Author Archives: Andi

Meca500 – The Tiny Six-Axis Robot

Although there are plenty of robots available in the market for a myriad jobs, one of the most compact, and accurate robot is the Meca500. Launched by the Quebec based Mecademic from Montreal, the manufacturers claim it is the smallest, and most precise six-axis industrialist robot arm in the market.

According to Mecademic, users can fit Meca500 easily within an already existing equipment and consider it as an automation component, much simpler than most other industrial robots are. According to the cofounder of Mecademic, Ilian Bonev, the Meca500 is very easy to use and interfaces with the equipment through Ethernet. With a fully integrated control system within its base, users will find the Meca500 more compact than other similar offerings are in the market.

Mecademic has designed, developed, and manufactured several compact and accurate six-axis industrial robot arms on the market. Meca500 is one of their latest products, the first of a new category of small industrial robots, smaller than most others are, and ultra-compact.

The first product from Mecademic was DexTar, an affordable, dual-arm academic robot. DexTar is popular in universities in the USA, France, and Canada. Although Mecademic still produces and supports DexTar on special request, they now focus exclusively on industrial robots, delivering high precision, small robot arms. With their academic origins, Mecademic has retained the predilection of their passion for creativity and innovation, and for sharing their knowledge.

With the production of Meca500, a multipurpose industrial robot, Mecademic has stepped into Industry 4.0, and earned for itself a place in the highly automated and non-standard automated industry. With Meca500, Mecademic offers a robotic system that expands the horizons for additional possibilities of automation, as users can control the robot from their phone or tablet.

This exciting new robotic system from Mecademic, the Meca500 features an extremely small size, only half as small as the size of the smallest industrial robot presently available in the market. Meca500 is very compact, as the controller is integrated within its base and there is no teaching pendant. The precision and path accuracy of the robot is less than 5 microns, and it is capable of doing the most complex tasks with ease.

Applications for Meca500 can only be limited by the users’ imagination. For instance, present applications for the tiny robot include a wide range, such as animal microsurgery, pick and place, testing and inspection, and precision assembly.

Several industry sectors are currently using Meca500. These include entertainment, aeronautics, cosmetics, automotive, pharmaceuticals and health, watchmaking, and electronics. Users can integrate the compact robot within any environment, such as their existing production line or even as stand-alone system in their laboratories.

The new category of robots from Mecademic is already smaller, more compact, and more precise than other robots are in the market. Mecademic’s plans for the future include offering more space saving, more accurate, and easier to integrate industrial robots. They envisage this will enable new applications, new discoveries, new products, new medical treatments, and many more. Their plan is now to build a greater range of compact precision robots while becoming a leading manufacturer of industrial robots.

How Efficient are Light Emitting Diodes – LEDS?

Almost all commercial and residential establishments are moving over to light emitting diode (LED) illumination, as they are guaranteed to be more efficient compared to other forms of lighting such as incandescent and fluorescent. Unless designed with care, LEDs can suffer from premature failure due to thermal issues. Under thermal stress, LEDs can permanently lose their brightness, while degrading much quicker than the manufacturer intended. That means designers and engineers need to balance the additional cost of emitters with the thermal design for providing not only an elegant design solution, but also the long life that solid state lighting promises.

With roughly 50% of the electrical energy produced worldwide being used for lighting, and the world population growing, the only two alternatives to meet the growing needs of energy are to either generate more or to make more efficient use of what we already have. Generating more energy can take several years to plan and install power plants, but improving the efficiency of lighting can effectively mitigate the rising trend of power consumption.

Providing over 100 lumens per watt, LEDs are being increasingly used for a large selection of general applications. When converting fixture designs for incandescent bulbs to those for LEDs, engineers faced issues because of the difference of their thermal characteristics. For instance, manufacturers publish the life curves for LEDs as a function of temperature, while fixture designers do not know how to handle the information.

Incandescent bulbs were actually heaters that emitted some visible light. Nearly 90% of the light emitted by incandescent bulbs fell into the region beyond 700 nanometers—the infrared region—invisible to the human eye, but perceptible as heat. This would often cause problems in the kitchen, with waste IR light promoting premature spoilage in food illuminated by incandescent bulbs.

LEDs produce light via a different mechanism. When electrons in the LED junction cross over a forbidden energy zone called band-gap and combine with holes, they produce light because the electrons lose energy. Physicists tailor the energy by adjusting the width of the band-gap, thereby producing various frequencies of light. For instance, a white LED actually generates intense blue or Ultra Violet light, which then excites a phosphor placed in its optical path, thereby turning it into white light.

However, the process of converting electrons to light photons within the junction of the LED is not a perfect one. A vast majority of the photons created within the junction is never emitted and ultimately recombine to produce waste heat. Additionally, Stokes Shift, the phenomenon that shifts the frequency of the LED emission in the phosphor to produce white light, also generates waste heat. Waste heat from both of these mechanisms must be removed from the LED junction to prevent severe damage.

Unlike their incandescent predecessors, LEDs rarely fail catastrophically. Their slow degradation affects the photon emission mechanism, resulting in a dimming effect. Engineers use two industry end-of-life metrics for measuring the life of LEDs. One is the L70 or time taken to reach 70% of original emission, and the other is L50 or time taken to reach 50% of the original emission. The industry uses the L70 point as the useful life of an LED fixture or bulb.

What is Cabinet-Free Motion Control?

Controllers, drivers, and servomotors usually control automated platforms and machines in the automated production industry. With the evolvement of technology for machine motion, control and driving of individual machine axes is being increasingly taken over by highly intelligent electronics. Therefore, the control cabinet is assuming the central role with the rest of the system being designed around it.

With the rest of the machinery developing much more slowly, the faster evolving complex automation design and development becomes a cost-constraint for the OEM, system designers, and end users. Control cabinets need redesigning, especially with the increasing numbers of servo-driven axes. Typically, the location of the control cabinet is relatively fixed on the machine, which limits the manufacturers’ ability to modify and update the footprint of their machines.

As a solution to the above constraints, system designers are moving towards a new concept where the motion control and servo-drive mechanism is distributed rather than bound within a physical cabinet. By locating the controllers, servo drives, and power supplies nearer to the motors and axes they control, OEMs and system designers overcome several challenges arising from installation, cabling, and multiple engineering.

Initially, system designers had reoriented their designs in attempting to drive multiple machine components with a single servo motor. Although this approach had the benefit of reducing the physical number of servo motor and drives, it required a larger motor with higher power to handle the load, and several additional mechanical components for delivering the centralized power. A Cartesian motion system with a single motor for a palletizing application is an example of such a centralized approach.

By separating the servo motors on each axis, mounting them on the independent frames, and driving them separately, system engineers were able to use smaller motors, thereby reducing the overall power requirement, and developing a solution with higher efficiency.

One of the barriers to cabinet-free motion control architecture comes from PLC limitations. By limiting the axis count supported by their PLCs to 16 or 32 axes, some manufacturers force users to purchase a second PLC, which means addition of a more expensive control box with higher capacity.

For some time now, OEMs have been following a common practice of moving power supplies, servo drives, and related devices out of the control cabinet and placing them closer to each motor and its drive axis. This trend began with several leading suppliers introducing electric motors with their drives integrated into the motors’ housings. This required control electronics to be shock and vibration resistant as well as capable of withstanding the higher temperatures usually associated with environment outside the control cabinet.

Recent advances of cabinet-free components include separate ac-to-dc power supplies, independent drive units capable of mounting close to the servomotor on the machine, and power cables integrating communication capable of daisy-chaining several drive-integrated servomotors into a single circuit.

A further introduction of newer motion controllers or PLCs is helping the cabinet-free technology portfolio. These integrate the controller hardware into modules capable of mounting on the machine along with the necessary power supplies and drives. This eliminates the requirement of a control cabinet entirely.

BrailleBox with the Raspberry Pi

Reading, whether online or from the page of a book is a simple affair for those endowed with the power of sight. However, for those who are sightless, or have lost their eyesight, totally or partially, reading can be cumbersome, if not impossible. The Braille system, by allowing a changeover to the sense of touch, helps sight-impaired people to read.

Braille uses a system of raised dots that blind or those with low vision can follow with their fingertips. It is not a separate language, but rather a code for representing individual alphabets of a language. So far, the Braille system covers several languages, including Chinese, Arabic, Spanish, English, and dozens of others. Thousands of people all over the world use the Braille system of dots in their native language, providing a means of literacy for all.

The main code for reading materials in the US is the Unified English Braille, and seven other English-speaking countries use this code.

As such, Braille is useful when the material is in printed form. However, the challenge lies in reading online material. Although text-to-speech software packages are available, they are expensive and not very useful when the reader, say, wants to move back and forth while reading.

As a solution to the above problem, Joe Birch has built BrailleBox, a simple device to convert online news stories to Braille. His BrailleBox works with Android Things, News API, and the popular single board computer, the Raspberry Pi 3 or RBPi3.

Being a symbol system for people with visual impairment, the Braille system consists of letters and numbers as raised points in an array. Commercial systems are available and they produce Braille dynamically, but they are very expensive and out of reach of most people. Therefore, Joe built a low-cost alternative, the BrailleBox, which is simple to create.

Joe uses the News API as a tool that fetches jSON metadata from more than 70 news sources online. The API can integrate articles or headlines into text-based applications and websites.

The Braille system uses an array of six dots arranged in an array of three rows and two columns. Apart from representing the alphabets and numbers with various combinations of the six dots, they also represent whole words, sometimes in contraction. For instance, contracted braille includes 75 short form words and 180 different letter contractions. These help to reduce the volume of paper necessary for reproducing books in Braille.

To make the six dots for forming the Braille symbols, Joe attached wooden balls atop solenoids. He arranged the solenoids in an array of 2×3, and wired them individually to GPIO pins of an RBPi3.

Being an Android engineer, Joe controls the solenoids through Android Things, running on the RBPi3 as self-booting BrailleBox software. The reader has to push a button, which makes the program fetch a news story using the News API. As the RBPi3 deciphers the alphabets, it operates the solenoids, moving the dots.

Joe’s project is still in prototype stage, and he is yet to move all hardware inside a proper box. He also wants to add a potentiometer, preferably foot operated, so the readers can set their own reading speed.

Industrial Motors for Machine Automation

Industrial engineers use different types of motion control devices for improving the production rates and efficiencies on the floor of automated factories. Three major types of motion control devices are in demand for machine automation—stepper motors, servomotors and variable frequency drives (VFDs).

In general, stepper motors along with their drives, and controllers are widely used as they offer simple implementation, beneficial price/performance ratios, and high torque at low speeds. This motor is essentially a brushless DC version, moving in equal fixed steps during rotation, and only a single step at a time. Not requiring tuning or adjustments, stepper motors provide very high torque at speeds below 1000 RPM. They are cost-effective, as their prices are substantially lower than the cost of comparable servo systems. Since the torque they produce decreases as they speed up, it makes their operation difficult. Therefore, the work done by stepper motors becomes impractical at speeds in excess of 1000-1500 RPM.

Servomotors come with a motor, drive, a controller, and a device for positional feedback. For variable load applications, engineers prefer them to stepper motors, as they deliver high torque when rotating at speeds above 2000 RPM. Servos require adjustments and tuning, making them more complex to control compared to stepper motors. Including maintenance costs, their positional feedback arrangement can push their prices well beyond those of stepper motors.

Costing less than stepper motors or servomotors, VFD systems include an AC motor and a drive, but are unable to provide positioning. However, they can be good for applications requiring speed control on variable loads. For applications where the motor need not run continuously at full load, a VFD system can save considerable amount of energy. Another feature of VFDs is their soft-start capability, allowing a limit to high inrush currents.

In a stepper motor system, the controller regulates the position of the step, the torque generated by the motor, and the speed of the motor as it moves from one step to another. The driver operates on the control signals the controller generates by modifying and amplifying these signals to regulate the direction and magnitude of the current flowing into the motor’s windings. This way, it drive rotates the shaft of the motor to its desired position, and holds it in position with the required torque for the required time.

Controllers for stepper motors can be either open or closed loop types. Open-loop controllers are simpler, not requiring any feedback from the motor, but are less efficient. Open-loop controllers operate on the assumption the motor is always at the programmed step position and is producing the desired torque.

On the other hand, closed-loop controllers always operate with feedback based on the effective load on the motor. Therefore, the performance of the closed-loop stepper motor controller is similar that of a servo motor, and makes the operation more efficient.

Making a stepper motor rotate through each of its steps requires energizing the several windings within the motor in a specific sequence. Typically, stepper motors rotate 1.8 degrees per step, necessitating 200 steps to make a complete revolution.

What is Open Bionics?

There are people all around the world that may loose limbs for various reasons — wars, illness, and accidents being the three major ones. Artificial limbs do alleviate a part of the loss these folks experience, but often, their high cost means not all can afford a prosthetic limb. Open Bionics is a company making affordable bionic arms, making kids feel like superheroes.

A start-up tech company in the UK, Open-Bionics is changing the way people see prostheses. The 3-D printed prostheses Open Bionics makes are nearly 30-times cheaper than those available in the market are. Their biggest advantages are the myoelectric sensors that attach to the skin for detecting muscle movements. Detection of muscle movement controls the artificial hand in closing and opening fingers.

The bionic arms that Open Bionics makes are custom-built for individual children and require about 40 hours for manufacturing them. As the child grows, a revolutionary socket adjusts to the changing size. As these are small and lightweight, children as young as eight can use the bionic arms with ease.

According to the COO and co-founder of Open Bionics, Samantha Payne, they work with the NHS for creating prosthetics that are affordable and highly functional. These are meant especially for children, and come with removable covers—allowing them to choose whether they want to be Queen Elsa, or an Avenger today.

The company has a royalty-free agreement with Disney. That means they can base the removable covers on the bionic arms on characters from Star Wars, Frozen, Iron Man, and more—this can be life changing for small children, as Samantha Payne assures. For instance, Tilly Lockey, who is testing the latest model from Open Bionics, has a prototype hand themed on Deus Ex, a video game.

Open Bionics builds assistive devices offering people who use them greater freedom and independence. Moreover, as the devices are affordable, it brings bionic technology within the reach of most patients. That is why trials of bionic arms are reaching children as young as eight.

Most available prostheses do not suit young patients, as they are either way too big or very expensive. The 3-D printed bionic limbs from Open Bionics are different as they are custom-built to suit small sizes, and they are affordable. Samantha Payne feels highly satisfied seeing a young child moving their fingers individually for the first time.

Rather than making a drab skin-colored artificial limb, Open Bionics is making their arms belong to the science fiction universe. With themes from Star Wars, Disney, and Marvel, kids feel proud when wearing their prostheses. As these arms are sleek and super stylish, amputee children can identify them with their personalities and that is what makes them and the people at Open Bionics so excited.

At Open Bionics, the task begins with scanning the person’s limb using a tablet. A plan for the design of the prostheses follows, leading to a 3-D printout. The result is a low-cost, multi-grip, and lightweight bionic arm with great control. The royalty-free theme designs make the device hyper-personalized. The presence of nearly 5 million upper-limb amputees worldwide gives an estimate of the market potential for Open Bionics.

How are RS232 and RS485 Different?

When engineers need to connect electronic equipment, they resort to serial interfaces such as the RS-232 and RS-485. Although dozens of other serial data interfaces exist today, most are meant for use in specific applications. A few of them are considered universal, such as I2S, MOST, FLEX, SPI, LIN, CAN and I2C. Other high-speed serial interfaces are also used, including Thunderbolt, HDMI, FireWire, USB, and Ethernet. Despite the proliferation of interfaces, the two legacy interfaces, RS-232 and RS-485, continue to survive, used in several applications.

As a rule, serial interfaces provide a single path for data to be transmitted over a cable or wirelessly. Although some applications do use parallel buses, serial interface alone provides the only practical option for high-speed data movement today over any distance greater than several feet.

RS-232

RS-232 is one of the oldest serial interfaces, originally established in 1962, as a method of connecting a DTE or data terminal equipment such as a teletypewriter to a DCE or data communications equipment. Personal computers earlier had an RS-232 port, commonly called the serial port, to connect to a printer or other peripheral device. Embedded computer development systems still use the port today, as do many scientific instruments, and several industrial control equipment.

Officially, the standard defining the RS-232 serial interface is the EIA/TIA-232-F, with F signifying the most recent update. According to the standard, a logic 1 is defined as a voltage between -3 and -25 V, and a logic 0 as a voltage between +3 and +25 V. The logic 1 is generally termed as a mark, with logic 0 being termed as a space. Any voltage between +3 and -3 V is termed invalid and is rejected, providing a huge noise margin for the interface. The configurations of the receiver and transmitter are both single-ended and referenced to ground or 0 V.

The cable medium in RS-232 can be simple wires in parallel or a twisted pair. According to the standard, the cable length must not exceed 50 feet. However, by reducing the data rate, it is possible to use longer lengths of cable. For a 50-foot cable, the highest data rates in RS-232 are roughly 20 Kbits/s, and matched generator and load impedances are necessary for eliminating reflections and data corruption. Although earlier 25-pin connectors were used, the de-facto standard for RS-232 is the 9-pin DE-9 connector today.

RS-485

The EIA/TIA standards also define the RS-485 interface, now commonly known as TIA-485. This is not only a single device-device interface, but is a complete communication bus used for simple networking of multiple devices.

Rather than a single-ended voltage referenced to the ground, the RS-485 uses differential signaling on two lines. A logic 1 is a voltage level greater than 200 mV, while the logic 0 is a level greater than +200 mV. The maximum cable length for RS–485 is about 4000 feet or 1200 m, with typical data rates as 100 Kbits/s. However, compared to the speed of the RS-232 interface, a 20-meter cable in RS-485 can allow a maximum data rate of 5Mbits/s. Industrial control equipment using the RS-485 use the 9-pin DE-9 connector.

Raspberry Pi Controls the Cardboard Dog

This is a project for beginners using the Raspberry Pi (RBPi) single board computer. The RBPi is used to control a servo for turning the head of a cardboard dog away whenever a person is looking at it. This is to mimic a begging dog that seems ashamed of its begging nature.

This project requires the SBC RBPi, its power supply with the 5 V micro-USB cable, a USB keyboard and mouse, a display, and an HDMI cable. For storing the OS, an 8 GB micro SD card is also necessary. Another computer will be necessary to write the OS to the micro SD card and edit the files in it. The official PI camera will help to recognize the faces looking at the dog, and a micro servomotor is required to turning the head.

The RBPi will be controlling the servo through its GPIO pins. The servo has three wires that need to connect to the GPIO pins using female connectors. The camera has a ribbon cable, which goes into the port labeled camera on the RBPi. The HDMI cable goes into its port on the outside of the RBPi, and its other end goes to the HDMI-compatible TV or monitor.

Download and install the latest version of the Raspbian (with Pixel) from the official website of the RBPi. While installing the image on to the micro SD card, the process will destroy all data on the card, so be sure there is nothing of value before you begin.

Once the OS is installed on the micro SD card, insert it into the slot on the reverse side of the RBPi. If the power cord is now plugged into the RBPI socket and the power turned on, there should be some code running on the monitor screen, with the desktop showing up at the end. At this time, right click anywhere on the desktop and select “Create a New File.” Name the file Dog Turn.py, and select it to open with Python 2 IDLE.  Now open IDLE, and paste the code from here into it.

To make the code in the file to work, the RBPi will need additional Python modules to be installed. These are the libopencv-dev, python-opencv, python-dev, and you must use the sudo apt-get install command to download them.

The cardboard dog for this project uses four 9×6 inch cardboard rectangles, and two 6×6 inch squares, which form the main body. A hole at the top of the box allows the servo to go through. Another 5-inch cardboard cube forms the head, and attaches to the servo. Some cardboard legs make the dog look more realistic.

The entire electronic hardware can fit within the body of the dog. It may be necessary to use standoffs to hold the RBPi in place. The camera should look out from one of the eyeholes in the dog head. Fix it in place so that the cable has sufficient play when the servo moves the head. Simply running the python code should be enough to let the dog do its trick. To stop, turn off the power.

What are Current Sense Resistors and how do they work?

Efficiency has become the keyword in global trends in meeting demands for lower carbon-di-oxide emissions. Whether it is the smartening of the electrical supply grid or the electrification of our automobiles, the global trend is driving the need for electronic circuits to become more efficient. Knowing the level of current flowing through the circuit and reaching the load accurately is an important factor in gauging its efficiency for circuit designers and systems operators. This knowledge helps in maximizing operating performances of a battery, hot swapping server units, controlling motor speeds, and many more. Current sense resistors are inexpensive components that provide optimal solutions helping OEMs create more efficient circuit designs for a wide range of applications.

Current sense resistors are components helping to improve system efficiency by reducing losses. They have high measurement accuracy compared to other technologies, and they are ideally suited for helping developers measure currents precisely in automotive, industrial, and computer electronic designs.

Current sense resistors detect and convert current to voltage, using Ohm’s law. According to this law, the product of the current and the resistance value through which it is passing gives the voltage developed across the resistor. As these resistors feature very low resistance values, the voltage drops are equally insignificant, of the order of 10 to 150 mV in specific applications.

Design engineers place the current sense resistor in series with the electrical load, which causes the entire current to be measured to pass through it. As the voltage drop across the resistor is proportional to the current through it, measuring this drop provides an estimate of the load current. Measuring the voltage drop is usually accomplished through various amplifier options such as operational, differential, and instrumentation amplifiers. Selecting the right current sense resistor amplifier for a specific application involves looking at the input common-mode voltage specification. This is the average voltage present at the input terminals of the amplifier.

With the current sense resistor sitting in series with the load, they can directly measure the current. Contrast this with indirect current measurement techniques using coils. Here the voltage is induced across a coil and is proportion to the current. As a series resistor senses current directly, it dissipates power. Therefore, series resistors tend to have very low resistance values.

Current sense resistors also feature a very low temperature coefficient of resistance or TCR. This feature defines its low drift with varying ambient temperature and its long-term stability. These characteristics make temperature dependency of current measurement to be very low, while increasing the accuracy.

However, when using very low ohmic resistors of the surface mount type the resistance of the solder pad and the copper tracks of the printed circuit board can be uncertain and more than the resistance of the current sense resistance itself. This can lead to inaccuracies in the current measurement. In addition, the TCR of the tracks of the PCB can be much higher than that of the series resistor element.

Therefore, it is necessary to use current sense resistors implementing the 4-wire Kelvin principle, as these employ additional leads for measuring current more accurately.

Why Smart Home Tech Adoptions Need Switches

Most modern homes now use connected devices for entertainment, access control, and several other daily tasks. Their rapid increase can be gauged from the growth of the US market for smart homes, which has reached 29 million and is still rising.

The amazing features and efficiencies products related to smart homes offer to households naturally mesmerize consumers. However, this also necessitates engineers keep in mind the physical interfaces. While customer satisfaction is a long-standing effect, the immediate look and feel of the device dictates its price. This implies details are an important aspect, where the choice of every component matters and that includes switches and buttons.

Most people tend to ignore switches and buttons, forgetting they are responsible for driving the technical movement known as smart homes. However, a few important reasons establish engineers designing home products must give them a serious thought.

The connected devices in a smart home depend critically on their hardware designs. These include switches, sensors, screens and other components used on smart televisions, smart thermostat controls, connected door locks, and more. Most importantly, a user’s overall satisfaction comes from the way a product feels or the tactile sensation it generates.

Most of the time, a customer’s first interaction with the control of a product comes from its on/off switch, which a user physically touches. Unless the switch creates a delightful experience, the customer is likely to search for another product that offers a better feeling.

Cameras working on the Internet Protocol are now commonly available in smart homes. The reason for this is easy to figure out, as according to the statistics provided by iControl Networks, there is a burglary happening every 14.1 seconds in the US. With an IP camera installed, a person can monitor the activity at home from a remote location on their smartphones, laptops, or any other smart device. The very presence of IP cameras act as a deterrent to crime, apart from helping the police apprehend criminals, while simply providing a piece of mind to a homeowner.

However, smart cameras need the right switch to power and protect them. Usually, this is a miniature tactile switch, suitable for meeting the shrinking form factors of the device. Often smaller than the small lens display used by these cameras, the switch must be robust enough to prevent intruders from breaking it and rendering the camera useless.

While IP cameras capture images of unwelcome intruders whom people are not suspecting of entering their homes, access controls offer an additional level of security to the majority of consumers concerned with privacy and security in their smart homes. Access controls are usually equipped with internet doorbells with built-in cameras, and smart door locks.

While the camera shows an image of the person at the door, the smart lock allows unlocking the door remotely. This arrangement can be handy if the door has to be opened for the baby sitter or for the teenager who has misplaced his keys. Usually, the smart lock has a miniature switch to set or reset it. This switch has to be small but long lasting, and able to withstand harsh conditions such as humidity and rain.