Monthly Archives: December 2016

Can Electrocution Really Kill You?

Although cartoons tend to show a person being fried due to electrocution as the body flashes like fireworks with the bones visible to everyone, in reality, things do not work that way. Electricity does not actually fry you – unless you are struck by a thunderbolt. However, only a frighteningly miniscule amount of electricity is enough to snuff out your life.

At the beginning, it is necessary to get some facts clear. Some major units used by electrical engineers are – volts, amperes, watts, and ohms. Volts describe the difference in potential across two points, while amperes describe the amount of current flowing between the two points. Watts is a measure of the power flow between two points, and is the product of volts and amperes related to the two points. Ohm measures the resistance of a substance to the flow of current through it.

Plumbing offers a suitable analogy. Volts can be equated to the water pressure between the two ends of a pipe. Current is the same as the flow rate, while resistance is similar to the inner diameter of the pipe. As you increase the volts or the pressure, current, or water flow increases, assuming the diameter or resistance of the pipe has remained the same.

Scientists have conducted experiments on healthy humans to find an answer to “How much electricity is needed to kill a human?” The surprise answer is, only seven milli-amperes, for three seconds. Heart is an electrical pump and electricity reaching the heart interrupts its rhythm. The human heart goes arrhythmic and stops working when a current of seven milli-amperes passes through it continuously for three seconds. After that, the other parts of the body begin to shut down as well. Skin-penetrating Tasers do not kill, as the electric pulses they generate are of much shorter duration than that from three seconds.

However, our bodies have their own defenses against electric shock and that is why millions of people do not drop dead every minute with ultra-tiny shocks from the different electrical and electronic gadgets they always use. The major defense comes from the skin – it has a resistance of about 5,000 to 15,000 ohms. The clothes people wear add to the resistance of their skin. To break through such a formidable resistance, the static shock necessary just only to sting your skin is about 20,000 Volts. However, a person may not die from high-voltage electric shock if the electricity did not pass through the heart. If it traveled along the outside of their body, they would live, but likely with a scorched skin. This happens mostly when the skin is wet.

A lightning bolt is a different game altogether. One bolt of lightning can hit with over a billion volts. The resistance air offers to electricity is about 10,000 volts per centimeter. Therefore, for electricity simply to move current through 10 cm of air, the voltage required is 100,000 volts, and this is between the cloud generating the electricity and the earth below our feet. As high-voltage electricity or lightning takes the path of the least resistance when passing to the earth, it passes through the outer surface of the body, scorching the skin.

Use the Raspberry Pi for the Internet of Things

Barriers are coming down between operational technologies. Barriers such as were existing between industrial hardware and software for monitoring and controlling machines and the ERP systems and other information technology people typically use when operating and supporting their business. Manufacturers are having an exciting time as new opportunities are emerging every day for improving the productivity. Along with the rise in the challenges, there are innovations in creating new sources of customer value.

Data is not a new thing for manufacturers. In fact, there was enough data with manufacturers long before the Internet of Things and Big Data came into existence. Although manufacturers have been collecting and analyzing machine data for ages, they can now replace their legacy equipment and systems. With the explosion of the Internet of Things, the flow of data on the customers’ side is also ramping up. Networked products are tightening the connection between customers and manufacturers, with service capabilities expanding and creating entirely new revenue models.

With every organization wanting to participate in the Internet of Things, and IT professionals wanting to know how to add IoT skills to their resume, it is time to look at the different options for learning about IoT. Although there are many ways to gather this knowledge, nothing really can beat the hands-on experience.

The tiny single board computer, the Raspberry Pi or RBPi is one of the key learning platforms for IoT. Not only because this involves very low cost, but also because it offers a complete Linux server in its tiny platform. When you use the RBPi for learning about IoT, you will find that the most difficult thing to face is the picking the right project to make a start.
On the Web, you can find several thousand projects based on the RBPi. They involve the ambitious types, silly types, while some are really great for learning about Linux, RBPi, and the intricacies of the IoT.

When starting out with IoT projects and the RBPi, it is prudent to keep to a boundary – use some common sensors and or controller types. Custom-built hardware is fine for geeks, but for those who are just starting out with IoT, going wild with hardware builds can lead you astray.

While selecting a project, choose one that has something interesting going on for the control software. While it would be foolish to start with an epic development project, just to make a meaningful learning experience, simply calling pre-existing scripts and applications is also likely to cause a loss of interest.

Choose a fun project to start with. Of course, you will be training for the IoT. Nevertheless, training in the form of drudgery is no fun. Therefore, select a project that will want to make you move forward and continue your journey with the education.

You can buy individual sensors from the market and hook them up to your RBPi. However, as a beginner, you might be well off buying a kit for a specific use such as a single wire temperature sensor or a humidity sensor. Later, when more confident, you could move on to Hardware Attached on Top or HATs for the RBPi.

Pi-Top: Convert your Raspberry Pi into a Laptop

Although we call the Raspberry Pi or RBPi as a single board computer and it is small enough to fit in your pocket, it is hardly useful as a computer when you are on the move. This is mainly because the SBC comes without a keyboard, display, and mouse, intended to keep the costs down. However, if you are interested in turning your RBPi3 into a laptop, there is the Pi-Top.

You get everything necessary to turn your $35 single board computer into a laptop. For instance, you get a 13.3” HD LCD screen with an eDP interface and 1366×768 pixel resolution, which comes with an active 262K color matrix, anti-glare finish, and a 60 Hz refresh rate TFT LCD module. Additionally, you get a keyboard that is fully programmable via USB and a trackpad with a PalmCheck feature that helps prevent unwanted mouse clicks.

Although the Pi-Top converts the RBPI into a general-purpose laptop, its actual strength lies in its being a tinkerer’s toolkit. Pi-Top gives you great power management with LED battery indicators. The power supply requires an input capable of 18 V at 3 A, while it offers two outputs, one of 5 V, 3.5 A, and the other at 3.3 V, 500 mA. One good feature is the 3.3 V output is persistent. That means this voltage is available even when you have powered off the Pi-Top. Battery capacity is substantial, giving a run-time of 10-12 hours. There is protection for all outputs from over-current, over-voltage, over-temperature, and short-circuit. The smart battery pack uses a charging profile recommended by JEITA.

The hub-board of the Pi-Top has a screen driver that converts the HDMI output from the RBPi to the eDP 1.2 interface required by the LCD screen. It allows connection of UART, I2C, and SPI to the RBPi for use with add-on boards. There is even a PS/2 interface. The screen consumes 3 W, but you can dim it with a PWM screen dim control to make it consume less power.

Pi-Top comes with a manual to walk you through the assembly process in steps, while identifying clearly the part necessary to use at each stage. The manual has a pictorial guide to help in assembling the laptop. That makes the job relatively simpler. Since all the tools you need are already included, piecing together the case, cables, and boards into a working laptop is an unforgettable experience. However, you do need to be careful when tightening the smallish 2.5 mm nuts that hold the boards in place, as there are various electronic components on the boards.

Once assembled, the Pi-Top is an impressive sight, with its fluorescent green finish. The external case is injection-molded plastic and is sturdy enough to be travel-worthy. When powered on, you may be surprised at not seeing the familiar Linux-based Raspbian desktop on the screen. That is because the PI-Top re-skins the Raspbian desktop as the pi-topOS. Basically, they have added a launcher and configured the desktop to add a menu button at the bottom left corner – familiar to long-time Windows users with the Start menu.

Create Steam without Boiling Water

According to the primary text books of physics, pure water boils to produce steam at 100°C when the pressure equals 1 atmosphere or 760 mm of mercury, provided the heat supplied equals 640 Kcal for every Kilogram of water. That means, to produce steam, you need to boil water, so it changes its phase from liquid to gas. However, scientists are proving that it is possible to produce steam from water without boiling it – simply by supplying the latent heat necessary to change the phase.

Boiling is not necessary for producing steam if the vessel containing water is lined with a black material capable of absorbing a range of visible and infrared wavelengths of light. This material can create heat from sunlight and pass it on to the water, creating steam without the water going through the boiling stage.

According to a report in the Science Advances, scientists have created such a new, extremely black material. The material is a deep black color as it reflects very little visible light. The base material is pocked with tiny channels or Nano pores, over which there is a layer of gold nanoparticles each only a few billionths of a meter wide. This arrangement can absorb light from the visible spectrum and from some parts of the infrared spectrum, reaching 99% efficiency.

As the structure of the material is highly porous, it floats on water surface and soaks up the sunrays falling on it. As light falls on a gold nanoparticle within one of the Nano pores, photons in the applicable range of wavelength stir up electrons on the gold surface. The electrons oscillate back and forth, and the oscillating electrons are known as plasmons. The plasmons produce intense localized heating, vaporizing the water nearby.

To excite a plasmon, the wavelength of light has to match the size of the nanoparticle it hits. Therefore, to use as much of the sun’s spectrum as possible, scientists have created gold nanoparticles in the pores of a variety of sizes. That allows the material to absorb a large range of the wavelengths of light.

Jia Zhu, material scientist at the Nanjing University of China, is pioneering the research group. According to Jia, scientists have been successful in producing steam with plasmonic material earlier as well. However, the new material is different as it improves the efficiency of the entire process, and converts more than 90% of the light energy falling on it to steam.

According to mechanical engineer Nicholas Fang of MIT, not a part of the research, the team has actually produced an intriguing solution. Although scientists have achieved higher efficiencies with other material such as carbon nanotubes, the new material, though not as efficient, will be cheaper to manufacture.

Steam is a very useful form of energy and generating steam efficiently can help many industries. These include producing freshwater from saline water, also known as desalination, running steam engines and sterilization. In the industry, steam is used also for humidification, moisturization, cleaning, atomization, motive, propulsion, drive, and heating. There are several steam-using equipment as well.

Piq: This Ski-sensor Measures Details of your Skiing

Most skiers want feedback about their skiing, for improving their technique. The ski sensor from Rossignol offers one that not only does what skiers want in unprecedented detail, but also light and tiny enough to be unobtrusive. For instance, you get details about edge-to-edge transition time, in-air rotation, g-force, airtime and more. The sensor is slick enough and low profile, so you may not even notice that you have it on you.

This multi-sport ski sensor, Piq, measures just 44 x 38 x 5.4 mm. In the three-piece setup, the largest is the AA-battery sized charging unit. When not in use, you can simply plug this into the USB port of your computer and leave it for charging. It has a steel clamp to allow the Piq sensor to snap under it when you are resting. This gives the Piq sensor a quick recharge during say, lunchtime. In real use, the Piq sensor stays in a small pocket on the ankle strap that you strap around your ankle. You must be careful when you wrap and strap the ankle strap to prevent the Piq sensor from flying out during some of the most aggressive sessions.

Once you have had it on securely, you can forget about the Piq. Those who tried it on for multiple days, say the Piq never budged, even when the skier straight-lined it at over 100 kmph, jumped, skied corn snow, groomers, hard pack, and deep powder. In general, whether you slash, thrash, and even smash a few gates, this tiny, light, and secure Piq sensor will stay with you.

The Piq sensor has its own battery, powering it on for continuous tracking for about three hours, according to the manufacturer. In actual practice, the battery lasts longer than the manufacturer’s claim, before needing a recharge. This is indeed a big plus for the Piq, as it is very rare for the battery performance in a device to exceed the manufacturer’s claims.

While you are on the snow, the Piq sensor will track and record several statistics such as your speed, rotation time in the air, total airtime, G-force when you land, and the G-force when you take a turn. It will record your edge-to-edge transition time and the angulation of your ski in a turn, generally known as the carving degree. You can time your skiing time, as against standing or riding the chair, etc., your total run, and all your motions including the turns and jumps during the session. Piq will even count the turns per minute when you are skiing.

A free Android or iOS app companion allows the user to get access to the data the Piq sensor has acquired. No cable connection is necessary, as the smartphone connects to the sensor via Bluetooth 4.0. However, the app does not give you the data in real-time. Rather, it synchronizes your session when you trigger the specific function within the app.

An interactive, info-graphic style interface displays the data you pulled in and allows you to look at topline data for the session. You can then drill down to specifics about your turns and jumps.

Amputee Patients Feel Again Using Bionic Fingers

Although prosthetics do help amputees to get back some use of their missing limb, feeling is not among them. However, that may soon be changing now. Bionics prosthetics research from EPFL is promising enough to allow an amputee patient to perceive and distinguish between smooth and rough textures. An artificial finger connected surgically to nerves in the upper part of the patient’s arm does the trick. It is expected that this advance will expedite the development of the sense of touch in prosthetic limbs.

The EPFL research has also proven that the same prosthetic touch sensors meant for amputees can be easily tested on people who are able-bodied. For instance, non-amputee persons can feel roughness by stimulation of their nerves – without surgery.

Sylvestro Micera and his team at EPFL in Switzerland and SSSA in Italy have developed this technology in collaboration with Calogero Oddo and his team at SSSA – they have published the results in eLife. Their research is opening new windows on the development of bionic prostheses, and sensory perception is helping to improve the progress.

Dennis Aabo Sørensen, a hand amputee, is helping EPFL with its prosthetic research for some time. The team has implanted electrodes above the stump on his left forearm. The bionic finger connected to his stump allows him to feel sensations of texture at the tip of the index finger of his phantom hand. However, he still feels his missing hand as if he had a closed fist.

When EPFL connected a bionic hand to the electrodes in his left forearm, S⌀rensen could recognize both shape and softness. This time, the team wired the bionic finger to the electrodes meant for his fingertip. Rubbing the bionic finger against several pieces of plastic engraves with different patterns produced a sensation of texture at the tip of the index finger of his phantom hand. For 96 percent of the time, Sørensen was able to differentiate correctly between smooth and rough plastics using his bionic finger.

The group at SSSA in Italy tested the bionic finger on non-amputees while the subjects wore EEG caps. They noted the brain activity of the subjects while they were touching the plastic surfaces with their actual finger. They then compared these against the activity detected while they touched the same surfaces with the bionic fingertip. This was proof to the scientists that bionic fingers could activate the same parts of the brain, as did the real digits.

Therefore, the team is confident not only about leading to prosthetics that can feel, but also about offering the power of artificial touch to industrial, surgical and rescue robots as well.

The artificial fingertip was equipped with sensors that were wired to nerves in Sørensen’s arm. As the fingertip, assisted by a machine, moved over different pieces of plastic with smooth or rough patterns engraved on it, the sensors generated appropriate electrical signals. These signals were then translated into a series of electrical spikes to imitate the language of the nervous system. Once the spikes were delivered to the nerves, Sørensen was able to distinguish between rough and smooth surfaces with repeatable accuracy.

What Are The Cobots?

When inventors Joseph Eagleburger and George Devol were discussing about science fiction novels in 1954, they initiated the idea of industrial robots. It took them six years to give shape to their idea and Unimate entered a secure place in the robotic hall of fame, as the world’s first industrial robot. In 1961, Unimate began working on the assembly lines of the General Motors.

At first, people looked on with suspicion on the safety issues related to Unimate. At the time, the only reference people had for robots, was the laser-firing robot from “The Day the Earth Stood Still,” a thriller from the 1950s. Now, 50 years hence, industrial robots are far less scary.

Traditionally, robots were constructed to work under restriction inside robotic work cells with physical barriers for the safety of human workers. However, modern robots work completely outside any cage. On the factory floors today, working safely alongside their human counterparts, you will find unfettered working robots that are termed collaborative robots or cobots. Nevertheless, no robot is entirely devoid of health and safety features.

Unlike in the past, today’s industrial robots or cobots are designed specifically to work safely around humans. In fact, now robots work hand-in-hand with humans on the same assembly tasks and it has been independently certified that this is safe. The two-armed collaborative robot from ABB Robotics, YuMi, contributed largely to this certification.

To prevent accidents with human workers, cobots utilize sensors installed on them. The sensors monitor the location of humans around them on the factory floor and react to human contact. Therefore, even if a person does come too close to the machinery, it simply and automatically shuts down. Moreover, cobots work with strength, speed, and force limited to avoid causing serious injury to humans if there is any contact.

Most cobots are simple enough to require practically no skill in programming them. Anyone, who can operate a smartphone, can program them to operate. In contrast, complex robots of about a decade ago needed a host of highly skilled technicians to program and monitor them while in operation.

Among the industries that are being transformed by such collaborative machinery, the most to benefit is the automotive industry. As such, this sector has always been at the forefront of industrial robotics. Automotive manufacturers have been using robots and robotic equipment since the 1960s, but a lot has changed since then. The competitive nature of the industry forces manufacturing lines to be highly efficient, flexible and more productive than ever before.

Not that all this means any advancement in robotics is a threat to human jobs on the production line. For instance, builders use a concrete mixer to help the bricklayer and not to replace him. In the same way, collaborative robots only assist workers on the assembly line and do not actually replace them. According to some experts, production line workers will ultimately use collaborative robots as helpers in the same way as engineers use computers to further their own work and make their jobs easier.

Where Would You Apply Crowbar Protection?

Crowbar is an appliance typically used by construction workers. It is a heavy steel rod with one of its ends pointed and the other shaped like a spatula – both very useful for digging or breaking up construction rubble. Normally, one would not associate such a crude instrument for use by engineers dealing in electronics, were it not for one unusual property of the crowbar. Throw it across a power line, whether accidentally or with a purpose, and the power line trips – a fail-safe arrangement to protect the load in case of an emergency.

In electronics, a crowbar protection is generally an electronic circuitry placed across the outputs of a power supply. It activates to protect the load against overvoltage. When it activates, it shorts the output terminals – the crowbar action. This serves to blow the fuse, trip the circuit breaker or to shut down some part of the circuit so that power to the load is cut off. Most power supplies, whether low- or high-voltage, employ this kind of protection.

The crowbar protection circuit has a sensor that monitors the output voltage of the supply, comparing it against a preset value. When an overvoltage occurs, it triggers the crowbar circuit, which in turn short circuits the output terminals, thereby cutting off power to the load.

Crowbar devices typically use one of two types of components as their main protection. These are the Silicon Controlled Rectifier or SCR, and the Metal Oxide Semiconductor Field Effect Transistor or MOSFET. The design of the monitoring circuit of the crowbar depends on the sensitivity of the load circuit to be protected. For instance, the reaction time of the monitoring circuit depends on how long the protected circuit can survive the excess voltage without damage, and the response time of the main protection device.

Several fault-conditions may lead to possible over voltages. These include a fault in either the power supply or the load, and operator error. Present day electronics are sensitive and often operate at very low voltages with small margin. That makes it imperative to ensure that the safe voltages are not exceeded, and sensitive and expensive equipment remain undamaged.

Although blowing the fuse is a popular method of protecting a circuit, it has its disadvantages. Recovery is only possible by manually replacing the fuse, once the fault condition is repaired. This is a time consuming affair, and not helpful for low downtime appliances. Therefore, most engineers prefer a fold-back type of crowbar protection.

In a typical crowbar protection, the entire load current is diverted from the load and directed to the short circuit across the output terminals. This is constant current limiting and puts the fuse under tremendous stress, causing it to blow, thereby protecting the power supply and its load. In contrast, with the fold-back crowbar protection, the load current through the short circuit reduces once the crowbar has activated and shorted the outputs.

The short circuit current reduces to the extent that the power dissipated by the supply can remain within its safe operating area. This prevents the fuse from blowing, and at the same time, the power supply keeps the load circuit safe because of the crowbar action. As soon as the cause of the overvoltage is repaired, the power supply resumes automatically.

Driving Motors and Servos with the ZeroPi

If you are looking for a development board for the 3-D printer you are designing, ZeroPi may be the best fit. Suitable for use with the Arduino and the Raspberry Pi (RBPi) single board computers, ZeroPi offers an integrated solution allowing makers to build projects easier and faster.

This miniature board for the Arduino and RBPi is a next generation development kit ideal for maker projects that involve any type of robotic motion control including CNC milling and 3-D printers. According to technical specifications, the ZeroPi runs on an Atmel 32-bit, ARM Cortex M0+ processor the SAMD21J18 operating at 48 MHz. This MCU is fully compatible with the RBPi, the Arduino Zero, and so many more hardware resources that drive robots.

Capabilities of the ZeroPi include driving and controlling 11 micro servos and 8 DC motors simultaneously. Alternatively, you can use ZeroPi to control four stepper motors. The four-channel SLOT module is compatible with the regular DC motor and stepper motor drivers such as the TB6612 DC motor driver and the A4988 or DRV8825 Stepper motor drivers.

According to the team that developed ZeroPi, the board works perfectly for a 3-D printer, acting as its mainboard. Additionally, with the ZeroPi and a web interface, it is possible to control the 3-D printer remotely. The team claims to have successfully ported the Repetier and Marlin firmware to ZeroPi. They have tested the combination on Delta and I3 open source 3-D printers, with success. The combination directly controls the printer without requiring any additional expansion boards. Compared to the Mega2560, ZeroPi is all open-source, cheaper and four times faster. In addition, it is only half the size of the Mega 2560. All board schematics, Repetier and Marlin firmware, and the user manual for the ZeroPi is available on GitHub.

Apart from 3-D printers, you can also use the ZeroPi for driving laser cutters and CNC mills. In fact, it is perfectly possible to use the ZeroPi for developing an all-in-one mainboard suitable for all three. This open-source mainboard can serve the creativity and innovation of an entire community, advancing their ambitions. That makes the ZeroPi useful to several people and projects.

Some key features of the ZeroPi are operating voltage of 3.3 V, 2 UARTs, 35 general-purpose IO pins, 4 analog input pins, 12-bit ADC channels, 1 analog output pin, 10-bit DAC. Other features include external interrupts on any pin except pin 4, 7-mADC current per IO pin, Flash memory of 256 KB, SRAM of 32 KB. The ZeroPi board has dimensions of 73 x 61 mm.

You can program the ZeroPi from the Arduino IDE using example codes available for specific functions such as temperature monitoring and encoder readout. By connecting the ZeroPi to the GPIO connector of the RBPi, it is possible to add further functionality such as controlling the ZeroPi via Bluetooth, wireless control, and tablet. By installing a web interface, it is possible to control the motors and servos remotely. The interface can use Java Script as well.

Does the NexDock Work With The Raspberry Pi 3?

Although smartphones are getting smarter all the time, some of their landmark features limit their use as a laptop, two of them standing out prominently. One is the lack of a full-fledged keyboard and the other, a reasonably sized display screen. Therefore, although the smartphone has nearly the same computing powers as your laptop, it fails to compete successfully with a laptop or netbook.

To remedy the situation, you can take recourse to the lapdock. This is a mobile docking station with a built-in battery, a Bluetooth keyboard, and a 14” LCD monitor. While you can connect your smartphone or tablet to the lapdock, it also allows you to dock your single board computer such as the Raspberry Pi or RBPi with equal ease. The lapdock can make use of any device that has an HDMI output.

NexDock is a budget lapdock with a built-in battery that supplies 3.8 V with a capacity of 10,000 mAH. It provides the user with a Bluetooth keyboard, a 14” display, two USB ports, and one micro SD card slot. NexDock has two small loudspeakers built-in, but you can use headphones on the 3.5 mm socket. This is a revolutionary concept helping to harness the productivity of single board computers, tablets, and smartphones.

Single board computers such as the RBPi3 come with an HDMI output. That makes the RBPi3 a suitable candidate for use with the NexDock. As the NexDock uses the operating system of the RBPi, you can use either Linux or Windows 10 easily. An advantage with using the Windows 10 is its Continuum feature, which allows switching between touch and desktop modes. Using NexDock with the iPhone or Android provides the user with a substantial screen size and upgrades the productivity.

This revolutionary budget concept allows you to have the best of both worlds with an SBC, a smartphone, tablet or mini PC. Simply plug in your device and continue to work with it without fear of the battery running out of juice. The massive battery in the NexDock lasts for days on one charge. That means you now have a powerful laptop to take anywhere and do anything along the way. The device measures 351 x 233 x 20 mm, and weighs 1,490 gm. Most of this weight is due to the generously sized battery with a capacity of 10,000 mAH. The display screen is 14.1 inch TN, with a resolution of 1,366 x 768 pixels.

Although the main functionality of the NexDock is boosting mobile productivity, it can also serve to turn your RBPi into a full-fledged computer. However, you can also use it as a secondary portable monitor, a game controller for your iPhone or use it as a dual-screen for AirPlay-enabled games.

For the future, the company is planning to build high-end mini-computers, where you can swap parts. These will have the capability to connect with devices via a single USB-C port. This will serve to reduce the cost of upgrading your computer, as the process serves to separate components that need frequent updates from those that do not. Therefore, while you retain the keyboard, display and the battery, you can update the processor, memory, and operating system as you wish.