Videocon launches dual-SIM A20 and A30 Android smartphones

 Videocon launches dual-SIM A20 and A30 Android smartphones


After launching budget feature phones earlier this year, Videocon has now forayed into the budget Android market with two new smartphones, the A20 and A30. The A20 is priced at Rs. 4,999 while the A30 costs Rs. 7,299.

The A20 runs on Android 2.3 and sports a 3.5-inch HVGA display and features a 3-megapixel rear camera and a VGA front-facing camera. It is powered by a 1GHz Qualcomm Snapdragon processor underneath with 256MB RAM. It comes with a 1350mAh battery. The smartphone has 512MB of on-board storage with external expansion options upto 32GB via microSD card.

The A30 on the other hand comes with beefed up specs in comparison to the A20. The device runs on Android 4.0 and has a 4-inch WVGA display, a 5-megapixel auto-focus rear camera with LED flash and a VGA front-facing camera. Under the hood, it features a 1GHz dual-core Qualcomm Snapdragon processor with 512MB RAM and comes with 4GB internal storage (expandable upto 32GB). It has a 1500mAh battery.

Connectivity options on these dual-SIM smartphones include 3G (HSDPA 7.2Mbps), Wi-Fi 802.11 b/g/n and Bluetooth 3.0. Both devices also come with various pre-installed apps including Facebook, History Eraser and more.

Current mobile offerings from Videocon in the feature phone segment include V1528, V1531+, V1542, V1544, V1548 and V1580 ranging from Rs. 1,799 to Rs. 2,999.

Videocon A20 Specifications

• 3.5-inch (480×320 pixels) capacitive touch screen display
• Dual SIM (GSM + GSM) with dual standby
• 1 GHz Qualcomm Snapdragon processor
• 256MB RAM
• 3-megapixel rear camera
• VGA front-facing camera
• 3G (HSDPA 7.2Mbps), Wi-Fi 802.11 b/g/n, Bluetooth with A2DP and GPS
• FM Radio with Recording
• 512MB internal storage expandable memory up to 16GB with micro SD
• 1350 mAh battery
• Android 2.3

Videocon A30 Specifications

• 4-inch (800×480 pixels) capacitive touch screen display
• Dual SIM (GSM + GSM) with dual standby
• 1 GHz dual-core Qualcomm Snapdragon processor
• 512MB RAM
• 4GB internal storage expandable memory up to 32 GB with micro SD
• 5-megapixel auto-focus camera with LED flash
• VGA front-facing camera
• 3G (HSDPA 7.2Mbps), Wi-Fi 802.11 b/g/n, Bluetooth 3.0 with A2DP and GPS
• FM Radio with Recording
• 1500 mAh battery
• Android 4.0

RIM loses BlackBerry subscribers

RIM loses BlackBerry subscribers for the first time

  

 BlackBerry maker Research In Motion (RIM) has announced that it lost subscribers for the first time in the latest quarter, as the global number of BlackBerry users dipped to 79 million.

Three months ago, RIM had 80 million subscribers. Analysts said the loss of 1 million subscribers was expected. Once coveted symbols of an always-connected lifestyle, BlackBerry phones have lost their luster to Apple's iPhone and phones that run on Google's Android software.

In a rare positive sign, the Canadian company added to its cash position during the quarter as it prepared to launch new smartphones on January 30. The new devices are deemed critical to the company's survival.

Shares of the company were hit last week in after-hours trading after the BlackBerry maker said it plans to change the way it charges fees.

RIM's stock initially jumped more than 8 per cent on Thursday in after-hours trading on the news, but then fell $1.48, or 10.4 per cent, to $12.65 after RIM said on a conference call that it won't generate as much revenue from telecommunications carriers once it releases the new BlackBerry 10 platform.

RIM's stock had been on a three-month rally that has seen the stock more than double from its lowest level since 2003.

RIM is changing the way it charges service fees, putting an important source of revenue at risk.

RIM CEO Thorsten Heins has said only subscribers who want enhanced security will pay fees under the new system.

"Other subscribers who do not utilise such services are expected to generate less or no service revenue," Heins said. "The mix in level of service fees revenue will change going forward and will be under pressure over the next year during this transition."

RIM is banking its future on its much-delayed BlackBerry 10 platform, which is meant to offer the multimedia, Internet browsing and apps experience that customers now demand.

"We believe the company has stabilised and will turn the corner in the next year," Heins said. He noted that the company's cash holdings grew by $600 million in the quarter to $2.9 billion, even after the funding of all its restructuring costs. RIM previously announced 5,000 layoffs this year.

Heins said subscribers in North America showed the largest decline, but said there is growth overseas.

RIM posted net income of $14 million, or 3 cents per share for its fiscal third quarter, which ended December 1. That compares with a profit of $265 million, or 51 cents per share, in the same quarter a year ago.

The latest figure includes a favorable tax settlement. Excluding that adjustment, RIM lost 22 cents per share.

RIM reported revenue of $2.7 billion, down 47 per cent from a year ago.

Huawei Ascend G330 with Android 4.0

• Huawei Ascend G330 with Android 4.0 now available for Rs. 10,990

Initially announced at IFA this year alongside the Ascend G600 and the Ascend Y201 Pro, the Ascend G330 is now available in the country with online retailing portal Snapdeal for Rs. 10,990. Though it is listed on Flipkart as well for Rs. 10,999, the device is currently out of stock.

The Ascend G330 has specs similar to the G300 like a 4-inch (800×480 pixels) IPS capacitive touch screen display and a 5-megapixel auto focus camera with LED Flash. But the Ascend G330 comes with a 1GHz dual-core processor, Android 4.0 and a front-facing camera.

Huawei officially launched the Ascend G300 and the Ascend Y200 in the country back in July  this year priced at Rs. 13490 and Rs. 8,190 respectively.

The Ascend G300 is a mid-range smartphone with specs like 4-inch WVGA display, 512MB RAM, 1GHz dual-core processor, 5-megapixel camera and a 1500mAh battery.

The Ascend Y200 features a 3.5-inch IPS touch screen, Qualcomm 800MHz CPU and Android 2.3. The smartphone also comes with a dual-mic, used for background noise cancellation and a 1250mAh battery.

The company has also partnered with other telecom operators like Spice and Airtel to launch smartphones in the Ascend series in India. It unveiled the Ascend Y100 for Rs. 5,990 in collaboration with Spice and also launched the first 4G smartphone in the country with Airtel namely the Ascend P1 LTE boasting impressive specs such as a 1.5GHz dual-core Qualcomm Snapdragon S4 processor, 1GB RAM, 4GB storage, 4.3-inch Super AMOLED qHD display with Gorilla Glass 2 and 8-megapixel rear camera with dual LED flash.

Huawei Ascend G330 Specifications

• 4-inch ( 800×480 pixels) IPS capactive touch screen display
• 1GHz dual-core Qualcomm Snapdragon MSM8225 processor
• 512MB RAM
• 5-megapixel auto focus camera with LED Flash, VGA front-facing camera
• 3.5mm audio jack, FM Radio
• 3G (HSPA  14.4Mbps, Upload 5.76Mbps), WiFi 802.11 b/g/n, Bluetooth V2.1 + EDR, GPS / aGPS.
• 4GB internal storage (2.4GB user accessible), 32GB expandable memory
• 1500mAh battery
• Android 4.0 

Samsung plans to ship half a billion handsets in 2013

The Korean phone company aims to ship 510 million handsets next year

























According to The Korea Times, the phone manufacturer expects itself to ship over half a billion handsets -- 510 million to be exact -- next year.
In 2012 alone, Samsung shipped an estimated 420 million devices. If we go by next year's projections, it's aiming for a 20 percent jump in devices shipped.
Of the 510 million devices forecast, 390 million units are expected to be smartphones, while the remaining 120 million will be feature phones.
Also in Samsung's plans are more Microsoft Windows 8 handsets, and an executive at Samsung's telecommunications department noted the high user demand for LTE devices.
Despite its ongoing patent battle with Apple, which topped CNET's list of 2012's biggest tech stories, Samsung has managed to be a huge success both in the U.S. and overseas, thanks to its successful Galaxy line of phones, tablets, and even 'phablets.' Do you guys think Samsung has what it takes to fulfill its big projections for next year?

Remote Control for Home Appliances

Using this circuit, you can remotely control the switch-on and switch-off operation of your AC mains operated home appliances. The working range of the circuit depends on the orientation and the intensity of the IR beam.

The circuit consists of a transmitter and a receiver.

 Fig. 1: Transmitter circuit
Fig. 1 shows the transmitter circuit. It is built around timer IC NE555 wired as an astable multivibrator. The multivibrator produces a pulsed output waveform with ‘on’ time of about 57 µs and ‘off’ time of about 326 µs, which means it generates about 2.6 kHz. The output of IC1 is fed to IR LED1 through current-limiting resistor R3. The IR LED1 used here is the same as in TV remotes. The circuit operates off a 9V battery, which is connected to the circuit through switch S1.

Fig. 2 shows the receiver circuit. It consists of phototransistor L14F1 (T1), voltage regulator 7805 (IC2), three 2N2222 transistors (T2, T3 and T4), dual voltage converter LM319 (IC3), dual J-K flip-flop 74109 (IC4) and some discrete components. The circuit operates off a 9V battery, which can be connected to the circuit through switch S2.

The Darlington pair built around transistors T2 and T3 amplifies the photo-current generated by the photo-transistor (T1). The equivalent photo-voltage appears across resistor R4. So across resistor R4 you get a replica (in term of wave shape but not in amplipude) of what you produce at the output of IC1 in the transmitter. The amplitude would vary with distance and other factors such as the angle of arrival of the IR beam at sensor L14F1.

 Fig. 2: Receiver circuit



The low-pass filter constituted by resistor R7 and capacitor C4 produces about 3V DC. This DC voltage is fed to the junction of the inverting input of N1 and the non-inverting input of N2. The window comparator (IC3) is designed such that whenever the input voltage is between 2 and 4 volts (greater than 2V but less than 4V), its output goes high. If the input voltage is less than or equal to 2V, or more than or equal to 4V, the output goes low.

The window output is fed to the clock input of J-K flip-flop CD74109 (IC4). IC4 is wired in toggle mode. That means its output goes high if it is initially low and vice versa every time it is clocked. The output of IC4 is fed to the base of relay-driver transistor T5. Relay RL1 energises to light up the bulb when transistor T5 conducts.

Working of the circuit is simple. Initially, when no IR beam is falling on sensor photo-transistor T1, the DC voltage appearing at the input of the window comparator is nearly zero. The window output remains low. Transistor T5 is cut-off and the relay remains de-energised.

When switch S1 is pressed momentarily, the IR beam falls on the photo-transistor for this short period of time and a postive-going pulse appears at the input of the window comparator. The output of the comparator goes low, which toggles the flip-flop (IC4) and transitor T5 conducts. Relay RL1 energises to switch on bulb B1.

Assemble both the circuits on separate PCBs and house in suitable cabinets. In the transmitter unit, fix IR LED1 on the front side and switch S1 on the back side of the cabinet. Keep the 9V battery inside the cabinet.

Similarly, in the receiver unit, fix the photo-transistor (L14F) on the rear side such that the IR beam falls on it. To avoid circuit malfunction, cover the phototransistor (T1) with a suitable contraption so that the phototransistor is not exposed to unwanted light sources. Fix switch S2 on the front panel and the relay on the back side. Keep the 9V battery inside the cabinet. 

1.5W Power Amplifier

Here we put all the theory to work and present a simple power amplifier module that can be easily built with readily available components. The block diagram of the amplifier is shown in Fig. 1. It is typical of most audio amplifiers, although the circuit is somewhat different.

A power amplifier contains audio input, amplifier, driver, output and power supply sections. The amplifier section provides most of the voltage gain. The driver stage is a buffer between the amplifier section and the output stage. The output stage usually has to drive a low-impedance load such as a loudspeaker. The power comes from the power supply, and the output signal appearing across the load should ideally be a replica of the input signal. In other words, the output stage takes power from a DC supply to boost the signal so it can drive a load.

Fig. 1: Block diagram of 1.5W power amplifierThe circuit shown in Fig. 2 shows the amplifier, driver and output sections. The amplifier section is built around JFET VHF/UHF amplifier 2N5484 (T1) and npn transistor BC548 (T2). The driver section is built around transistor BC639 (T3) while the output section is built around transistors BD139 and BD140 (T4 and T5).

The input signal is coupled to volume control VR1 via capacitor C1. The value of VR1 is specified as 1-mega-ohm. Since the gate terminal of FET (T1) can be regarded as an open circuit, the input impedance of the circuit is equal to the value of VR1. Like all audio volume controls, VR1 needs to have a logarithmic taper (usually denoted as ‘type C’) to give an apparent linear relationship between rotation of the control and the volume level. This is necessary because human hearing follows a logarithmic response, in which a change in the output power by a factor of 10 is heard as a change by a factor of two.

  Fig. 2: 1.5W power amplifier circuit


The FET stage in amplifier section is used to give a high input impedance. The next stage is common-emitter amplifier comprising transistor T2. Preset VR2 is used to adjust amplification and avoid direct coupling between transistor stages T2 through T5. This means that DC voltages for T3, T4 and T5 are all determined by the collector voltage at T2. The most important voltage is at the emitters of T4 and T5. Preset VR2 is used to adjust this to half the supply voltage. To stabilise this and other voltages in the circuit, resistor R13 gives negative feedback from the output to the emitter of transistor T2. If capacitor C8 is not included, the feedback will be for both DC and AC voltages. It will be for DC only if C8 is added.

When voltage at the emitters of transistors T4 and T5 rises, say, due to a temperature change, the voltage at the emitter of transistor T2 will also increase by way of R13. This will cause T2 to conduct less current, making the DC voltage at its collector increase. As a result, transistor T3 will conduct more current and its collector voltage will drop. This then reduces the voltages at the bases of T4 and T5 and hence their emitter voltages.

Driver transistor T3 and its collector load is the base circuitry associated with T4 and T5. In effect, T3 is connected as a common-emitter amplifier. The output signal developed across T3 is applied to the base of T4 via diode D1 and the parallel combination of resistor R9 and preset VR3. The base of pnp transistor T5 connects directly to collector of T3. The driver stage therefore drives a relatively low-resistance load, requiring a transistor capable of handling high power.

The output transistors are npn transistor T4 and pnp transistor T5, connected as a complementary symmetry class-AB output stage. In this configuration, an npn transistor and a pnp transistor (complementary) with equal current gains (symmetrical) are required. Thus, ideally, the DC current gains of T4 and T5 should be matched by measurement.

The DC biasing circuit for T4 and T5 has one diode and two parallel-connected resistors. Preset VR3 is used to adjust the quiescent collector current of T4 and T5 and therefore the class of operation. The output stage also involves capacitor C4, which is known as a bootstrapping capacitor. Bootstrapping is included to allow a higher output voltage swing. If capacitor C4 is not included, biasing resistors R7 and R8 are combined into a single resistor.

Ideally, the output signal should be able to swing from 0V to the value of the supply voltage. However, this cannot happen due to the 0.6V forward bias required across the base-emitter junctions of the output transistors and also the losses. For the positive half cycle, if the output is to reach the supply voltage, the voltage at T4 must be at least 0.6V higher than the supply voltage. Similarly, an output of 0V can be obtained only if the base voltage of T5 falls to –0.6V.

By adding bootstrapping capacitor C4, the output voltage swing is effectively added to the DC bias voltages. Thus, for the positive half-cycle, the positive change adds to the bias voltage at T4, causing it to conduct more current and produce a higher output voltage. Similarly, in the negative half-cycle, the negative-going swing reduces the quiescent bias voltage, helping T5 turn on harder and produce a lower output voltage.

An important aspect of amplifier design is power supply decoupling. When the output stage is producing full output power, the power supply delivers substantial peak currents. Under these conditions, it is possible that some of the audio signal appears on the supply line. To prevent this signal from affecting the operation of the rest of the circuit, it must be eliminated from that part of the supply feeding the voltage amplifier section. So resistor R6 is added together with C2 and ZD1 to maintain the amplifier’s supply voltage to a constant 10V.

Assemble the circuit on a general-purpose PCB and enclose in a suitable cabinet. Mount the diodes, electrolytic capacitors and transistors with the correct polarity. Output transistors T4 and T5 have a metalised surface on one side, which should face the centre of the board. A heat-sink is required for both the transistors. Either a small (20mm²) piece of aluminium or a commercially available heat-sink can be used. The heat-sinks on T4 and T5 should be insulated from the transistors with a piece of Mylar or similar material, as this transistor (and therefore the heat-sink) connects directly to the power supply.

Before applying power to the circuit, connect an 8-ohm load (resistor or loudspeaker) to the output, and capacitor C1 between the input terminal and the volume control. Set the volume control to minimum and then apply power—either from the plug pack or an external 12V DC supply.

Ensure that both the output transistors are cool when touched. If not, try adjusting preset VR3. The correct setting for VR3 should give a quiescent collector current of around 100 mA through T4 and T5.

USB Charger for Mobile Phones

All of us worry about our mobile phone draining out of charge while travelling. In such a situation, this SMPS-based USB charger powered by just two AA-size batteries will come handy. The advantage of SMPS is high efficiency and low cost. Of course, most mobile phones can also be charged through the standard USB port available in desktop and laptop computers.

A unit load is 100 mA in USB 2.0, and 150 mA in USB 3.0. An individual device may draw a maximum of 5 units load (500 mA) from USB 2.0 and 6 units (900 mA) from USB 3.0.

This USB charger for mobile phones operates off a 2.4V or 3V battery. It is designed around an average input-current-controlled buck-boost DC-DC converter LTC3127 (IC1) and some discrete components. The circuit converts 3V or 2.4V input into 5V output.

Pins SW1 (pin 2) and SW2 (pin 11) are used to connect the inductor. SHDN (pin 4) shuts down the output of LTC3127 when low. Pin 5 is used to change the mode of operation between PWM and burst modes. If Mode pin is low the mode will be PWM; when it is high the  mode will change to burst mode. PROG (pin 6) is used to set the average input current limit threshold. Vc (pin 9) is used to connect the compensation components, which impart stability to this regulator.

The values of R1 and R2 decide the output voltage level as follows:
V_OUT = 1.195×1 + R2R1

You can select appropriate values of R1 and R2 to get 5V output (V_OUT).

Most mobile phones have a USB male connector for charging, so a female connector is required for the charger side. Assemble the circuit on a small PCB and enclose in a suitable cabinet. Use a USB female connector and solder the connections as shown in the figure. The table gives the pin details of a USB connector. For powering the circuit, use an AA-size battery pack having either two 1.5V alkaline batteries or two 1.2V (Ni-Cd or Li-ion) batteries.