This project is done by a group of students from Singapore Polytechnic, School of Electrical and Electronics Engineering. We have a total of 5 members in our group, Siti 'Atikah Bte Mohd Raba'i, Nurridzuan Bin Supardi, Chen Xitong, Toh Lee Ting and Yang Shi Xiang. Our supervisor is Mr Teo Shin Jen.
The concept of our prototype:
The automatic braille is a device to assist the visually impaired to "read" text messages, especially those text messages that are displayed at train stations. This system essentially is an english text to braille conversion with the use of a microcontroller and solenoids.
This project has 2 parts. The input part consist of standard lab issued keypad, that is used to enter english text in the form of ASCII code, the output part consist of 6 solenoids to protrude the ASCII equivalent character in braille. The algorithm "scroll" through the english text character by character and then turning on/off the solenoids to form the corresponding braille character.
Skill level: Basic soldering and C++ programming skills.
Components you'll need:
6 Solenoids to display 1 braille character (extendable with more solenoids to cover more braille characters)
Rainbow Ribbon Cables
12V DC Voltage Supply
Current for the Solenoid Motors : 1.5A
Step 1: Building the circuit board.
We have used a veroboard to standardize the supply & data to the solenoids.
Please refer to the schematic at the next step.
Step 2: Connecting the PIC18 Micro Controller
Port A (RA0-RA5) of the micro controller is connected to the solenoid motors.
Port B (RB0-RB7) of the micro controller is connected to the keypad.
Port D (RD0-RD7) of the micro controller is connected to the LCD.
Step 3: Solenoid Motors
The standard lab issued solenoids does not have a spring that prevents the iron slug from falling out. Coiling in the springs manually to ensure that the iron slug will be either pushed up or down.
Step 4: Putting everything together
The rainbow ribbon cables are connected to micro controller, input and output devices. We used a 12V DC voltage supply to the solenoid motors.
Ball typed magnets are placed on top of the pistons of the solenoid motors as indicator. It is placed in such a way that the magnets will pop up and down in response to the message being typed. Ball shape has a nicer touch and feel.
The algo: user enter english text with ASCII equivalent into the system, character by character. The ASCII value is then used in the lookup table to perform 2 actions: turning on/off the respective solenoids, display as english text for normal user.
The code is attached below.