Monthly Archives: February 2015

Wireless charging – what’s new?

The convenience of having your mobile charged wirelessly, while you sip coffee at the corner shop, is now fast approaching reality with passing time. Wireless charging is now entering a phase where manufacturers are turning up the power so that it is possible to charge wirelessly handheld medical equipment, tablets and larger phablets. For example, a new set of receivers and transmitters from Freescale can now handle up to 15W. These chips use the Qi technology that the Wireless Power Consortium has defined.

According to the MCU group director of global marketing and business development at Freescale, the latest mobile products are offering a broader range of features. As compared to earlier, current products have bigger form factors and improved functionalities, necessitating larger batteries. Accordingly, wireless charging systems must also upgrade to accommodate the larger power requirements and faster recharge speeds.

Freescale’s transmitter chips – WCT1012/WCT1111 – are available as standard and premium versions. Together with the receiver chip – WPR1516 – Freescale now offers wireless charging system for mobile and other devices with bigger batteries. Compared to their 5W predecessors, the new chipsets from Freescale can recharge more than three times faster.

The typical 5W charging system produces one ampere of current, allowing charging to be completed in one hour. The new chips handle 15W and theoretically, should cut down the charging time by a third because of improved power handling capacity.

Modern smart devices such as the Samsung Galaxy Tab and the Apple iPad have power ratings reaching 12W, but existing wireless charging devices cannot handle this power. According to IHS Analysts, fast charging capabilities are expected to grow rapidly in and after 2015. The new 15W specifications will accommodate such devices allowing them to be charged faster.

Manufacturer’s feel that a 15W wireless charger has more value since it is able to charge simultaneously many devices belonging to different power classes in multiple scenarios. Compare this to a charger that targets charging only media tablets. For example, the new wireless chargers will charge not only your media tablets consuming 12-15W, but also manage the charging of your phone at standard or fast charging and a wearable device consuming 0.5 to 3W or more. That certainly makes it a valuable product to own.

Inside the Freescale transmitter is a 100MHz DSC core that consumes less than 30mA loop current. DSP functionality within the core helps to reduce the system losses and improve its capability for charging. Additional programmability built into the premium transmitter provides access to flash memory on the chip. Extra IOs on the transmitter device allows building of applications such as chargers that support multiple devices at the same time. On the other hand, the Freescale receiver has capabilities to support buck output and LDO power topologies.

The Freescale chips work on magnetic induction principles using closely coupled coils. The chips comply with two standards – Qi and another specification from the Power Matters Association. However, the Freescale devices are not compatible to the resonant standard using loosely coupled coils that the Alliance for Wireless Power follows. According to Freescale, inductive charging is healthy for the ecosystem.

Fun projects for the Raspberry Pi Model A+ – Part 1

Fun Projects for the Raspberry Pi Model A+ – Part 1

The latest release of the Raspberry Pi, the RBPi Model A+ is not only smaller, it is cheaper as well. That makes it an ideal device for taking a plunge into coding and for trying out new projects. Here are some fun projects that you may find interesting.

A Garden with Digits

With a Pibrella add-on board, your RBPi can run several small motors to create a digital garden. Define the garden to your exact specifications with ornate flowers that you could make out of card or cloth. Add artificial bees and make then spin when you press a button. You could also arrange a relaxing setup of plants and have some soothing music going on at the same time. For details, look here.

Juggle With Illuminated Pins

This is for those who like to juggle things. While juggling, let your RBPi help you out with the routing using some extra LED lights. You will need a Pibrella board and some custom Python code to make the project work independently. Although this may be a niche case, the project is worth undertaking. Lauren Egts has a blog post.

Console for Retro Games

Arcade cabinets of yesteryears still draw a lot of interest. Both young and old enjoy retro games and your RBPi can work as the basis for such a console. With RetroPie, you can simply load emulator software. All you need is an SD card and some USB peripherals. This simple but fun project can be completed within one hour. Life hacker has a guide.

Control Your Pottery Kiln via Wi-Fi

Those using kilns for firing up potteries will find this project useful. RBPi provides remote capabilities for automatic temperature control using a thermocouple and a stepper motor. Temperature stability is maintained with a system of closed-loop feedback. Visit the RBPi blog for code and photos.

Watch Birds with Infrared

Although this is a project for birdwatchers, others can adapt it for their own requirements. An RBPi makes it possible to watch what birds are doing inside the bird box. This way, you are in complete control of watching birds on the outside as well as on the inside of the bird box. The RBPi even makes it possible to set up a live internet stream if your bird box is in a remote location. You will need the RBPi NoIR camera board and some infrared LEDs. The RBPi site has more details.

RBPi Weather Station

You do not need to rely on forecasts from the radio or television any more. Make your own weather station with the RBPi. This project is very cheap and requires very little energy. Of course, some extra hardware is necessary, but nothing too complicated. For details on the setup, visit DragonTail.

Transmit Morse code

Although this is ancient technology, people dabbling in Amateur Radio still find Morse code very useful. Building an RBPi powered Morse code station will be a very exciting project. With this, you can have device for encoding and decoding Morse code. If you add a vintage Morse key, the authenticity of the project will increase dramatically. For complete details, head over to the RBPi website.

Raspberry Pi gets a stepper-motor hat

Robotics enthusiasts find the credit card sized single board computer, Raspberry Pi or RBPi – a versatile unit for controlling various functions. With several add-ons or HATs readily available in the market, the RBPi can be a formidable force to reckon with. With its latest Motor HAT from Adafruit, your RBPi can control up to four DC motors or two stepper motors using PWM to achieve full speed control.

Although the RBPi has several GPIO pins, not many of them work as PWM. That means, to control motor direction and speed, you require a fully dedicated PWM driver chip onboard. Such chips will handle all the motor and speed controls, while communicating with the RBPi on only two pins – SDA & SCL. These pins follow the I2C standard protocol for communication. Therefore, you can connect this Motor HAT to any other device working with the I2C protocol.

In case you need to control a larger number of motors, as it is often required in robotics, you can easily stack up several of these Motor HAT boards. A total number of 32 boards are allowed by the I2C standard. Therefore, you will be able to control simultaneously 64 stepper motors or 128 DC motors, or a mix of both. To do this, you will have to replace the header on the Motor HAT with a stacking header.

Typically, stepper motor drivers rely on L293D chips. However, the Adafruit Motor HAT uses TB6612 MOSFET drivers. These drivers have the flyback diodes built-in and provide a huge improvement over the L293D – you get 1.2A per channel with 3A as peak current capability. The Motor HAT board comes with a small prototyping area and a polarity protection FET on the power pins. Adafruit offers the Motor HAT fully assembled and tested. All that a user has to do is to solder on the included terminal blocks and the 2×20 plain headers. However, stacking headers are not included.

Looking at the specs of the Motor HAT, you will find four H-bridges with thermal shutdown protection and internal kickback protection diodes. The bridges are capable of driving motors operating from 4.5VDC to 13.5VDC. Each board is capable of driving up to four bi-directional DC motors with individual speed selection using 8-bits or 0.5% resolution. Alternately, you can drive up to two stepper motors – unipolar or bipolar. These could be of single coil or double coil type and the driving could be interleaved or micro stepping.

Motors require a good amount of current for producing the required torque. The huge terminal block connectors allow use or 18-26AWG wires for drive and power. External power can come from a 5-12VDC power supply; the two-pin terminal block connector on the board is polarity protected.

Adafruit Motor HAT board is best suited for RBPi models B+ and A+. For using with models A and B, you have to use an extra-tall 2×13 header in place of the 2×20 header supplied. Adafruit supplies the easy-to-use Python library that makes driving motors a breeze with the RBPi wearing the HAT.

Telegram, Raspberry Pi and Remote Control

People from an older generation may still recall the days the postman would land on the doorstep and deliver a slip of paper with some message in it. Those were the days of Telegrams associated with Morse Code, the dots and dashes way of communicating with far-off places. Mobiles and instant messaging services have now replaced that and other such slow modes of communication. As a result, you can always remain in instant contact with people across the globe.

Similar to the WhatsApp messenger service, Telegram is another application that allows you to chat and share documents with your contacts. Telegram surfaced when WhatsApp crashed about a year back. Being a cross-platform messenger app from Berlin, it gained above five million users within 24 hours and more, since Facebook purchased WhatsApp.

Although at first introduction Telegram and WhatsApp seem identical, there are interesting differences. Both require the telephone number of the recipient for sending them a message. In addition, chatting to individual contacts or to groups is possible. Both have a single and double track system for knowing if the recipient has received your message and has read it.

However, unlike WhatsApp, Telegram allows you to send your messages, videos and photos with a self-destruct timer. Once the set time ends, all your shared documents disappear within a ‘secret chat’. This has a huge advantage. Under secret chat, all documents, locations, videos and images remain encrypted end-to-end and only the sender and the recipient can read them; nobody else can read them, not even the staff at Telegram. The timer can be programmed to activate either after two seconds or up to a week.

Using Telegram on the RBPi is fun and you can use the versatile instant messaging service on the same phone number with different devices simultaneously. Apart from simply using the messaging service to exchange messages, it is also possible to make the RBPi take specific actions automatically, based on the message received by it. For example, if the text message sent is say, “photo”, the RBPi responds by taking a snap of the surroundings with its camera and sends the image to the sender. Similarly, if the message says “lamp”, RBPi can turn on a lamp or open a garage door if the message says “open”.

For using Telegram for remote control, it is best to use the RBPi model B or B+ and have the latest version of the Raspbian as the operating system. However, you can also use the pre-installed Raspbian on the 8GB Class 10 Micro SD card available here. Follow the configuration given in this tutorial as a starting point.

RBPi will be intercepting new incoming messages with Lua, a lightweight, fast, powerful and embeddable scripting language application. Lua uses extensible semantics and associative arrays by combining the simple procedural syntax to powerful data description constructs. That means Lua has the capability to understand text and interpret the action to be taken. In fact, Lua uses a lookup file “action.lua”, much as we use a dictionary, to correlate specific text messages received and the actions that RBPi will take. For details of programming, refer to this blog.

What is a dual screen smartphone?

Most of us use smartphones that sport dual features such as two cameras, two flashes and two SIM sockets. Some manufacturers also make phones with two glass layers for encasing the device. However, one manufacturer has literally followed the adage – two heads are better than one – and produced a smartphone with two screens.

The world’s first dual screen phone – YotaPhone 2 – Is a product of the Russian company, YotaPhone. While the primary display measures 5.0 inches and is an AMOLED display of 1080x1920p resolution and a pixel density of 441ppi, there is a second display on the rear panel. This has a dimension of 4.7 inches, a resolution of 960x540p, a pixel density of 235ppi and is an e-ink display.

The e-ink, rear panel display of YotaPhone 2 has a back matte finish that makes it easy to read from the black and white display. Both, the primary front AMOLED display and the secondary rear e-ink display are protected with a highly resilient layer of Corning Gorilla Glass 3.

Since the secondary display is fully touch-sensitive, you can personalize it easily. For example, rig it up to display notifications and it will show all information of your choice. The main advantage of having a secondary display is power savings. Waking up the full-color display just to check on notifications about messages and mails requires a lot of power. Using the secondary display consumes only a fraction of the power required by the main display.

While on the high-resolution front display you can play games and watch movies, the monochrome rear display is more suitable for static functions such as reading e-books. It is easy to operate one screen at a time, since you can lock out the other one. Operating with the monochrome display saves considerable battery power. However, there is one disadvantage with the monochrome display. An imprint of the previous image can still linger on when you have changed to a new one.

The driver behind the YotaPhone 2 is a Qualcomm Snapdragon 800 SoC. This runs on a 2.3GHz quad core Krait 400 CPU and an Adreno 330 GPU. A healthy RAM storage of 2GB is supplemented with a phone memory of 32GB. YotaPhone 2 comes with an 8MP rear camera and a 2MP front-facing camera. Out of the box, the phone runs Android 4.4 and to accommodate the secondary screen functions, YotaPhone provides the necessary firmware tweaks.

A non-removable, 2500mAH battery powers the device. The phone is capable of being wirelessly charged. YotaPhone has, by design, not provided a very large battery as the secondary screen provides power saving benefits. Additionally, the lighter weight of the battery offsets the increase in the weight of the phone because of the presence of two screens. Additional weight would have made the phone inconvenient to carry. As such, the presence of two displays has significantly increased the thickness of the device.

YotaPhone 2 is fitted with a glass fiber body. This is solid enough considering the weight of the phone at 140gms and a thickness of 8.9mm. The soft curvy edges deserve applause.

What is a Broadband Internet Connection?

To access the internet from homes, offices or mobile devices, internet services are necessary. This is offered in mainly four different forms – Digital Subscriber Line or DSL, cable, fiber-optic and satellite. All the above are commonly known as broadband services since they provide high access speeds compared to the old dial-up connection, which is the only non-broadband service. Although this is the cheapest way of connecting to the Internet, most users prefer faster connections such as provided by a broadband Internet connection.

The DSL connection makes use of unutilized telephone wires to provide Internet service. The speed of the connection varies with the distance of the user from the switching station – the speed will be slower the further away the user is.

A local provider of cable TV provides broadband Internet services through cable. Here, there will be several subscribers on a single service, sharing the bandwidth. The speed will vary with the number of users on the service at any specific time – decreasing as the number of connected users goes up. The speed is usually at its lowest at peak times, for example in the late evenings when many people will access the internet after the day’s work is over.

Fiber optics provides the fastest Internet connection and is the latest method. Since it is one of the newest methods, service areas are limited. In addition, laying fiber-optic cables under the ground is a time-taking task. Although the cost is comparable to that of both DSL and cable, the service provided by the fiber-cable is of a much faster connection.

Satellite services are one of the slowest forms of Internet connection and the most expensive. They are also notoriously complicated to set up and use. However, for people living in remote rural areas, a satellite broadband Internet service may be the only means of communication possible.

Broadband Internet services provide several advantages over more conventional means of accessing the Internet. DSL and cable connections are very easy to obtain and connect with the computer. The high speeds enable users to multitask while working on the Internet. For example, it is possible to surf the net while listening to music over the web.

At home as well as in the office, networking of several computers is made easier with a shared broadband connection. Both wireless as well as wired modems are available for this purpose.

Another trend recently introduced is the mobile broadband service. The modem offered is typically in the shape of a USB stick, only larger. It comprises a wireless device and a socket for the SIM card. When connected to the computer and supplied with the username and password, the wireless device searches for and connects to the transmissions of the service provider. Nowadays, with newer devices in the 4G or fourth generation, very high speeds are achievable.

One of the main advantages of broadband services is that it will not keep your phone lines engaged while you are surfing. This was the case with the old dial-up type of Internet service, where the user would not be able to make or receive telephone calls while connected to the Internet.

Two Delightful Robots Using the Raspberry Pi

Two kits are presented here for those trying to build a robot for the first time. The first is the GoPiGo, a complete robot kit from Dexter Industries and the second is TiddlyBot, a simple fun robot with lots of features. Both kits are great for introducing anyone to the exciting world of robotics and doing it in a fun and simple way. Building robots is a great way for learning Science, Technology, Engineering and Math (STEM), including basic robotics and programming.

GoPiGo

Apart from the robot itself, the GoPiGo kit comprises a full Linux computer, the Raspberry Pi or RBPi, USB and camera expansion for less than $100. You can turn GoPiGo into a full-fledged Wi-Fi robot for exploring unreachable corners of a closet. The inclusion of RBPi makes the possibilities endless. You can even control the robot with your mobile or phone over local Wi-Fi network.

GoPiGo has an acrylic robot body and associated hardware or mounting the RBPi and the Pi camera. It has a control board for motors, controls and extra hardware other than the encoders, wheels and motors.

You need only a screwdriver to assemble the kit. The kit comes with its power source in the form of an 8XAA battery pack along with its connector. You can use your desktop to program GoPiGo directly downloading the program wirelessly or via a USB stick.

The use of the Pi camera along with the RBPi increases the potential of GoPiGo many times over. There is a servo camera mount with the kit and it allows the camera to turn a full half-circle. This increases the robot’s potential for dynamic exploration – for details visit here.

TiddlyBot

If you are looking for something a little less complicated, TiddlyBot is sure to help. Under RBPi control, TiddlyBot begins with robot like movements, using a multi-colored light and progressing to line drawing and following. This is great for teaching children how to program robots as well as for simply playing games.

You can program TiddlyBot using any smartphone, tablet or PC with the provided Blocky Interface, out of the box. It has a web interface for remote control. Use TiddlyBot as a squiggly bot and draw programmatically or let it run freestyle. Use several pens with different colors to make modern art. Makers of TiddlyBot run many workshops for enabling young people pick up nuances of robot building and programming.

What can you do with these two simple but exciting robots? For starters, here are some suggestions:

• Use Wi-Fi To remotely explore a house or office
• Deliver drinks remotely
• Make sneak attacks on unsuspecting people
• Use it for herding pets and babies
• Use it for remote monitoring an event
The greatest benefit of both the robot kits is the inclusion of the Pi camera, which gives the robots their vision. You can monitor where they are going and manoeuver them remotely. This opens up possibilities of several awesome projects. You can make your robots follow hand motions, navigate and map rooms, track objects, follow faces, check on pets remotely, find lost stuff under the couch and so much more – the possibilities are endless.

How Does Wireless Broadband Work?

High-speed Internet access is a necessity nowadays, and people are not satisfied with the slow dial-up access. Different forms of broadband Internet services are available that provide high-speed access. Access speed is usually measured by bit rate, which is the number of bits processed per unit of time. You are using a broadband Internet service if your data speed is or above 256 kbps (kilobits per second). Typical speed figures for broadband downloads can range from 1.5Mbps to 159Gbps. Therefore, broadband is an evolution over the original high-speed internet service, ISDN or Integrated Services Digital Network.

With the proliferation of mobile devices, there is increasing need for mobile broadband services that do not restrict movement with cables and telephone lines. This requirement has brought forth another contender – the wireless broadband Internet service. As its name suggests, you have high-speed access to the Internet without any cable or wires trailing your device. Consumers are increasingly demanding wireless Internet service, as they perceive its versatility and its potential for improving their productivity.

Wireless broadband service is available increasingly at home, in offices and even at the local groceries or coffee shop. Service providers are offering packaged Internet service deals that users can access wirelessly from any location within the coverage area of the service.

You generally connect to a wireless broadband Internet service through a wireless network. Setting up this arrangement of a broadband wireless network in your home or office requires several pieces of equipment – a wireless transceiver and a wireless router – all a one-time expenditure. In addition, you need to invest in a continual expenditure in the form of a broadband service. Without this broadband service, your broadband tools will not work.

The wireless devices and the broadband internet service together make up your wireless broadband network. When deployed, the network will transmit data from your broadband Internet connection via these wireless tools using a special wireless technology called Wi-Fi. Only Wi-Fi enabled devices will be able to connect to the Internet from anywhere inside the coverage area defined by the location of your wireless router.

Although Wireless broadband Internet service is popular and is increasingly being used in homes and offices, there is another wireless technology gaining ground – Wireless Internet service. With wireless broadband Internet service, you have a package deal that involves the broadband service that you have to subscribe to and the hardware for the wireless technology. On the other hand, wireless Internet service is intended for use in a much larger location outside the home or office, such as a college campus or the downtown area of a city.

The growth of cell phones has increased the popularity of wireless Internet connectivity. Cell phones now feature several mobile applications designed with advanced wireless technology. Therefore, mobile devices can now connect to a wireless broadband internet service via Wi-Fi or directly to the Internet via their own cellular phone networks.

GSM or Global Systems Mobile has introduced a technology for improving mobile connectivity – EDGE. Likewise, their competitor CDMA has introduced EVDO, which is significantly faster than EDGE. Another upcoming technology in this field is the WiMAX, which is expected to provide speeds in excess of 40Mbps by the end of next year.

How does fiber-optic broadband work?

Fiber-optic broadband is a high-speed form of connecting to the Internet and works by sending and receiving signals over an optical fiber cable. Unlike the majority of broadband connections in the world that use mobile networks or the telephone lines, fiber-optic broadband transfers signals via special cables under the ground. These signals use light and optical fiber as against copper cables and move a lot faster offering speeds as high as 1Gbps.

Laying optical fibers under the ground is an expensive and time-consuming process. If you are in an area that is served by optical fibers, you can sign up for this superfast fiber-optic broadband service. Even the cheapest fiber-optic connection will provide speeds well in excess of any standard ADSL broadband service. Cheaper services often combine fiber along with copper wires to deliver the connection to your doorstep and are known as FTTC or fiber to the cabinet broadband. This type of connection usually has the fiber-optic line running from the provider to the junction box just outside your house. From here, normal copper wires carry the signal inside your home.

A better type is the FTTH or fiber to the home connection. This will have the fiber-optic cable run all the way inside your home. FTTH is better as it provides speeds up to 300Mbps as compared with speeds of about 75Mbps for the fiber to the cabinet service. However, FTTH services are not so widely available yet.

What can you do if you have a high-speed Internet connection? For example, with only a 50Mbps connection, you could download a 10GB Blue Ray movie in just under a half-hour or download an album of the size of 100MB within 15 seconds. FTTH provides several additional options such as to receive cable TV, phone lines and other excellent bundles with packages offered by service providers. The extremely high speeds offered by fiber optics has made it the backbone for much of the Internet deployed. In the US, the latest deployments are from Google Fiber and Verizon FiOS.

Fiber optics provides several benefits such as faster speeds over much longer distances as compared to the traditional copper-based technologies such as DSL and cable. Although the actual service you get depends on the company providing the service, but in most cases fiber will give you the best bang for the buck. In addition, fiber optics is future-proof as well. Even if broadband speeds increase by 1000 times in the near future, the existing single fiber-optic connection will easily support it.

Technically, fiber optics uses light in place of electricity for transmitting data. That means, much higher frequencies are used and the data capacity is enormous. The fiber-optic cable itself is made of glass or plastic and therefore, immune to electromagnetic interferences unlike metal cables are. Therefore, more data can be transferred to greater distances without any degradation.

Energy loss and interference are the limiting factors for most type of communication transmission, but fiber optics handles these factors in a much better way than any other modes of transmission. However, the biggest limiting factor that is currently hindering the widespread adoption of fiber optics for Internet access is the cost requirements of replacing DSL and cable networks.

Balance your robot with a Raspberry Pi

You may have seen the amazing two-wheel scooter, the Segway Human Transport system. It has only two wheels, a platform for a person to stand and a handle to guide the vehicle. The scooter operates on batteries located under the platform and between the wheels. Dean Kamen is the inventor of this amazing transporter, which can carry a person around while balancing on its two wheels without toppling over.

After watching the amazing Segway scooter, Mark Williams tried his hand at balancing a two-wheeled robot using the tiny credit card single board computer, the Raspberry Pi or RBPi. You can watch his success in the video clip here – it is almost like watching a human baby learn to take its first tottering steps.

Mark’s PiBBOT, or Pi Balancing roBOT, carries its own power source and the electronics, but unlike the Segway, does not have room for a passenger. The TFT displays the angles from the accelerometer, the gyro, the complimentary filter and the power drawn by the motors. There are two buttons on the top – one for turning on/off the motors and the other for resetting the gyro.

The PiBBOT uses the concept of an inverted pendulum to work. This is similar to how children balance a vertical stick on a finger on their outstretched hand – they move in the direction the stick is about to fall, thus attempting to keep its center of gravity below it. The balancing robot keeps itself vertical by using a control algorithm called PID or Proportional Integral Derivative. It does this by trying to keep the wheels under its center of gravity. Therefore, if the robot leans forward, the wheels carry the robot forward, trying to correct the lean. As the bottom of the robot moves forward, inertia keeps its top in the same place, thus righting it.

PiBBOT has an accelerator and a gyroscope to measure the angle of its lean. One axis of the accelerometer measures the current angle, while one axis of the gyroscope measures the rate of rotation. A well-timed software loop running in the RBPi keeps track of both. The RBPi makes calculations based on the measurements to provide power to the motors via the PWM. The RBPi must move the motors in the right direction to keep the robot upright.

Accurate angle measurements need readings from both the accelerometer and the gyro, which are then combined. Individual readings do not provide the necessary accuracy. The gyro measures the rate of rotation and requires to be tracked over time for calculating the current angle. The tracking usually includes noise, which causes the gyro to drift. However, gyros are useful for measuring quick changes in movement.

Unlike a gyro, accelerometers do not need tracking and they can sense both static positions as well as sudden movements – with gravity defining the static position of the robot. However, accelerometers are notorious for their noise levels. Both gyro and accelerometers perform well over certain sensitivity levels.

Mark is using a measurement range of 250dps with a sensitivity of 0.0875 dps/LSB for his gyro. For his accelerometer, he is using 8g full-scale, corresponding to 4mg/LSB and a full scale of 10. Read the full details here.