The project mainly introduces K-Ability a disabarished keyboard that can be applies to touch screen
K-ABILITY is a physical keyboard that allows personal use of touch screen equipment for individuals with pathological diseases that lead to neuromuscular disease.
There are many auxiliary tools to help people with neuromuscular lesions use computer equipment, but they are very expensive, and most of the auxiliary tools do not allow complex touch screen gestures on mobile devices (slide, double click, drag and drop).
K-ABILITY V1 is designed to create a cheap equipment (less than 20 euros) that makes people with tremor, spasm, and more common control and neuromuscular coordination, can use mobile devices and computers in a reasonable price.
K-ABILITY consists of 7 buttons and a small OLED screen.
At the same time, several new features have been introduced, adding comfort and ease of use:
Use a capacitance button instead of the physical button
HID Bluetooth is connected to the master (smartphone, tablet and computer)
Can be powered from mobile power or external battery
Create the possibility of custom design
Step 1: Supplement list
Material
Arduino nano
HC-05
OLED display 6PIN
MPR121 Capacitive Touch Sensor Controller
Resistor
cable
Breadboard
tool
FTDI serial adapter
Step 2: Turn HC-05 into HID Bluetooth devices
L'RN-42 is a Bluetooth module that acts like a wireless keyboard or mouse.
Due to high cost and transportation time, I chose to crack common and cheap HC-05, which is attributed to this simple and effective guide written by Brian:
https://www.instructables.com/id/upgrade-your-3-bl ...
This program is very simple, you only need a FTDI board and some software that can be downloaded directly from the guide.
At the end of the program, your HC-05 module will be able to run in a manner similar to RN-42 and any other HID Bluetooth module.
Step 3: Circuit
This circuit uses 9 GPIO in this configuration:
D02 > HC-05 TX
D03 > HC-05 RX
D04 > HC-05 State
D08 > Show RES
D09> Display DC
D11 > Show SDA
D13 > Display SCL
A4 > MPR121 SDA
A5 > MPR121 SCL
Note that the MPR121 module is powered by 2 resistors of 3.3V and HC-05 voltage divisors.
Step 4: Framework
The description items do not have a real fixed frame because each pathology requires dedicated shape, size, and material.
In this guide, I made a simple cardboard framework to show the possibility of using any shape and material.
Make sure the simplest part of the body structure is that it does not have a tactile button.
With the MPR121 module, the use of capacitive buttons ensures 7 inputs, just connect the cable or any other conductive material to the module's pin, you can make a keyboard layout and create a frame and a button any size is very simple.
Ka_Prototipo.ai
Step 5: Firmware
First we need some code:
Plain text Arduino library for SSD1306 OLED displays
Adafruit MPR121 library
SPI
Software serial
The command of the mouse cursor is sent by a software serial library with a "write" function.
Each command consists of a 7-byte buffer, the structure is as follows:
Buffer [0] = 0xFD;
Buffer [1] = 0x05;
Buffer [2] = 0x02;
Buffer [3] = 0x00; // button
Buffer [4] = 0x00; // X Mobile
Buffer [5] = 0x00; // y
Buffer [6] = 0x00; // Wheels
For this project, I chose "text only" because it uses only 2928 bytes (9%) program storage space and global variables using 54 bytes (2%) dynamic memory.
Each command consists of a 7-byte buffer, the structure is as follows:
Buffer [0] = 0xFD;
Buffer [1] = 0x05;
Buffer [2] = 0x02;
Buffer [3] = 0x00; // button
Buffer [4] = 0x00; // X Mobile
Buffer [5] = 0x00; // y
Buffer [6] = 0x00; // Wheels
For this project, I chose "text only" because it uses only 2928 bytes (9%) program storage space and global variables using 54 bytes (2%) dynamic memory.
Video Demo:
Our other product:
