Patient assistance robot is an idea that evolved from the need of living an independent life. Home automation is also incorporated along with the intended system, for the ease of control of appliances. A home based healthcare system is preferred as most of the bedridden patients would stay at home, clinging to the bed. These people would be in need of water or medicines many times a day, and hence calls out for a need of care takers to be on their toes round the clock. It is to avoid this issue; a patient assistance robot which will bring the required stuff has been developed. The patient assistance robot is equipped in such a way that, it carries out necessary ADL (Activities of Daily Life), like getting water and medicines. The robot responds to the patient voice and brings the specified item. The robot moves in a predefined path from patient to the table where these are kept and vice versa. The robot also gives indication of low battery, to prevent power drain. Voice of patient is recognized, decode the message and to respond accordingly with the help of an android application converts this speech to text, which is serially transmitted to the micro-controller to perform the task. The user can also make necessary calls to saved contacts with the application provided.

Step 1: What Is Needed ?

Arduino Nano - 3
DC gear motor 12V 100rpm - 2
L298 Dual H bridge motor driver - 1
Metal gear servo motors - 5
Servo brackets and accessories
Arm gripper
Robot chassis - 2
Wheels - 4
Bluetooth module - 1
Xbee module - 2
Relay - 2
Wires
Ultrasonic sensor - 2
Buzzer
LED - LDR array

Step 2: What All Things It Can Do?

Pick and place the required stuff for the patient
Can be controlled using android app with voice commands
Can able to control home appliances
Obstacle detection

Step 3: Working - Line Follower

This robot's motion is implemented using a line following principle. Here in this robot I have used LED-LDR array to detect the black line in a light color surface. An resistor is connected in series with LDR and the drop across this resistor varies as the reflected light intensity varies. The voltage drop across the resistor fed to the ADC of micro-controller to follow the black path. LED lights are used to increase the sensitivity at the LDR side. It's working is just like a line follower robot.

An array of five LEDs and LDRs was used for line follower motion in the five LEDs helped to trace the black line. The robot travelled forward when all the middle led is on black line and other LEDs facing a lighter complexion. According to the LEDs off position the value of LDR changes and right or left direction motion is taken. The values of each LDR were taken into account to calculate the extent of deviation and make appropriate delay to continue the motion to specific direction. As here only a straight and shorter distance path is to followed, it was thought to drop the use of extra LEDs and to keep the design simple by limiting the number of led and LDR to three.

Step 4: Obstacle Detection

Ultrasonic sensor was embedded in front of the robot to avoid collision and notify the caretaker if the distance to obstacle is less than a predetermined limit. Bluetooth based application was developed and installed within the project which can reduce the patient constraints. The time required by the pulse travel back after reflection from obstacle is to be converted into some distance units as meters or inches by conversion formulas.

When an obstacle is detected in its path, it alert this by using a buzzer.

Step 5: Robotic Arm

The robotic arm which is equipped to grab the requested necessity was assembled and programmed to pick and place. The grabbing action of robotic arm is 360 servo motors was decided to use for grabbing action. But, to perform controlled movement or rotation these servo motor creates complication for the same. Hence, 1800 servo motors replaced them and provided better grip to hold the carrier.

Step 6: Home Automation

In order to perform home automation separate unit with Bluetooth connectivity was integrated to the appliance control that according to commands switches them. Bluetooth has only a range of 100 m hence, Xbee with low power consumption and larger range is used for switching control of electrical appliances. Errors came up while coding Bluetooth connectivity which required partial or complete reconfiguration of the setup. The home automation circuit setup, and output obtained for the command Light ON, Light OFF, Fan ON and Fan OFF. The figure also shows the converted text message displayed in the application according to the patient voice commands. The home automation i. e. the control of light and fan is done in another micro-controller at the switch board. A series of LEDs and a miniature fan is controlled via app.

Step 7:

The completed setup of the Patient Assistance robot. The base is made using a metal chassis –wheel arrangement which works on the principle of LED - LDR array. The LED- LDR array is mounted under the robot, chained wheel arrangement is made for movement. The battery for power supply and robotic arm is mounted on the chassis such that their weights are balanced. An ultrasonic sensor is fixed on the robot and other on the arm.Ultrasonic sensor on the arm is used to detect the position of the stuff where it is placed. The Bluetooth module and Xbee module are also fixed with the micro-controller