Monthly Archives: May 2018

ASUS Tinker Board Competes with the Raspberry Pi

With the advent of the Raspberry Pi (RBPi), the popularity of single board computers (SBCs) has risen rapidly over the last five years. The RBPi has easy software and a low price that has won it a vibrant community consisting of not only coding hobbyists, but also teachers and children, whose minds and hearts it has captured. This success of the RBPi has led to scores of other vendors pitching in with their SBCs. Among them, ASUS is the latest with its Tinker Board SBC, challenging the RBPi.

The Tinker Board from ASUS offers an SBC with somewhat higher premium hardware compared to that offered by the RBPi. According to ASUS, its Tinker Board tries to meet the demands of enthusiasts who are looking for better performance. Although their efforts are commendable and they have created a great piece of hardware, the real hurdle they have yet to overcome are the software and support.

If you are not careful with the Tinker board, at first glance you might mistake it for a more colorful RBPi. However, the tweaks exhibited by the Tinker Board design makes it feel more like a premium product. For instance, icons covering the board depict its various functions, such as they clearly differentiate between the display and the camera connectors.

Color-coding on the Tinker Board helps identify most of the pins on the general-purpose input/output (GPIO) header. For instance, the +5 V pins are all colored red, while the ground pins are black. Moreover, ASUS has maintained the same pin configuration for the GPIO as that followed by RBPi. Therefore, transferring your projects over to the Tinker Board is very easy. The Tinker Board comes with a stick-on heatsink. This is really helpful as, under load, its SOC runs far hotter than that of the RBPi does.

The Tinker Board sports a faster system-on-chip, the Rockchip RK3288, a quad-core running at a maximum frequency of 1.8 GHz. Not only is this faster than that of the RBPi3, the Tinker Board also has double the RAM. On the ASUS site, they have benchmarks to show the speed of the Tinker Board as far above its competitor, the RBPi. Comparatively, the site claims double the CPU power and GPU performance over that of the RBPi.

Apart from the faster chip and the extra RAM, ASUS has also added the Gigabit Ethernet connector in place of the 10/100 Ethernet of the RBPi. The Tinker Board also has an uprated sound chip and an upgradable Wi-Fi antenna. According to ASUS, the performance of the USB storage is superior and the operation of the SD card is faster. ASUS attributes this to the dedicated controller of the Gigabit Ethernet, which does not allow any reduction in LAN speed during USB data transfers. Comparatively, the RBPi has a USB-to-Ethernet bridge, which makes the two functions interdependent.

However, unlike the Tinker Board, the RBPi has a website full of useful information. The RBPi also has the NOOBS installer, which simplifies installation of a number of operating systems. Comparatively, the website of the Tinker Board has two images, one for the Debian-based Tinker OS, and another based on Android.

Inertial Sensing for Automation

In any type of industry, whether it is automotive, unmanned aerial vehicles, energy, logistics, agriculture, or manufacturing, automation brings increasing promises of great gains in terms of efficient utilization of resources, achieving accuracy, and safety. To achieve these gains it is necessary to identify the appropriate sensing technologies that will enhance the contextual knowledge of the equipment’s condition.

As the location or position of an equipment is a valuable input, precision inertial sensors provide accurate location information and help in maintaining accurate positioning. Where mobility is a factor, it is necessary to couple both the location and the contextual sensor information with the application. Operating in a harsh or complex environment often requires determination of position as a critical value. This is where inertial sensors help to make a difference.

Over the years, machinery has evolved from making simple passive movements, to functioning with embedded controls, and now it is moving towards fully autonomous operations, with sensors playing the enabling role. Earlier, for supporting offline analysis or process control, sensors working in isolation were adequate. However, obtaining real-time benefits requires increasingly sophisticated sensor types, while efficient processing requires important advances in sensor fusion. Therefore, increasingly intelligent sensor systems are coming up catering to complex systems on multiple platforms that require the knowledge of states the system has held in the past.

Inertial sensors used with smart machines serve two special functions, one for equipment stabilization or pointing, and other for equipment navigation or guidance. Most systems consider GPS as the most suitable for navigation. However, potential blockages cause significant concerns for many industrial systems. Some systems transition to inertial sensing when GPS is blocked, but this requires the inertial systems to be of sufficient quality to provide the same precision, as did the GPS.

Inertial sensors provide the feedback mechanism in case of servo loop or stabilization for maintaining a reliable positioning such as the antenna pointing angle, construction blade, crane platform, camera, UAV, or farming implement. For all these, the purpose is not only to provide a useful function, but also to deliver a safety mechanism or critical accuracy, even when the environment is incredibly difficult.

In reality, sensor quality matters when good performance is desired. Engineers use sensor fusion for making some correction, for instance, when correcting the temperature drift of sensors, or compensating an accelerometer when correcting for gravitational effects on a gyroscope. In such cases, this helps only in the calibration of the sensor to the environment, but does not improve the ability of the sensor to maintain performance between the calibration points. With a poor quality sensor, the accuracy falls off quickly, as the performance of the sensor rapidly drifts without expensive or extensive calibration points.

Even when using high quality sensors, some amount of calibration is desirable, especially when the aim is to extract the highest possible performance from the device. However, the most cost-effective method of calibration depends on the intricate details of the sensor, along with a deep knowledge of motion dynamics. This makes the compensation or calibration step an embedded necessity for the manufacturer of the sensor.

Specifying Fiber Optic Sensors

The industry prefers fiber optic sensors as they work well in tight spots and in applications that have a high degree of electrical noise. Fiber optic sensors are useful in machines, fixtures, and conveyors for sensing part presence as an important component of industrial automation. The industry often requires controlling sequence and error-proofing assembly based on the presence or absence of a part. In many cases, it is simply impossible to know whether a part is where it should be or the holder is empty as expected. Therefore, verification is only possible by using a presence sensor.

Sensors come in many varieties, including magnetic, capacitive, inductive, and photoelectric. Depending on the application, each type of sensor has its own merits and demerits. Among all the sensors available in the market, photoelectric sensors offer the broadest types and technologies, and suitable for the widest range of applications.

The family of photoelectric sensors includes a large variety of light-emission types that includes lasers of class 1 and 2, visible, and infrared. They also include different sensing technologies such as through-beam, reflective, suppression, background, and diffuse. Different housing configurations are also available such as fiber optics and photo eye. We will focus on specifying and applying fiber-optic sensors, as these offer the most advanced capabilities with options for configuration, and are most suitable for use in tight spots that the photo-eye sensor finds too small.

Fiber-optic sensors are also known as fiber photoelectric sensors, and comprise of two parts—the amplifier and the fiber cable. The amplifier is the electronic part and is actually a fiber photoelectric amplifier. The fiber-optic cable includes the optic sensor head and the fiber cable to transmit light to and from the amplifier.

All photoelectric sensors work with a simple technique. A light emitter produces the source signal and a receiver detects the signal. A large variety of technologies is available for sensing and measuring the light transmitted to the receiver. For instance, standard photo-eyes look for the presence or absence of light, whereas background suppression sensors sense the angle of the returning beam. Other type of sensors measure the time taken by the light to return, thereby providing a measure of distance it traveled.

Simple photo-eyes such as those used in reflective and diffuse units house the emitter and receiver in the same optical sensor head, while through-beam units house them in two optical sensor heads. On the other hand, fiber-optic sensors have all the electronics in a single housing, with a fiber cable connecting the separate emitter and receiver to the electronic housing. Light from the emitters and that coming to the receivers travels through the fiber cables, similar to high-speed data traveling through fiber-optic networks.

The above segregation means the technician has to mount only the sensor head on the machine, while routing the integrated fiber-optic cable and plugging it into the amplifier placed in a safe place such as a control enclosure to protect it from the harsh manufacturing environment.

A large variety of options is available for both fiber-optic cables and amplifiers. These range from basic to advanced, suitable for meeting the demands of increasing functionality, including advanced logic and communication capabilities.

Using Raspberry Pi to Monitor the Environment

Many cities in the world are plagued with poor quality of air caused mostly by pollution form old diesel cars. This is true of Peru also, and James Puderer is using Raspberry Pis (RBPis) fitted in several taxis to monitor the air quality. James fitted the RBPis in the hollow vinyl roof sign almost all taxicabs use in Peru.

James uses the RBPi along with various Adafruit technologies, such as the BME280 sensor for temperature, humidity, and pressure. He has created a retrofit setup powered by a battery and GPS antenna that fits snugly into the hollow of the vinyl sign.

The completed air-quality monitor collects data on latitude, longitude, pressure, temperature, humidity, and airborne particle count. The data enters a data logger, which then pushes it on to the Google IoT Core, from where any computer may access it remotely.

At the Google IoT Core, Google Dataflow processes the data and turns it into a BigQuery table. Any user can then visualize the measurements the monitor collects, using several online tools available to study them and organize to figures depending on the results he or she expects to achieve. For instance, James uses Google Maps to analyze the data and produce a heat map of the local area that includes air quality.

On his project page, James provides the complete build process for the air quality monitor using the RBPi. This includes the technical ingredients and the code he developed. He also urges others to make their own air quality monitors for their local environment. His plans include designing an additional 12 V power hookup, which will enable connecting the air quality monitor to the battery of the vehicle. He also plans to include functioning lights when the air quality monitor is inside the sign, and companion apps for the drivers to use.

Others have also used the RBPi with sensors to track the world around it. This includes the Human Sensor costume series by Kasia Kolga. The dresses react to the air pollution by lighting up. Kasia created the Human Sensor in collaboration with Professor Frank Kelly and other environmental scientists at the King’s College, London.

Linked to an RBPi and a GPS watch, a small aerosol monitor is hidden within each suit of the Human Sensor costumes. These components work together and gather the pollution data at their location. Although the suits store their collected information to submit it later, in future the suits will be relaying the data in real time to a website for the public to access.

The RBPi works to control the LEDs attached to the suit. In reaction to the air conditions detected by the monitor, the RBPi flashes the LEDs, makes them pulse, or produce patterns and colors that morph accordingly.

Depending on the negative or positive effect of the air around the monitor, the suit’s LED system responds to the absence or presence of pollutant particles. For instance, when the wearer walks past a grassy clearing in a local park, the suit will glow in green colors to match it. As soon as the wearer goes behind the exhaust fumes of a car, the suit will pulsate with red light.

What is USB Type-C Interface?

All new electronic devices are now coming with the USB-C interface, and this is revolutionizing the way people charge the devices. So far, most electronic devices had the micro-USB type-B connectors. With the USB Type-C connector, it is immaterial what orientation you use for the charging cable—the non-polarized connector goes in either the right side up or upside down. The connecting system is smart enough to figure out the polarity as a part of the negotiation process, and supports bidirectional power flow at a much higher level.

Earlier, the USB connectors handled only the 5 VDC fed into them. The USB-C port can take in the default 5 V, and depending on the plugged in device, raise the port voltage up to 20 V, or any mutually agreed on voltage, and a preconfigured current level. The maximum power delivery you can expect from a USB-C port is 20 V at 5 A or 100 W. This is more than adequate for charging a laptop. No wonder, electronic device manufacturers are opting for incorporating the USB-C into their next-generation products.

With the increasing power delivery through the USB Type-C ports, the computer industry has had to raise the performance requirement of the voltage regulator. Unlike the USB Type-B and the USB Type-A fixed voltage ports, the USB Type-C is a bidirectional port with a variable input, and an output range of 5-20 VDC. This adjustable output voltage feature allows manufacturers of notebooks and other mobile devices to use USB Type-C ports to replace the conventional AC/DC power adapters and USB Type-B and A terminals. Manufacturers are taking advantage of these features and incorporating dual or multiple USB Type-C ports into their devices.

However, using the current system architecture for implementing dual or multiple USB Type-C ports, leads to a complicated situation. It is unable to meet many requirements of the customers. As a solution, Intersil has proposed a new system architecture using the ISL95338 buck-boost type of regulator, and the ISL95521A, which is a combo battery charger. Use of these devices simplifies the design of the USB-C functions and fully supports all features. Applied on the adapter side, manufacturers can implement a programmable power supply, and it offers an adjustable output voltage that matches the USB-C variable input voltage.

In the proposed design, Intersil offers an architecture with two or more ISL95338 devices in parallel. Each of them interfaces a USB Type-C port to the ISL95521A battery charger. As this architecture eliminates several components from the conventional charging circuit, including individual PD controllers, ASGATE and OTG GATEs, it saves manufacturers significant costs. For charging a battery, power is drawn directly from the USB-C input to the ISL95521A, and the multiple ISL95338s offer additional options.

For instance, the user can apply two or more USB-C inputs with different power ratings for charging the battery fast. Therefore, the battery charge power is now higher than that supplied by a single USB-C input power. It also means there is no need for adding external circuitry to determine the different power rating operations of the paralleled ISL95338 voltage regulators.