Monthly Archives: September 2015

Technology Allows Writing in Air

Fujitsu has made what they claim to be a lightweight and compact wearable ring-type device offering handwriting functionality and capability of reading near-field communication tags. You can wear it on your index finger, and the ring has several sensors such as a gyroscope, an accelerometer and a magnetic sensor to help with text input, apart from wireless communication functionality and an NFC tag reader. The smart ring can identify the movement the user makes with his or her fingertips as they write in the air. To begin the air-writing process, the wearer has to press an operation button on the ring with the thumb. That makes the operation single-handed.

Fujitsu had already developed a glove-style of wearable device, last year. The current device, however, compresses the entire functionality into a ring-type instrument weighing less than 10-grams, suitable for wearing on a single finger. The tiny instrument has power-saving features and operates on a single button-cell battery.

The technology developed by Fujitsu successfully corrects letterform tracings. This feature improves the accuracy of character recognition, which the user traces in air with his finger. Its success rate is 95% and the capability includes Chinese characters and numbers. The user has only to tap a finger to get documentation and instructions for working on a device with the help of the built-n NFC tag reader.

The technology from the Fujitsu Laboratories is sophisticated enough to recognize automatically unwanted connections between the strokes of a letterform when the wearer is writing a longhand trace. It corrects the data accordingly, removing the unwanted connections and this improves the legibility and text-recognition rate tremendously.

With modern advances making smart devices more miniature, along with cloud environments and efficient communication technology, there is increasing interest in HMDs or Head Mounting Devices. These and other wearable devices are very useful for people engaged in maintenance and other tasks in buildings and factories. The operator can have both hands free because of the ICT or information and communication technology used in these wearable.

Therefore, operators are no longer required to hold devices in their hands to receive information in the field. Consequently, there are high expectations from the use of such wearable devices in fieldwork that allow operators to keep their hands free to use at all times.

According to Fujitsu, the smart ring-type wearable device is targeted for use in the working world rather than at homes. At present, the company is carrying out real-world tests on the device and they have a goal of practical implementation in 2015.

Not that Fujitsu is alone in developing such finger-sized wearable technology. Others are also present in this field. For example, Logbar Inc., operating from San Francisco and Tokyo, started a Kickstarter campaign in 2013 and was able to raise close to $900,000. They have developed their Ring, which is a wearable input device capable of enabling users to text and control home appliances. Additionally, it can help the wearer complete financial transactions as well. Unlike the Fujitsu device, which is suitable for workplaces, the Ring of Logbar is meant for consumer use at home – it is not yet available for purchase, though.

The humble cable assembly

In a project, the major focus is on active components, circuit design and software, in that order. However, what we tend to overlook is the humble cable and connectors that link all the components together. Nonetheless, along with the more glamorous components, the humble cable assemblies also define the success and reliability of your project.

Active devices and test equipment, being very tangible, always seem to command greater respect compared to the attention bestowed on the almost invisible cable and connector assemblies. This is true in both the prototyping and production cycles. However, this may prove unwise in the long run. Although wireless connectivity is catching up fast, in reality, hard-wired signal interconnects are still irreplaceable and indispensable parts of nearly all systems.

Once design engineers work on the gigahertz and higher ranges in their projects, it gets more challenging for them as cable assemblies play a more active role, both practically and figuratively. The importance of cables and connectors can be seen in RF/microwave-centric web sites and publications that devote more than one-third of their ads and content to the subject. In the high-frequency world, phase matching between two nominally identical assemblies is very often critical. This arena talks about second- and third-order parameters and the temperature coefficient of the cable’s specification gains importance. High-frequency designers treat cable assemblies with respect. For them, the assemblies are energy waveguides that are carefully engineered and modeled with precise dimensions, tested and fabricated.

Just as there are many cases of counterfeit components, mostly ICs and sometimes passive, Cabling and Installer have reported fake cable assemblies as well. In fact, this was one of their top 10 articles in 2014. Fake cable assemblies do not fully meet the operating specifications. They may somehow work, but fall short at higher data rates, or they cannot provide the specified power when used for PoE.

Not only the electrical performance, fake cable assemblies compromise safety as well. In most installations, a cable’s insulation is very important factor, as it must be fire-rated so as not to support combustion. This is usually not noticed unless a fire breaks out. Some fake assemblies even substitute the necessary copper wire with a brittle aluminum core and copper cladding.

It is very easy to make fake cables, stamping them with almost any rating required. Very few people test and verify the cable performance when faced with falling data rates and rising BERs. In most cases, we remain content with the Cat5/UL rating stamped on the cable, taking them as given. This is a concern that is bothering not the high-frequency instrument manufacturers alone, but also the audio industry, the aircraft industry and electrical distribution companies. Who can say the OFHC or Oxygen Free, High Conductivity audio cable is not actually a plain copper cable slapped with an OFHC label?

With the world now reaching out to 100GHz and beyond, cables are getting thinner, tinier, with hair-thin wires, and corresponding match-head sized connectors. At such high frequencies, every bend radius, routing guide stress, torque and abrasion from sharp edges becomes important and critical.

How do fiber optic cables carry light?

Nowadays, nearly everyone is talking about fiber-optic cables. These cables are now commonly used in telephone systems, cable TV systems and the Internet. One of the main advantages with optics cables is their huge bandwidth. That means fiber optics cables can carry far more signals than copper wires can. Usually made of optically pure glass, these cables are very thin – nearly as thin as human hair. Because of their high signal carrying capacity, optical fiber cables are also used for mechanical engineering inspection and in medical imaging. Optical fiber cables are made of long, thin strands of extremely pure glass. With a diameter close to that of human hair, several strands are bundled together, to form cables that are used to transmit light signals over long distances. When examined closely, each single fiber can be seen to consist of three parts.

The central core of the fiber is made of glass and this is where the light travels. The core is covered with a cladding, which effectively reflects light back into the core. The core is surrounded by a buffer coating, mainly for protecting the fiber from moisture ingress and physical damage. Optical cables contain hundreds or even thousands of such optical fibers arranged in bundles. On the outside, a jacket, also called the cable’s outer covering, protects the cable.
In general, there are two major types of optical fibers – single-mode and multi-mode. With a small core of about 9 microns in diameter, single-mode fibers can transmit infrared laser light having wavelengths of 1,300 to 1550 nanometers. On the other hand, multi-mode fibers have core diameters of about 62.5 microns, capable of transmitting infrared light of wavelengths from 850 to 1300 nanometers.

Other types of optical fibers can be made of plastic as well. These usually have a larger core of about 1 mm diameter, capable of transmitting visible red light of wavelength 650 nm, such as from LEDs.

Light always travels in straight lines. This is easily seen when a flashlight beam is shown down a straight long hallway. You can see the entire length of the hallway until the next bend, but beyond which nothing is visible. However, placing a mirror at the corner will allow you to see round the bend. This is possible because light from around the bend strikes the mirror and reflects down the hallway. If the hallway were to be very winding with multiple bends, lining the walls with mirrors will help. Light bounces from side-to-side and travels down the hallway making the entire path visible. This is exactly how an optical fiber works.

Light travels through the core of the fiber-optic cable, constantly bouncing off the cladding. This follows a well-known principle of optics known as total internal reflection. Very little light is lost in total internal reflection from the cladding, allowing light to travel long distances within the cable.

Although the core is made from optically pure glass, some impurities remain. These degrade the light signal as it travels down the core. The extent of signal degradation depends both on the impurities present in the glass used for the core and the wavelength of the light traveling through it.

Integrated Motors Simplify Motion Control

With machines getting more robust, smaller, less expensive and more reliable, engineers are facing the challenges of designing newer types of motion control. One way of addressing such motion control challenges, without being an expert in mechatronics is to use integrated motion control systems. Typically, these solutions combine the motor, the drive and the system components within a single unit. The system components include the intelligence or motion controller and input outputs all onboard. The use of an integrated solution allows the designer to focus more on the development of the machine and less on solving compatibility issues between various system components. The integrated motion system usually has all the components within a complete unit and sized for proper use. The decision to use an integrated motion system or an integrated motor usually depends on several factors. Major among them are requirements based on machine size, cost, reliability, modularity and distributed control.

With integrated motors, engineers can reduce the amount of space a machine needs. This is mainly the result of consolidation of components resulting in elimination of cabling. For example, an integrated motor may replace a drive and motor housed in separate enclosures, eliminating one of the enclosures. The panel space required reduces significantly for an integrated motor, while for a multi-axis system the real estate reduction can be substantial. However, an existing machine design must contain adequate space to house the integrated motor as this type of motor is larger than conventional motors.

Using integrated motors results in definite cost savings in contrast to using conventional components. One of the major saving in expenses comes from the absence of cabling that is no longer required with integrated motors. For example, the conventional drive may be located in a centralized cabinet with the motor a distance away on a long conveying machine. This arrangement needs considerable power cabling and feedback wiring between the motor and the drive. With the integrated motor, the drive being directly on the motor, much of the cabling is eliminated contributing to cost reduction.

With improvements in motor technology, the concern with reliability in integrated motors is outdated. The major point of concern earlier was heat buildup and dissipation. With reduced components making up the system, the reliability of integrated motors has improved because of the lower number of wire connections used. Better construction technology has improved the efficiency, decreasing the heat generated and the need for dissipation.

Industrial automation today requires modular machines. That essentially means smaller machines focusing on singular tasks combined to form a bigger system responsible for multiple functions. The smaller machines may operate independent of each other. This arrangement is beneficial because it allows engineers to change on modular section and transform the system into another customized machine. The modular concept is beneficial in shipping individual modules to the factory floor as the motor and drive of the integrated motor is placed directly in the machine.

As more and more industrial control is through PLC or Programmable Logic Controls, motor operations and synchronization through digital data signals is the norm. Since each integrated motor has its own controller, a distributed control system provides faster response and greater accuracies.

Connector Use Lowers Wiring Costs

Contrary to popular belief, hardwiring does not always minimize wire installation expenses. Hardwiring is a popular concept for those who regularly design and build industrial machines. People perceive it as one of the most common ways of saving installation costs when bringing power and signal to the machine. However, when the full range of wiring costs are factored in, these cost savings really seem just as a mirage does.

Installation costs typically involve time and materials, including the cost of the wire, cables, accessories and labor. However, if you look closely, there are less obvious hidden installation costs as well. These have individual considerations for labor and time-to-market.

For example, consider machines that need to be disassembled for shipping and then reassembled before startup. That means parts in the machine will have to be hardwired twice – once while testing and then again after shipping. Additionally, errors while wiring in the field are quite common, mostly when local electricians unfamiliar with the machine are handling the wiring. If you are lucky, such errors may only cause a delay in commissioning the machine. However, there can be worst-case scenarios, and faulty wiring may even damage the machine leading to expensive repairs. Along with such cost of errors, hardwired systems can be complex and expensive to test, so the cost of testing goes up as well.

As a rule of thumb, you can expect the hidden costs to go up exponentially with the number of connection points the machine has. Fortunately, use of connectors can help avoid all these hidden costs. Of course, connector components do add an upfront investment, but this money will be recouped and then some as connectors enable lower-cost machines, the machines can ship faster, they can be commissioned more quickly and offer ongoing savings.

Using connectors, engineers can build modular machines faster and with lower expenses. This approach to machine design allows engineers to pre-build common subsystems and components, and test and stock them for installation. Reusable modules lead to many machines being designed with common control panels, junction boxes, motor assemblies and populated cable tracks.

Connectors are a real advantage for shipping new and large machines, especially if these machines have to undergo some level of disassembly also. Disassembly usually involves unplugging cables from the bulkhead connectors of the panel, while connections and routing internal to the panel remain undisturbed. The process holds true for sensors and data cables, motor assemblies and junction boxes also.

At the destination, the machine requires all disconnected wires to be reconnected once again. A local electrician helped with a set of wiring schematics can simply perform this. Even if the electrician knows very little about the machine and the way it works, there is little chance of them making costly mistakes and adding to startup delays. Most modern connector systems are designed to disallow simple wiring errors. Where large, complex machines are to be installed and commissioned, connectors can reduce the time to a matter of days in place of the several weeks that hardwiring would have taken.