforms has pre-designed add-on and peripheral accessory modules to extend input, output, and control capabilities. These add-on modules or boards are called shields or daughter-boards and provide a means to easily connect motors, control capabilities, and enable communication devices and displays.

The microcontroller platforms and systems mentioned above are popular choices among technology, science, and engineering teachers. There are similar products that offer the same features and capabilities. Some even provide "snap-together" structural components that can be quickly assembled into robots, rovers, "walkers," and a host of other robotic and intelligent devices. Perhaps the most widely recognized "robotics construction kit" is the LEGO Mindstorms series, the latest being the EV3 system that combines the familiar construction system with advanced robotics capabilities. Additionally the VEX robotics platform offers a wide variety of structural components, motors, interface and control devices, as well as STEM-directed curriculum materials.

Arduino offers a variety of platform sizes and capabilities to meet some of the most demanding projects as well as the simplest such as a "flashing LED" project in getting started. The programming software, called the Integrated Development Environment (IDE), is common to all of the Arduino microcontroller boards, (Figure 1). It is available under the GPL "Open-Source" license. The IDE is a JAVA-based programming environment that uses a derivative similar to the C/C++ programming language.

An Arduino board is programmed with an IDE and a programming language that is a derivative of the C/C++ language. There are a number of ready-to-use software libraries available to meet nearly any programming task for Arduino-based projects that students may encounter. They offer the advantage of a quick and easy path to make creative and interesting projects.

The Arduino boards and shields are reasonably priced and readily available, and there is no charge for the "open-source" IDE software. The flexibility of Arduino and accessories, along with the "free" software, makes Arduino well worth considering as a "building block" for a wide variety of learning activities in the technology and engineering laboratory or classroom.

WIRELESS ROVER MEETS 3D PRINTING TECHNOLOGY

Robot rover activities offer many opportunities to bring together science, mathematics, and technology skills and knowledge. Additionally, they foster imagination in exploring adventures on Mars with the NASA rover shown in Figure 2. Problem solving and critical thinking are an integral part of the design and fabrication process along with language arts skills in writing, documenting, learning, and processing the progress of the activity. Mathematical skills are realized and applied in measuring and designing the 3D components. The assemblies of the designs with 3D modelling software are used before the actual components are printed. To be able to complete the project objectives, the science and technology concepts are fundamental to the understanding of programming procedures and strategies, where wireless technologies, power, and electrical principles quickly become significant, needed elements when accomplishing the desired activities.

The "3D Rover" illustrated in Figure 3, was designed using 3D design and modeling software. Sketches were made using pencil and paper or drawing software--imagination and creativity was the focus in developing several basic designs quickly and easily. Pencils are still useful tools in the technology lab! Subsequently, the sketches were translated into 2D and 3D CAD drawings that were refined. Stability, proportion, size, and dimensions are important considerations in designing a rovertype vehicle.

The rover design illustrated here uses a four-wheel drive system that consists of four small 6-volt DC gear motors and wheel assemblies. The gear motor wheel combination simplifies the design and fabrication process significantly. A pair of motor brackets are required to support the motor and wheel assemblies and provide means to attach a support for the electronic control components that make up the rover design. 3D modeling software was used to create a pair of symmetrical motor brackets to mount the gear motor and wheel assemblies. The 3D drawing file was then saved as a drawing file and subsequently saved as a stereolithographic (STL) file, which is a standard file format used by most 3D printers such as XYZPrinting's Da Vinci 1.0 3D printer used for this project.

The top of the rover design is fabricated from 3mm medium density PVC sheet material. The sheet PVC material is easy to cut and drill to size using simple hand tools or even using a CNC router that may be available in the technology lab, adding another technological process in the construction of the project. This part can also be printed by the 3D printer if the CNC router is not available. Holes were drilled to accommodate the Arduino, motor controller, and Bluetooth transceiver.

The decision to make the wireless connection to the rover design was based on simplicity and flexibility. Wireless Bluetooth communication technologies are widespread and used by many of the devices that we use daily in smart phones, entertainment appliances, and remote-control devices. There are several off-the-shelf Bluetooth devices that can be easily interfaced with the Arduino hardware. The arduino board has a built-in communication serial port (DO and D1) that may be connected directly to a serial Bluetooth transceiver such as shown in Figure 4. This enables the Arduino to "talk and listen" to another Arduino or other devices such as a computer or Android-based smart phone via a paired connection.

The Bluetooth transceiver module has a compatible serial port that is connected to the Arduino board. It should be noted that the Arduino board (UNO) has only one serial port, so the Bluetooth device must be disconnected when programing the Arduino. The Arduino program sketch "opens" a serial connection to receive data via the serial connection. By entering values for variables in our sketch using a smart phone app, we may easily turn the gear motors on or off as well as change the motor direction to move forward, backward, or turn. A touch screen "controller icon" displayed on a smart phone screen or desktop keyboard is used to communicate with the Arduino rover. The variable value is transmitted from the smart phone to the Bluetooth transceiver connected Arduino. Communication is established using a terminal a program such as SENA BTerm or Arduino RC for smart phones or HyperTerm with a Microsoft Windows PC.

SUMMARY

3D printing technologies are not new, but rather used by industry to create high-quality prototype components for automotive and industrial products. 3D printing has made substantial gains in industry and consumer markets because of the capability to create three-dimensional objects using a variety of materials. The most common materials are thermoplastics such as ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), epoxies, and metal powders such as aluminum, stainless steel, and titanium.

Today there are a number of 3D printing technologies that are low cost and within the budgets of middle and high school programs. Educational technology companies offer a variety of 3D printing technologies and parallel curriculum materials to enable technology and engineering teachers to easily add 3D learning activities to their programs.

Students may begin 3D printing activities by printing readymade or teacher-made files and progress toward creating their own 3D modeling files and printing. While thermoplastic 3D supplies are relatively inexpensive, the time required to print complex and large objects can be quite demanding and take more than one class period to print. It is important that the technology and engineering teacher realize the printing times and advise students accordingly. The rover design addressed here does not require advanced 3D design and modeling skills but rather offers a "beginning 3D" activity that maintains student interest and motivation.

The rover project broadens the learning experience by incorporating an Arduino microcontroller board along with a compatible Bluetooth transceiver and motor control module. Students develop awareness about how to control devices and appliances using Bluetooth and microcontroller technologies, which is reflective of the trends in smart phone use today and in the future.

REFERENCES

Chowdhry, A. (2013). What can 3D printing do? Here are 6 creative examples. Forbes/Tech, October, 8, 2013. Retrieved from http://forbes.com/sites/amitchowdhry/2013/10/08/ what-can-3d-printing-do-here-are-6-creative-examples/#7555805f61b0

Cohen, D., Sargeant, M., & Somers, K. (2014). 3-D printing takes shape. McKinsey Quarterly, January 2014. Retrieved from www.mckinsey.com/insights/manufacturing/3-d_printing_takes_shape

Warman, M. (2012). The name's printing, 3D printing. The Telegraph, Technology News, December 1,2012. Retrieved from www.telegraph/co.uk/technology/news/9712435/Thenames-Printing-3D-Printing.html

Overton, T. (2014). 3D metal printing turbine replacement parts could cut repair times by 90%. Power, February, 18, 2014. Retrieved from www.powermag.com/3d-metal-printing-turbine-replacement-parts-could-cut-repair-times-by-90/

NASA-TV. (2014, December 22). Space Station 3-D printer builds ratchet wrench to complete first phase of operations. Retrieved from www.nasa.gov/mission_pages/station/ research/news/3Dratchet_wrench

XYZprinting. (2015). XYZprinting and Barnes & Noble partner for educator week to bring 3D printers to stores nationwide. PR Newswire, October 16, 2015. Retrieved from http://finance. yahoo.com/news/xyzprinting-barnes-noble-partner-educator-130000916.html

Photo Credit: www.nasa.gov/multimedia/imagegallery/image_ feature_ 1265.html

Walter F. Deal, III, Ph.D., is an emeriti associate professor of STEM Education and Professional Studies at Old Dominion University, Norfolk, VA. Walt can be reached at wdeal@odu.edu.

Steve C. Hsiung, Ph.D., is professor of Engineering Technology at Old Dominion University, Norfolk, VA. Steve can be reached at shsiung@odu.edu.

3D printing goes mainstream! In the fall of 2015, bookseller Barnes & Noble announced the start of its "MiniMaker Faire." Barnes & Noble partnered with 3D printer maker XYZPrinting to display the Da Vinci 1.0 Junior 3D printer in its book stores to demonstrate many ways that 3D printing technology can be used in a collaborative learning environment in traditional classrooms and technology labs--particularly Science, Technology, Engineering, and Mathematics (STEM) programs, workshops, and everyday lives. (PR Newswire, 2015)

The "space ratchet" was the first tool made in space and essentially opened the door to potentially making needed repair parts in space. There are a dozen or so parts that are assembled into a functional ratchet wrench. A "ready-to-print" stereolithographic (STL) file designed by Made in Space Inc.'s engineer, Noah Paul-Gin, the ratchet wrench is available online at http://nasa3d.arc.nasa.gov/detail/ wrench-mis.

There are photographs and video files as well as the 3D files for printing the rover parts, and lists of components and Arduino boards are available online at www.ucdistanncetraining.org Select Download, then scroll down to Arduino.
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Title Annotation:RESOURCES IN TECHNOLOGY AND ENGINEERING
Author:Deal, Walter F., III; Hsiung, Steve C.
Publication:Technology and Engineering Teacher
Geographic Code:1USA
Date:Apr 1, 2016
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