Cellphone(Mobile) Batter Charger Schematic Circuits with Explanation

Charging of the mobile phone, cellphone battery is a big problem while traveling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless.
A fully charged battery becomes necessary especially when your distance from the nearest relay station increases. Here’s a simple charger that replenishes the cellphone battery within two to three hours. Basically, the charger is a current-limited voltage source. Generally, cellphone battery packs require 3.6-6V DC and 180-200mA current for charging.
These usually contain three NiCd cells, each having 1.2V rating. Current of 100mA is sufficient for charging the cellphone battery at a slow rate. A 12V battery containing eight pen cells gives sufficient current (1.8A) to charge the battery connected across the output terminals. The circuit also monitors the voltage level of the battery. It automatically cuts off the charging process when its output terminal voltage increases above the predetermined voltage level.








Parts:

P1 = 20K
P2 = 20K
R1 = 390R
R2 = 680R
R3 = 39R-1W
R4 = 27K
R5 = 47K
R6 = 3.3K
R7 = 100R-1W
C1 = 4.7uF-25V
C2 = 0.01uF
C3 = 0.001uF
D1 = 5.6V-1W Zener
D2 = 3mm. Red LED
Q1 = SL100

S1 = On/Off Switch
B1 = 1.5vx8 AA Cells in Series
IC1 = NE555 Timer IC





Timer IC NE555 is used to charge and monitor the voltage level in the battery. Control voltage pin 5 of IC1 is provided with a reference voltage of 5.6V by zener diode D1. Threshold pin 6 is supplied with a voltage set by P1 and trigger pin 2 is supplied with a voltage set by P2. When the discharged cellphone battery is connected to the circuit, the voltage given to trigger pin 2 of IC1 is below 1/3Vcc and hence the flip-flop in the IC is switched on to take output pin 3 high. When the battery is fully charged, the output terminal voltage increases the voltage at pin 2 of IC1 above the trigger point threshold.
This switches off the flip-flop and the output goes low to terminate the charging process. Threshold pin 6 of IC1 is referenced at 2/3Vcc set by P1. Transistor Q1 is used to enhance the charging current. Value of R3 is critical in providing the required current for charging. With the given value of 39-ohm the charging current is around 180 mA. The circuit can be constructed on a small general-purpose PCB.
For calibration of cut-off voltage level, use a variable DC power source. Connect the output terminals of the circuit to the variable power supply set at 7V. Adjust P1 in the middle position and slowly adjust P2 until LED (D2) goes off, indicating low output. LED should turn on when the voltage of the variable power supply reduces below 5V. Enclose the circuit in a small plastic case and use suitable connector for connecting to the cellphone battery.






Note:

This circuit was tested with a Motorola make cellphone battery rated at 3.6V, 320 mAH. In place of 5.6V zener, a 3.3V zener diode was used. The charging current measured was about 200mA. The status of LED is shown in the table.

Incoming Call Indicator for Mobile

This circuit can be used to escape from the nuissance of obile phone rings when you are at home.This circuit will give a visual indication if placed near a mobile phone even if the ringer is deactivated.

When a call is coming to the mobile phone, the transmitter inside it becomes activated.The frequency of the transmitter is around 900MHz.The coil L1 picks up these oscillations by induction and feds it to the base of Q1.This makes the transistor Q1 activated.Since the Collector of Q1 is connected to the pin 2 of IC1 (NE555) , the IC1 is triggered to make the LED connected at its output pin (pin 3) to blink.The blinking of the LED is the indication of incoming call.

Notes:

• The coil L1 can be made by making 150 turns of 36 SWG enameled copper wire on a 5mm dia plastic former.Or you can purchase a 10 uH coil from shop if available.
• The circuit can be powered from a 6V battery.
• Assemble the circuit on a good quality PCB.
• C1 & C3 are to be polyester capacitors.
• The electrolytic capacitor C2 must be rated 10V.

Acknowledge Why the future of mobile is screenless, touchless?

A phone today is a a value-added service, a ‘teleputer,’ a creature born with genes coming from a cell phone and a personal computer,” according to independent researcher Szymon Slupik.

Speaking yesterday at the invitation-only Emerging Communications Conference & Awards (eComm), the Krakow-based futurist explained that by 2020, a mobile phone as we know it will disappear, evolving into a device linking our senses directly with senses of other people or with machines. What device will displace the role of today’s smartphone: Internet glasses.

“Voice was always organized in sessions with a beginning and an end. Today we have threads. So when a thread is started it never ends and we have many continuing in parallel. Think of your email, RSS feeds, Twitter, etc. So this is how our brain works. The phone of tomorrow will be telecoupling us and machines,” Slupik said. This is analogous to acoustic coupling, information will be transmitted directly to our brains via wireless gateways.

So how do we get there and when? The key, said Slupik, is to bypass tiny screens and keyboards altogether and look to emerging technologies that can free up the bandwidth bottlenecks caused by aging paradigms. Think “screenless instead of better screens. Touchless instead of better touch.” The two key technologies:

1. Laser based displays - MEMS (microelectromechanical systems)-based laser projectors can display images directly on our retinas while not blocking our sight, enabling mixed reality vision. The beauty is that it is so small that it can already be integrated into eyeglasses.
2. Brain waves sensing - We need to control the functions by the mind to become really hands free. Aided by eye tracking, direct brain links will provide touchless input. Sound far fetched? It’s not. Major universities continually report progress with brain implants used in lab rats and humans, while commercial applications for noninvasive coupling with human brain signals are also emerging. A Japanese company recently announced cat ears that can be worn on the human head and manipulated with nothing but the mind.

Slupik believes that we are on the verge of a hardware revolution that will allow for computer senses and the brain to be networked by the end of this decade. The result will be an unleashing of unimaginable usage scenarios. Computers in the cloud will be fully aware of our context, receiving a continuous stream of what we hear and what we look at and, in turn, sending us back contextually-aware information, such as hints, translations, and guidance.

After his talk, Slupik gave me another example. Imagine remotely flying a drone equipped with a camera somewhere in Australia and being able to see the image projected on your eyeglasses. In effect, you’ll will be able to hear with somebody else’s ears and see with somebody else’s eyes.

S:www.zdnet.com