12-06-2012, 04:09 PM
PROJECT REPORT ON MOBILE CHARGER
MOBILE CHARGER.doc (Size: 145 KB / Downloads: 104)
INTRODUCTION
Cell phone charging is a problem when you are away from home or where main source is not available. A fully charged phone may last its battery up to 3 to 8 hours depending how it is used. When you are out for picnics, camping, and or having adventure with your cell phone battery empty, you cannot receive calls, take pictures or listen to music, thus a simple and portable mobile charger is a need.
A good charger has an output of 4V DC to 8V DC and a current capacity of 100mA up to 500mA.With this charger capacity, standard 3.7V at 850mA battery can be charged up to 2 hours to 4 hours.
BLOCK DIAGRAM DESCRIPTION
Sensing process: In this process LDR is used as a sensor. When any vehicle crosses the first laser light beam, LDR1 will trigger IC1. The output of goes high for the time set to cross 10 meter with the selected speed and LED1 glows during for period.
Counter: In this after sensing, the counter starts counting when the first laser beam is intercepted and stops when the second laser beam is intercepted. The time taken by the vehicle to cross both the laser beam is displayed on the 7-segment display.
Digital Display Device: These devices are used in the final stage of any measurement for presentation of the output. And also these devices are used for indicating the output. These devices indicate the value of measure and in the form of decimal number. These are cheap and simple. The power requirement is considerably smaller, since the output of digital device is in digital form and therefore the output may be directly fed into memory devices like floppy discs, tape recorders etc for future computations.
CIRCUIT DIGRAM DESCRIPTION
It has been designed assuming that the maximum permissible speed for highways is either 40 kmph or 60 kmph as per the traffic rule. The circuit is built around five NE555 timer IC’s (IC1 through IC5), four CD4026 counter IC’s (IC6 through IC9) and four 7- segment displays (DIS1 through DIS4). IC1 through IC3 functions as monostables, with IC1 serving as count-start mono, IC2 as count as mono and IC3 as speed detector mono, controlled by IC1 and IC2 outputs. Bistable set-reset IC4 is also controlled by the outputs of IC1and IC2 and it (IC4), in turn, controls switching on/off of the 100 Hz astable timersIC5. The time period of timer NE555 (IC1) count-start monostable multiviberator is adjusted using preset VR1 or VR2 and capacitor C1. For 40 kmph limit the time period is set for 9 seconds using preset VR1, while for 60 kmph limit the time period is set for 6 seconds using preset VR2. Slide switch S1 is used to be select the time period as per the speed limit (40 kmph and 60 kmph respectively). The junction of LDR1 and resistor R1 is coupled to pin to of IC1. Normally, light from the laser keeps falling on the LDR sensor continuously and thus the LDR offers a lower resistance and pin2 of IC1 is high.
WORKING
When any vehicle crosses the first laser light beam, LDR1 will trigger IC1. The output of IC1 goes high for the time set to cross 10m with the selected speed (40 kmph) and LED1 glows during for period.
When the vehicle crosses the second laser beam light, the output of IC2 goes high and LED2 glows for this period. Piezobuzzer PZ1 sounds an alarm if the vehicle crosses the distance between the laser setups at more than the selected speed (lesser period than present period). The counter starts counting when the first laser beam is intercepted and stops when the second laser beam is intercepted. The time taken by laser beam is displayed on the 7-segment display.