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WEEK 3

IMPROVEMENT OF THE IDEA OF THE PRODUCT

For week 3, after further meeting and discussion with Dr. Masum, the product design that had been proposed on week 2 was not suitable with the requirement. This is because the scissors mechanism that I suggested on week 2 were quite complex and will cost more for the project.

Since this project aims to help wheelchairs user and anyone could afford to have this product. So this product is most likely affordable, easy to use and attachable to any kind of wheelchair.

The new improvement of the product suggested by Dr. Masum required both in hardware and software. Thus he suggested to make a new design of product and also to understand the mechanism featured in the product. This project required 2 sensor; gyro sensor and tilt sensor. For the controller, I use arduino uno.

For this week, I am given a task to find the required component (sensor and controller) and to understand all the mechanism related to this project.

Gyro Sensor

      

Tilt Sensor 

             

Controller : Arduino Uno

For each of the component have their own working principle. So below is how each of the component works:

TILT SENSOR

Tilt sensors are devices that produce an electrical signal that varies with an angular movement. These sensors are used to measure slope and tilt within a limited range of motion. Sometimes, the tilt sensors are referred to as inclinometers because the sensors just generate a signal but inclinometers generate both readout and a signal.

Tilt Sensor working

These sensors consist of a rolling ball with a conductive plate beneath them. When the sensor gets power, the rolling ball falls to the bottom of the sensor to form an electrical connection. When the sensor is tilted, the rolling ball doesn’t fall to the bottom so that the current cannot flow the two end terminals of the sensor.

Tilt Sensor Circuit

Required components for tilt sensor circuit:

·         Tilt Sensor

·         470 Ohms Resistor

·         Led or Load

·         DC Voltage Source

A basic circuit that uses a tilt sensor is shown below.

Tilt Sensor Circuit 

When the device gets power and is in its upright position, then the rolling ball settle at the bottom of the sensor to form an electrical connection between the two end terminals of the sensor. Next the circuit becomes short circuit and the LED gets sufficient current. If the circuit gets tilted so that the rolling ball doesn’t settle at the bottom of the sensor with the electrical conduction path, then the circuit becomes open. This is about the circuit operation.

GYRO SENSOR

Gyro sensors also known as angular rate sensors or angular velocity sensors, are devices that sense angular velocity.

ARDUINO UNO

An Arduino is actually a microcontroller based kit which can be either used directly by purchasing from the vendor or can be made at home using the components, owing to its open source hardware feature. It is basically used in communications and in controlling or operating many devices.

Arduino Architecture:

Arduino’s processor basically uses the Harvard architecture where the program code and program data have separate memory. It consists of two memories- Program memory and the data memory. The code is stored in the flash program memory, whereas the data is stored in the data memory. The Atmega328 has 32 KB of flash memory for storing code (of which 0.5 KB is used for the bootloader), 2 KB of SRAM and 1 KB of EEPROM and operates with a clock speed of 16MHz.

Arduino Uno Architecture

Arduino Pin Diagram:

A typical example of Arduino board is Arduino Uno. It consists of ATmega328- a 28 pin microcontroller.

Arduino Pin Diagram

Arduino Uno consists of 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. 

For week 4, maybe I will start to make a prototype and test all the component with my supervisor.