Category Archives: Sensors

Raspberry Pi Zero for a Real-Time Sensor Dashboard

Using the Raspberry Pi or RBPi, the single board computer (SBC), and a few applications from Google, you can have a functional dashboard showing real-time parameters from sensors. Google offers its App Engine in the form of a Platform as a Service or PaaS. The advantage is you can deploy and run your own applications using the Google infrastructure without bothering about exclusive ways of setting up hardware, servers, or Operating Systems.

Google also offers the free and powerful Google Charts that you can use as simple charting tools for plotting the data from the sensors into line charts. An HTML5 templates generator such as the Initializr is also useful for generating templates for the dashboard. Initalizr has several useful frontend resources such as Bootstrap and jQuery.

RBPi Zero is the perfect hardware platform to use for this project. This SBC is a full-fledged computer, but smaller than a credit card. It features a single-core CPU running at 1 GHz and 512 MB RAM. Along with a 40-pin GPIO header, the RBPi Zero has USB and a mini HDMI port.

When you connect a few sensors to the GPIO pins, the RBPi Zero sends their data over to the Google App Engine. On the dashboard, you can see the values and the charts updating in real-time as new data arrives from the sensors. Github carries the instructions for building and deploying the project for the RBPi Zero app and the App Engine dashboard.

For this project, Java is the programming language, as both the RBPi Zero and the Google App Engine support it – both use the Pi4J library. However, those who prefer Python can easily change the code, as both RBPi and the Google App Engine support Python as well. As the latest version of Raspbian, the Operating System of the RBPi comes pre-installed with Oracle Java 8, it is easy to deploy and run an executable JAR on the RBPi Zero.

The JAR acts as the go-between with the sensors and the Google App Engine – it reads inputs from the sensors and passes them on to the Google App Engine. You can use the Apache Maven to compile and build the code on the RBPi Zero. Of course, you may also build the code on your laptop or desktop and copy the resulting JAR over to the RBPi Zero.

You can use Cloud Endpoint on the Google App Engine side. This is a powerful service for creating a backend API by using annotations. This includes the client libraries for web and mobiles. It generates a Java based Android client for use with the RBPi Zero application. Google Qauth 2.0 authenticates the API for installed applications.

The RBPi Zero based hardware provides readings from three sensors – voltage generated by a solar cell, temperature from an analog temperature sensor, and illuminance or LUX from a photocell. A 10-bit Analog to Digital converter with SPI interface is necessary to covert the analog signal to a digital format suitable for the RBPi Zero. All the sensors work with a supply of 3.3V, and the RBPi Zero is capable of sourcing this.

The Latest Ultra-sensitive Gas Sensors

By using Graphene doped with Boron, scientists have developed ultra-sensitive gas sensors that could one day be able to detect the presence of one molecule of gas in a thousand trillion molecules of air.

Various gases, such as those produced by explosives, are specifically difficult to detect – you need extra-sensitive sensors. However, scientists are considering Graphene as being the new material for creating a stream of electronic devices, including sensitive gas detectors. Graphene has high conductivity and is useful as a gas detector as a one-atom thick, two-dimensional material.

In the Pennsylvania State University, a team of international researchers has created an amalgam from Graphene and Boron. This amalgam has the property to detect particular gases down to the level of mere parts per billion. The team is confident of ultimately making detectors sensitive enough to detect exceedingly tiny amounts of gas in the order of parts per quadrillion.

Scientists have paired Boron atoms with Graphene and created a heteroatom structure. Here, non-carbon atoms bond with carbon atoms to form part of a molecular ring. The structure acts as a sensitive sensor to detect exceptionally low concentrations of gas molecules. It can detect parts per million of Ammonia and parts per billion of Nitrogen Oxide. According to the scientists, this is equal to an ammonia detection rate of 105 times and Nitrogen Oxide sensitivity of 27 times more than what the untreated Graphene can detect.

Mauricio Terrones, a professor of physics, chemistry and materials science at the Pennsylvania State University, says they have been pursuing the project for the past four years. Although they had doped Graphene with atoms of Nitrogen earlier, doping with Boron proved much more challenging. However, once they sorted out that difficulty, they were able to synthesize the boron graphene, collaborations with experts in the US and other countries in the world confirmed their research and the properties of the material.

Graphene is essentially Carbon, while Boron is an element sitting right next to Carbon on the periodic table. That means they have similar atomic structures and therefore, should combine relatively well. However, compounds of Boron are not stable with exposed to air – they break down rapidly – making it difficult to combine the two elements when using normal Graphene production methods.

Researchers overcame this by using a special technique called chemical vapor deposition assisted with a bubbler. This method isolates the atmospheric boron when incorporating the element with the Graphene. The process produces sheets of Boron-doped Graphene of size equal to one-square centimeter.

They then transferred the sheets to the Honda Research Institute USA in Columbia, OH. Here, they compared the performance of the sheets with the performance of known highly sensitive gas sensors. Scientists at the Novoselov lab at the University of Manchester, UK examined the electron transport function of the sensors. Simultaneously, contributing researchers in Belgium and the US established the meld of Boron atoms within the Graphite lattice and studied the influence of their interaction and influence with Nitrogen Oxide or Ammonia.

According to Dr. Avetik Harutyunyan, the Chief Scientist and project leader at the Honda Research Institute USA Inc., this multidisciplinary research offers new avenues for further exploring ultrasensitive gas sensors.

How do Sensors Measure Gear Tooth Speed and Direction?

Measuring speed of gears is an important factor in various industries, especially in pharmaceutical, tobacco, printing, woodworking, paper, textile, food and others where rotational machinery predominates. Gear speed measurements also necessary in pumps, blowers, mixers, exhaust and ventilation fans, wheel-slip measurement on autos and locomotives, flow measurement on turbine meters and many more.

The most common gear tooth sensors detect a change in the magnetic field for determining the speed and direction. Usually, these are of three types – the Hall Effect, magneto-resistive and the Variable Reluctance. There are optical types of sensors as well, detecting a change in light levels as the gear rotates past the sensor.

Sensors using magnetic properties are good for measuring speed and direction of gears made of ferrous metals. All these sensors are non-contact type and sensitive to detect the presence of gear teeth passing in front of the sensor. As a gear tooth comes close to the magnetic sensor, its output flips and the electrical level at its output changes state. The output remains steady as long as the gear tooth is within the detectors sensing zone. As the tooth passes out of this zone, the output flips back. Therefore, a magnetic sensor placed in front of a rotating gear, the output from the sensor will be a series of electrical pulses.

There are several advantages when using magnetic sensors. Apart from the sensors being non-contact type, they are robust, hermetically sealed and can withstand unregulated power supply. Most manufacturers make then RoHS and IP67 compliant. That means no lead or other toxic materials are used for manufacturing these sensors and dust or liquid will not enter their enclosure. That makes such sensors suitable for use in food processing industries.

For measuring the speed of gears made of non-magnetic material, engineers often use optical sensors. The most common sensor of this type is the optical interrupters. Gear teeth interrupt a light beam from an LED source and the detector produces a corresponding electrical output. A continuously rotating gear in front of the sensor therefore, creates a similar series of electrical pulses as the output from magnetic sensors do.

The functioning of optical speed or proximity sensors is dependent of the dust and dirt level of the environment where they are used. Therefore, their range of applications is somewhat restricted as compared to magnetic sensors.

Measurement of direction involves a reference point, which means two sensors need to be used, with one of them being the reference sensor. An electronic circuit measures the time gap between the responses from each sensor. As the gear tooth passes in front of both sensors, one of them will change output before the other. If sensor A happens to trigger before sensor B does, the electronic circuit determines the gear is moving from A towards B. In case the output of sensor B switches before sensor A does, then the gear is moving from B towards A.

Usually, the sensors provide separate digital outputs for speed and direction. Their measuring capability may extend from detecting near zero speed up y 15 kHz.

How do Sensors Measure Angle?

An angle is the degree of rotation of an object from a reference position about a central axis. In the engineering world, there are two types of angles requiring measurement. One is the physical or mechanical characteristic, such as the rotation of a shaft with respect to its bearing or housing. The other is a mathematical term such as the angle between two phases of alternating voltage system. Usually, sensors measure angles in a format that a computer or a machine can understand, interpret and utilize.

It is also a common practice to convert a physical characteristic into a rotational mechanical movement to measure linear displacement. For example, the distance traveled by a shaft can be translated into rotational movement by a rack and pinion arrangement. The angular position sensor attached to the arrangement then interprets the angular movement in proportion to the linear movement of the shaft.

In the market, you will find different sizes and forms of angle positioning sensors using various technologies. Generally speaking, these sensors are versatile and one can use them in all kinds of applications, such as in agriculture, commercial equipment, off-road vehicles and in automotive industries. Most of the applications above require a product suitable for operating in harsh environments, including moisture, dirt, dust, extreme temperatures and more.

For example, Forklift Position sensors measure the angle of the forks on a forklift truck. According to OSHA, one of the primary causes for tip-over accidents on forklifts is excessive speed when the machine is turning or rounding a corner. The angle position sensor on the truck helps it to remain within a safe speed and prevents overturning. This particular application also prevents accidents from unbalanced loads and limits the operation of the machine when the load is improperly positioned or balanced.

The simplest form of measuring angle is by using the gear tooth sensor. By sensing the teeth to count the rotation of a gear or wheel, engineers monitor and limit speed. Another common form of angular position measurement utilizes potentiometers. Other more sensitive and rugged types of angle sensors use optical or magnetic technology.

Traditional rotary encoders use an LED transmitter, a coded disc and a photo sensor to detect angular movement. The disc is coded with opaque and transparent sections, which transmit light in a specific manner to the photo sensors depending on the position of the disc. The photo sensor converts the light falling on to it into an electrical code. This allows the encoder to detect rotation, position, angle, etc.

Sensors that are more rugged use the Hall-Effect technology for measuring angle. This technology uses magnetic field sensing and does not require the critical positioning necessary for the components using optical methods. In both methods, accuracy of an angle sensor depends largely on its resolution. The higher the resolution, the more precise is the detection of angular movement. Sensors measuring angles using Hall-Effect technology can perform without physical contact, thereby remaining unaffected by vibration and abrupt movements. These sensors also have the added benefits of virtually unlimited lifespan.

How do AC Current Sensors Work?

You can sense current using a series resistor and measuring the voltage drop across it. According to Ohm’s law, the current through the resistor is then the voltage drop divided by the resistance value. That makes the voltage drop proportional to the value of the resistance and the current flowing through it. The disadvantage is obvious – to prevent the voltage drop from affecting the circuit parameters, one needs a very low value resistor when the current involved is high. Additionally, as the current reduces, so does the voltage drop. That involves amplification of the voltage drop, creating additional circuit complexity.

Ideally, current sensors should not use any power when detecting the current in the circuit. However, real current sensors do require a part of the energy from the circuit for providing the information. For sensing AC currents, current sense transformers are typically useful. A single wire from the circuit acts as the primary of the transformer or the primary may be a single turn winding on the transformer.

The AC current sense transformer develops a current in the secondary, proportional to the sensed primary current. The secondary current is allowed to flow through the terminating resistor to produce an output voltage. As the turns ratio of the transformer decides the secondary current, a low turns ratio (pri/sec << 1) minimizes the current through the terminating resistor. A balance of the transformer ratio and low-enough current through the terminating resistor ensures adequate output voltage. You select the appropriate AC current sensor based on the frequency range and current rating of the sensor for the conditions of your application. The highest flux density to prevent saturation of the sensor core will then depend on the worst-case current and frequency conditions in the circuit. The requirement is to generate a voltage output from the sensor that will vary linearly with the current being sensed. If the core saturates, the output becomes non-linear, and the output voltage is no longer strictly a representative of the input current. Sensors come in surface mount or through hole types, with different turns ration and overall dimensions. As noted earlier, you can have a sensor only type, which has a conductor integral to the application serving as the primary. The other is a current transformer type, where the primary is an included winding. Current transformer manufacturers offer online selection tools for selecting the right current sensor for the specific application. Initially, the user selects either an SMT sensor or a leaded type of sensor. The tool then requires the user to input the maximum sensed current expected, the input frequency, the duty cycle of the primary current waveform and the desired output voltage. The output voltage being the desired output voltage for the maximum input current the user expects. Based on the maximum input current, the number of secondary turns and the output voltage necessary, the tool suggests the required terminating resistor value. For this calculation, the tool assumes a single-turn primary. The tool also provides the maximum flux density based on the above parameters and the maximum operating frequency, making sure the value does not exceed 2K Gauss to ensure linearity.

ARDUINO 101: The Curie-Powered Sensor-Packed Arduino

Intel and Arduino have teamed up to generate a new single board computer, the Arduino 101. Scheduled for market availability in the first quarter of 2016, the Arduino 101 is powered by the Curie module from Intel. Aimed at educating youngsters in the emerging technologies, the SBC is packed with sensors, yet affordably priced.

Arduino 101 has the input and output capabilities of the classic Arduino UNO, but also includes hardware for Bluetooth wireless communication. In addition, Arduino 101 comes with a gyroscope and a 6-axis accelerometer.

Intel and Arduino are promoting their cobranded board for furthering their initiative, Arduino 101 in the Classroom. This is a computer science and design curriculum meant for educating students in the age group 11-14 years in emerging technologies. The Arduino 101 will also be following the hardware configuration of the Curie module. Contestants will be using this board during the upcoming reality television show, America’s Greatest Makers, by the Intel and Turner Broadcasting System.

Those familiar with the Arduino UNO will find Arduino 101 has the same form factor of 70x55x20mm. Differences are an on-board antenna on the bottom right-hand corner of the circuit board and a new main processor. This is the Intel Quark, a low-power 32-bit micro-controller also known as the Curie module. The specialty of this particular Quark is the Bluetooth communication hardware, the gyroscope and the 6-axis accelerometer are on its die.

Users can program the Arduino 101 in the same process they followed for the Arduino UNO. You write your code and compile it with the Arduino IDE, before uploading it to your board. To allow programmers utilize the unique features of the Curie module, Intel is expected to offer special libraries. Initially, Intel had packaged the Curie module in the size of a tiny button and it was supposedly meant for wearable projects. Later, they changed direction towards the Curie-powered Arduino.

Intel is following this go-to-market strategy for its system-on-chips. Intel also packaged an earlier SOC, the Edison. Intel also designed accessory boards for the Edison and Sparkfun produced these boards for Intel. Intel and Arduino had teamed up earlier for the Intel Galileo – the micro-controller board certified by Arduino had Arduino-compatible headers.

The specifications of the Curie indicate it is powered by 1.8V, the popular voltage of a coin-cell battery. However, to power the IO on the Arduino 101 properly, the voltage requirements as dictated by the Arduino ecosystem are at least 3.3V. Limitations imposed by the Arduino 101 design rule out the possibility of a coin-cell battery powering the Curie.

The Curie module also has a 128-node neural network built into it, which users could use for machine-learning applications. However, Intel will not be providing software support for the technology at the time of Arduino 101 launch. They may support it later.

David Cuartielles, the co-founder of Intel’s marketing of Arduino, will be using Arduino 101 in their Creative Technologies in the Classroom or CTC. Earlier, the curriculum used the Arduino UNO for teaching students in a playful way. Now, they will be using the Arduino 101 for teaching basic programming skills in electronics and mechanical design.

Infrared Thermopile Sensor for the Raspberry Pi

The usual process for measuring temperature is to place the probe directly touching the surface whose temperature is to be measured. That assumes the sensor is placed on the tip of the probe and must be in contact with the surface of interest. However, heat is a radiation and as infrared rays emanating from the surface carry information about how hot the surface really is, it should be possible to measure temperature remotely. Texas Instrument has designed a contact-less infrared thermopile sensor, the TMP006, and Adafruit is offering this on a breakout board suitable for the popular single board computer, the RBPi or Raspberry Pi.

Therefore, using this Infrared Thermopile Sensor with the RBPi, you can measure temperature of an object without touching it. The TMP006 is an embedded thermopile sensor that absorbs Infrared radiation emitted by a surface towards which you point it. It generates a small voltage proportional to the radiation falling on it, which the RBPi substitutes in a polynomial equation. The RBPi solves the equation, thereby converting the voltage into degrees, either Centigrade or Fahrenheit, as the user requires. TMP006 is capable of measuring over an area, so it is handy for determining the average temperature of an object.

As the TMP006 sensor comes in an ultra-small package, a BGA with 0.5mm pitch, it is impossible to solder manually. That is why Adafruit is offering this sensor already soldered on an easy to use breakout board. As the sensor works with three or 5V logic, no logic shifting is necessary to interface it with the RBPi. The sensor IC has two address pins and works with the I2C protocol. Therefore, you can hook up eight such TMP006 sensors to the RBPi, should you need to expand on the measurement. The Adafruit board has a 0.1” breakaway header to allow easy soldering, making it easy for using the sensor on a breadboard. The board also has two mounting holes for attaching it to an enclosure.

Users must note that TMP006 works by measuring the emissivity of an object. The sensor is suitable for measuring the temperature of a surface that has an emissivity greater than 0.7. The surfaces of most polished and shiny metal objects have an emissivity value too low for use with the TMP006. However, for measuring the temperature of surfaces with low emissivity, you can paint it with lampblack paint, which has an emissivity of 0.96.

The TMP006 accurately detects signals in almost the entire field of view of the sensor. For calculation of the final temperature, the sensor integrates all the signals present in the field of view. Therefore, more the signal that the IR sensor can capture from the target better is the accuracy of its measurement.

The percentage of signal absorbed by the IR sensor depends on the angle of incidence of the signal with respect to the sensor. Therefore, for best results, you must place the TMP006 directly underneath the target object. This will make the surface of the target parallel to the TMP006, and the angle of incidence between them will then be zero degrees, allowing the sensor to capture the maximum amount of signal.

Researchers Create a Highly Sensitive Magnetic Sensor

Scientists at the National University of Singapore have constructed a new hybrid type of magnetic sensor that is more responsive that the existing varieties. This innovation holds promise for the creation of cheap and compact sensors and detectors in areas like information technology, electronics, health sciences and automotive industry.

Professor Yang Hyunsoo, who has directed the design of the device, has explained the findings in the September 2015 issue of the periodical Nature Communications.

Using the concept of magneto resistance

Just as electric resistance develops when an electric current passes through a conductor, a similar feature called magneto resistance comes into being when certain substances are placed in a magnetic field. Scientists at the university have utilized this newly discovered feature in developing the magnetic field sensor.

Although the feature is exhibited by all magnetic materials, the university team has been on the lookout for an ideal material, which would be particularly receptive to low and high fields, while remaining immune to temperature variations. In other words, the magneto resistance should vary appreciably with any change in the magnetic field but should be stable when the temperature changes.

Graphene and boron nitride combination

The scientists tried out several groupings of different materials. These trials led to a hybrid arrangement comprising graphene and boron nitride that suggests great potential as a sensing device. The team experimented with the material placed at various angles with the field and at different temperatures. According to Dr. Kalon Gopinadhan of the university, a two-layer structure of the two materials shows a sizeable response to small changes in magnetic fields. The researchers found that the hybrid structure was 200 times more receptive than sensors currently in use.

A significant gain of using this sensor is that the combination shows very high sensitivity at and around 127 degree Celsius, the temperature at which most electronics function. The sensor is small and can be easily fitted into other devices. Furthermore, the manufacturing cost of graphene is very low as compared to that for existing sensors made from indium antimonide.

Complying with industry requirements

The demand for reliable magneto resistance is expected to rise steadily. Indium antimonide sensors used in the automotive industry suffer a change in properties due to temperature changes caused by the air conditioning or the sun’s heat and do not function reliably. Cars and other vehicles use several sensor systems in interlocks, flow meters and position sensors that make use of complicated temperature correction circuitry to offset the errors. The new hybrid sensor eliminates the necessity of these rectification procedures.

Professor Yang declares that the graphene and boron nitride combination is prepared to take on the current sensors in the market. Apart from finding use in applications like hard drives, thermal switches and magnetic field detectors, they can be incorporated in flexible electronics, as well.

The university team has applied for a patent for the innovation. They now plan to scale up their production in order to turn out wafers of several sizes to meet the demands of the sensor industry.

Get 37 Sensors for Your Raspberry Pi

If you have a bunch of school kids rearing to have a go at the most popular single board computer, the Raspberry Pi or RBPi, then this 37-sensor kit is something that can keep them happy for hours on end. Fans of the open source RBPi will relish the different kinds of experiments they can try out with the funny and completed modules in this new kit.

The modules in the kit connect to your RBPi and send it all kinds of different signals from the physical world. Using these modules by connecting them to the RBPi is very simple as the manufacturer of the kit provides detailed information and usage guidelines for all the sensors in the kit.

The latest kit from SunFounder comes with the sensors neatly packed in a plastic box, along with the 168-page user manual. The improved Fritzing breadboard and the sensors are suitable for the RBPi Model B+ and RBPi2. The kit also contains the detailed material list of each module. Users get the improved code in Python and C along with the Fritzing images. That certainly helps the user to learn to use the sensors for their individual applications.

You must have your own RBPi for using the sensors in this kit, as the kit itself does not come with the RBPi. Moreover, the 40-pin GPIO expansion board included with the kit is for the RBPi B+. The most interesting part of the kit is the 16×2 LCD module and the Breadboard. Using these and the several sensors you can try out about 35 experiments listed in the kit.

The experiments cover a mixture of analog and digital electronics. For example, you can learn about how a relay works, how a mercury tilt-switch functions or how to make an active or a passive buzzer sound the alarm. Those interested in remote sensing will find the Hall sensor fascinating, along with the sound sensor and the gas sensor. With the Ultrasonic Ranging Module, you can easily measure distances without approaching the distant object.

For those interested in temperature measurements, there is the DS18820 Temperature Sensor and the Thermistor module. The RTC-DS1302 module will help in measuring in real time, while the Barometric-BMP180 and the Humidity sensor will help in determining or predicting the weather.

Experiments in light interest many. For them, the kit includes dual color LEDs, RGB LEDs, and Auto-Flash LED modules. Photo-interrupter modules, IR obstacle modules, IR remote control module and the IR receiver modules will help those interested in communication with light beams.

Control experiments that are more sophisticated are also possible. For example, those interested in Analog to Digital and Digital to Analog conversion and control will find the AD/DA Converter PCF8591 module to be useful. Other modules such as the Rotary Encoder module, the Joystick PS2 module, the MPU6050 module hold promises of still further sophistication.

The kit is suitable for all types of beginners, learners and the more initiated. It is an attempt to allow users to learn the basics of analog and digital electronics. Users can then move over to experimenting with different types of sensors and learn about controlling their physical world.

How Gesture Sensors are Revolutionizing User Interface

Imagine a scenario where you control almost everything by simply waving your arms and not by punch any buttons or touching a screen. Welcome to the complicated world of gesture controls. Mechanical buttons and switches are subject to the risk of reliability – they also need protection from the environment. When replaced with electrical controls, such as resistive or capacitive displays and buttons, these do bypass the problems faced by mechanical switches. However, to operate, they still need the physical touch of the operator.

By using optical sensors, it is easy to avoid the reliability risk, mechanical complexity and the requirement for physical touch. You can find optical sensors being used as proximity detectors in many applications such as in water and soap dispensers. Apart from the ease of operation, optical sensors provide the primary potential in recognizing user gestures, thereby reducing system complexity and enhancing user functionality. Today, gesture sensors have evolved to revolutionize user interface controls. They offer the ideal combination of functionality, performance and ease of implementation.

For instance, gesture sensor TMG3992 and others offer simple digital interfaces and do not demand significant processing or memory bandwidth to operate. Being interrupt driven, such sensors interact with the system only when they encounter a recognized event. Simple electrical and software designs are enough to implement two and four direction gesture sensing applications. The sensors work easily from behind plastic or glass transparent to infrared light. That means there is no added complexity or reliability risk in incorporating gesture sensors in electronic devices, as most use plastic housings transparent to infrared.

Gesture sensors help the industry in myriad ways. For example, heavy industries use gloves that limit options for user interface. Operators need specialty gloves to operate most capacitive touchscreens, as they do not respond to commonly used gloves. On the other hand, there are no restrictions for gesture sensors to operate with any type of gloves.

Gesture sensors are eminently suitable for recreational applications such as cold weather or aerial sports and industrial applications such as clean room manufacturing, chemical industries and construction. For example, a skier may keep his or her hands warm within gloves and yet operate a smartphone or manipulate a self-mounted camera with ease.

Touchscreens do not work in environments under water. However, divers can make full use of gesture sensors. It is true water attenuates infrared light and restricts the working distance, so you need additional power. However, multiple benefits overcome this minor restriction. Using gesture sensors such as the TMG3992 and similar greatly simplifies the user interface as underwater cameras can do the job, while the TMG3992 replaces several mechanical buttons and switches for a smaller and more reliable interface.

Smartphone designers and manufacturers already include several user interface options offering multiple solutions for different tasks. However, in many situations – such as exercising or cooking – it is inconvenient to touch the phone while performing the tasks. Gesture controls provide the user different ways of interacting with the phone – such as when checking notifications and scrolling through them. For example, the user can identify a caller and select from a variety of options – answer the call with the speaker enabled, ignore the call without a response or ignore the call with a pre-defined text message.