Introduction: Braille Language Enabled Cell Phone for Visually Impaired People
The mobile phones today have changed human lives in many ways. There is great need to extend various features provided by cell phones for blind person. We strongly believe that these benefits will contribute at large and will increase exponentially work efficiency for Visually Impaired People. Propose project is about a mobile cell phone design which shall act as essential handled device for visually Impaired People that can be used for reading SMS effectively. The main Objective behind this idea is to make the communicator as compact as possible so that it could be portable for VIP. The cell phones will be user friendly and the VIP‟s won‟t feel hesitated while using this kind of cell phones.
The proposed design would be the first of its kind as the new kind of display is being used which is made of Motor Matrix that is only designed for the Visually Impaired People. Having such a communicator this sightless person can read SMS with ease.
Mobile Cell-phones are already available in the market but they are not user friendly with the Visually Impaired People. So it is basically a new kind of cell-phone for the Visually Impaired People which would be user friendly for them. Keeping this in mind a special kind of display which would be a Matrix of Small Dc Motors is provided. Basically Whatever Message received by the cell phone would be converted in the Braille language i.e. dot language and then it would be given to the Dc motor Matrix and accordingly the Particular Motors would be in motion and the rest would be stationary. By sensing these motors with their index finger the sightless person would easily understand the message
Step 1: Working Description
GSM module sends 8 bit ASCII Code to microcontroller. Microcontroller converts 8 Bit ASCII Code to Braille language according to the look-up table which is stored in its memory and transfer it to latch IC through decoding selection. Decoder will select 74373 latches IC at a time while disabling all other latch ICs. The selected Latch IC will give input to Braille display. Above in video as an example the message “HIE” has been taken and it is shown that the same message which is “HIE” is displayed on the output section in Braille Format.
There is one innovative feature in our purpose system which we call braille phone locator,
Assume one condition if blind person forgot the location of mobile where they kept then this feature come in function, he/she just need to press button of the circuit which we have provided to wear on wrist.
After pressing this button four bit binary code get generated which is uniquely coded and transmitted via RF frequency in 100 meters of range, cell phone is in build with RF receiver which can sense the signal and trigger an Alarm.......
Step 2: Hardware Requirement
Main Board :
8"x 6" copper clad board
10 uf x 7
33pf x 2
0.1uf x 5
2000uf x 1
1N4007 x 4
LED x 2
RLP434(RF receiver 434 MHz) x 1
Buzzer x 1
DB 9 connector X 1
BC 557 x 1
10k x 5
20k pot x 1
330E x 3
68K x 1
1k x 1
SPST switch X 1
AT89V51RD2 x 1
74HC137 x 1
74LS373 x 6
MAX 232 x 1
IC 7805 x 1
11.0592 MHZ Crystal x 1
7 pin connector x 6
2 pin connector x 3
HT12D IC x 1
Braile Display section :
4" x 4" copper clad board X 2
Small DC motors X 36
LED X 36
330E X 36
Male Bug strips x 36
Mobile locator tracker Transmitter section :
2" x 3" copper clad board x 1
HT12E x 1
RF transmitter 434 MHZ x 1
0.1 uf x 1
10k x 4
47 k x 1
8 pin switch x 1
Step 3: Hardware Details
# 80C51 Central Processing Unit 5 V
# Operating voltage from 0 MHz to 40 MHz
# 16/32/64 kB of on-chip Flash user code memory with ISP (In-System
# Programming) and IAP (In-Application Programming)
# Supports 12-clock (default) or 6-clock mode selection via software or ISP
# SPI (Serial Peripheral Interface) and enhanced UART
# PCA (Programmable Counter Array) with PWM and Capture/Compare functions
# Four 8-bit I/O ports with three high-current Port 1 pins (16 mA each)
# Three 16-bit timers/counters
# Programmable watchdog timer
# Eight interrupt sources with four priority levels
# TTL- and CMOS-compatible logic levels
# Brown-out detection
# Low power modes
# Power-down mode with external interrupt wake-up
# Idle mode
Small DC motor:
These days miniature vibrating motors are used in a wide range of products like cell phones, scanners, medical instruments, GPS, and control sticks. These motors are used in project as a sensing element for blind. By feeling its rotation, it is trying to transfer some information
The internal motor design is the same as our standard DC vibration motors, so you can expect the same high performance. An advantage to enclosing the motor, aside from having no external moving parts, is the increased resistance to dirt and larger particles compared with regular DC vibration motor designs. Enclosed motors differ from encapsulated motors because they do not have sealed and water resistant casings. However, one of their biggest benefits is that their encasing includes mounting fixtures to easily screw and secure the motor in order to vibrate panels and housings such as hoppers or containers. The ratings of single motor are:
Voltage = 3 volts
Current consumption = 250 Ma
Power rating 3v*250mA = 750mw
It is use to provide serial data through 9-pin connector to serial to parallel converter(74164).it provide data in form of 7bit ASCII Code. It works on AT-commands which are given through laptop or computer. Full Type Approved Quad Band Embedded GSM Module (GSM 850/900 1800/1900)  with AT command  set and RS232 interface on CMOS level. This GSM wireless data module is the ready a solution for remote wireless applications, machine to machine or user to machine and remote data communications in all vertical market applications.
Other Features :
Highly Reliable for 24x7 operations with Matched Antenna .
Status of Modem Indicated by LED .
Simple to Use & Low Cost.
Quad Band Modem supports all GSM operator SIM cards.
LCD 16 x 2 cryastal display:
It is a 16 x 2 character LCD display . It shows which message is received and GSM Modem detection. It is used in this project for demo purpose only. It has 2 lines of 16 characters and compatible interface for easy connections to micro controllers.
RF transmitter and receiver:
Pin 1: Antenna
Pin 2: Data in
Pin 3: Ground
Pin 4: VCC
Description: The TX4915 is low power ASK transmitter IC intended for applications in the North American and European VHF/UHF and ISM bands. The integrated voltage-controlled oscillator (VCO), phase/frequency detector, pre scalar, and reference oscillator require only the addition of an external crystal to provide a complete phase-locked loop (PLL). In addition to the standard power-down mode, the chip also includes an automatic lock-detect feature that disables the transmitter output when the PLL is out-of-lock.
433.92 MHz 5 – 12V Single Supply
Operational OOK / ASK Data Format
Up to 9.6 kbps data rate, 4 Pin compact size modules
Vertical / Horizontal mount
Low Power Consumption suitable for battery operated devices
The RX3400 is a low power ASK receiver IC which is fully compatible with the Motel KESRX01 IC and is suitable for use in a variety of low power radio applications including remote keyless entry. The RX3400 is based on a single-conversion, super-heterodyne receiver architecture and incorporates an entire phase-locked loop (PLL) for precise local oscillator generation.
Extremely low power operation
Low external part count
Receiver input frequency: 290 – 460 MHz
On-chip VCO with integrated PLL using crystal oscillator reference
PLL power down feature
Integrated IF and data filters
SSOP-24 package (0.64 mm pitch)
In this project, buzzer is used for indication to VIP‟s in case if they misplaces their cell phone anywhere in their room. It is used with RF reciever circuit to find out cell phone in room.
Step 4: PCB Designing .......
Pcb designing carried out with Orcad software version 9.2,
you can download software from this link http://www.orcad.com/resources/orcad-downloads..
Follow this tutorial this URL https://www.youtube.com/playlist?list=PLC85F0C97B6... to learn orcad..
Once circuit design completed, we have attached the .pcb file a designed PCB Take print out of the Art work of that circuit layout on Photo paper or glossy paper then trace the printed art work of circuit on copper clad board by ironing process, During ironing process you must pay attention that all art work of circuit layout should traced completely on copper clad board , after tracing art work of circuit layout on copper clad completely, make solution of Fecl3 with water and keep it traced copper clad into that solution about 30 to 40 minutes ...... during this process you should continuously check the copper clad within some interval, copper of copper clad board should disappear except traced part of art work of circuit layout...... means only circuit should remain...Once it complete take out board from solution then clean it and polish with sand paper for drilling , after drilling holes apply soldering flux and complete tinning process with the help of soldering iron after tinning start mounting component and soldering operation .........
Step 5: Making of Braille Display...
single braille character made up of six dots in arrangement of 3 x 2 format
To make braille display do following steps:
1. Take an thick acrylic sheet of 4 x 4 inch
2. Make six holes in combination of 3 x 2 to form one character where the diameter of the hole is slightly grater than our small dc vibrator motor
3.Now fix all motors in that holes and make connections on the braille display circuit board which we have made in circuit designing step
we have made an example display of six character which you can see above.
for conformation of incoming message we have build display using led which we can observe an compare with braille chart for acknowledgement.