Patient Monitoring Smart Wheelchair

As part of my final year project our team chose the topic as Patient Monitoring Smart Wheelchair. We wanted to make something for the society. As a part of one of my earlier projects Improving Infrastructure for specially challenged citizens in Vashi we had conducted a survey. We found out that the existing infrastructure in Vashi(Navi Mumbai, India) is not at all disabled friendly and same is the situation in majority of India. On top of that the modern assistive technology is too expensive for the common man or aam aadmi.

proportion of diabled population

Above figure shows the percentage of disabled population to total population in India as per 2011 census. In states like Maharashtra, Andhra Pradesh etc. the percentage is very high.

type of disability

Above figure shows the proportion of disabled population by type of disability. We can see that disability in movement accounts for 20.3 % and multiple disability 7.9%. This led us to the idea of making a smart wheelchair.

rural vs urban

This shows that a major chunk of the disabled population lives in rural India. Our market analysis led us to the finding that all the modern electric wheelchairs available in the market have outrageous price tags.

market analysis

So we decided that our wheelchair would be affordable. Then depending on the analysis of disabilities we found out which all modes should be incorporated into this smart wheelchair.

The modes selected are :

  • Voice control mode
  • Gesture control mode
  • Joystick control mode

Patient monitoring was thought of as an added service. Initially the plan was to measure heart rate, body temperature and blood pressure. But due to time constraints we limited to just measuring body temperature and displaying it on a LCD.

Here is a short video of the completed project.

The bill of materials is as follows.

bom

As you can see we achieved the cost reduction. So that is all from my side in this post. Thank you for patiently reading this and reaching till the end. If you people want a post about the technical details I will require at least 10 Word press likes Winking smile. Share with as many as you can. Maybe someone will take this idea to the next level. Thank you once again for reading this post.

 

P.S: I just felt like sharing this news article with you all.

http://economictimes.indiatimes.com/news/politics-and-nation/government-set-to-bring-private-sector-under-the-new-disability-legislation/articleshow/48780998.cms

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Gesture control for PowerPoint presentation

Basic idea of the project

The intention of this tutorial is to learn how to control computer keyboard and mouse events using your micro-controller. For demonstration I have chosen to name the project as gesture control for PowerPoint presentation. At the end of this tutorial you will be able to control the slides using your gestures. Now in order to control the operating system you need a language like python, java, c++ etc. I find python affable and powerful so I’ll be using that for coding. You can use any language you want but the logic and algorithm will remain the same, only the syntax will differ. I won’t be teaching you python in this post that is beyond the scope of this post. If you want to learn the language there is plethora of content available online. You just need a net connection and off you go.
P.S. : If you like the posts do like and share them with others.

Python

Python is an easy to learn high level programming language. It is a beautiful and a very powerful language. The packages that are available make it kind of limitless. Some of the places where python is used are mentioned below.

  • Google makes extensive use of Python in its web search systems.
  • The popular YouTube video sharing service is largely written in Python.
  • The Dropbox storage service codes both its server and desktop client software primarily in Python.
  • The Raspberry Pi single-board computer promotes Python as its educational language.
  • NASA, Los Alamos, Fermilab, JPL, and others use Python for scientific programming tasks.

So we know that most of the big shots use python. Now they use it for a reason and the reason being that its simply an awesome language. If you want to start learning programming you ought to start with python. Here are a list of sites and books that you may use for learning python.

  1. https://www.python.org/about/gettingstarted/ (This is the official page where you can learn how to install the IDE and get started.)
  2. Learning Python, 5th Edition (This is a good book if you are new to programming and otherwise as well.)
  3. http://www.learnpython.org/
  4. http://www.tutorialspoint.com/python/

Once you get the hang of it then you can directly use the documentations for learning how to use the packages.

pySerial and PyUserInput

We will be requiring these modules in our project. The names are quite self explanatory the former is for serial communication while the latter is for the mouse and keyboard events. The links to these modules are:

Well download these and install them. I recommend you to use 32bit python 2.7 version modules as well as the language. Because most of the modules are available for 2.7 version.

Components and Software requirements

  • A microcontroller board with UART capability e.g. MSP430G2 Launchpad, Arduino Uno board etc.
  • An accelerometer e.g. ADXL335 etc..
  • Python 2.7 , pySerial & PyUserInput modules

Connections

connections

I have used fritzing for making this. Here is the link to their home page.  http://fritzing.org/home/

Logic

We will calibrate the accelerometer and take readings for left and right position. Use the serial monitor for this. Read my tutorial titled Capacitive Accelerometer Interfacing if you don’t know what I am talking about. Next once you have those digital values you need to make the program for slide control. We know that left arrow and right arrow keys are used for navigation purpose. So in our python script the if statements will contain code for left arrow button press and right arrow button press. Note that you are reading the values that the controller is sending serially using python and taking decisions based on that value.

Energia Code

int x_pin = A0;
void setup()
{
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(x_pin,INPUT);
  analogReference(INTERNAL2V5);
}

void loop()
{
  // put your main code here, to run repeatedly:
  int x = analogRead(x_pin);
  Serial.println(x);
  delay(500);
}

Python Script

__author__ = 'MANPREET'
'''
This is a file for controlling keyboard events.
'''
from pykeyboard import PyKeyboard
import serial
import time

comPort = raw_input("Please enter the COM port number")
baudRate = raw_input("Please enter the baud rate")
myserial = serial.Serial(comPort, baudRate)
k = PyKeyboard()
TRUE = 1;
try:
    while (TRUE):
        if (myserial.inWaiting()):
            mydata = myserial.readline()
            x = int(mydata)
            print(x)
            if x > 650:
                k.tap_key(k.left_key)
                print("left")
                time.sleep(1)
            if x < 550:
                k.tap_key(k.right_key)
                print("right")
                time.sleep(1)
except KeyboardInterrupt:
    print("stop")

Code Explanation

The Energia code is pretty straightforward but still just to cover that as well. We have declared A0 i.e. P1.0 pin as input and changed the ADC reference voltage to 2.5V in line 7. Next part is just getting the ADC reading and sending it serially.

The python code demands some explanation. So lets begin understanding the code .

from pykeyboard import PyKeyboard
import serial
import time

This code will import three modules PyKeyboard, serial and time. For the pykeyboard we have imported the constructor. Then you have made one object k using the same.

comPort = raw_input("Please enter the COM port number")
baudRate = raw_input("Please enter the baud rate")
myserial = serial.Serial(comPort, baudRate)
k = PyKeyboard()

myserial is an object of the serial module that you have imported. You will use this to access its functions. The raw_input() is for taking the com port and baud rate values from the user. Example COM11 and 9600.

TRUE = 1;
try:
    while (TRUE):
        if (myserial.inWaiting()):
            mydata = myserial.readline()
            x = int(mydata)
            print(x)
            if x > 650:
                k.tap_key(k.left_key)
                print("left")
                time.sleep(1)
            if x < 550:
                k.tap_key(k.right_key)
                print("right")
                time.sleep(1)
except KeyboardInterrupt:
    print("stop")

Well this is an infinite loop and you are checking this block for keyboard interrupt i.e. ctrl+c . This is done so that you can come out of the program properly without having to kill the program. Next we are checking if there is data in the serial buffer. If yes then we are storing it in mydata variable. Convert it into integer and store it as some variable say x. Next step is easy write two if statements and include the code and condition for left arrow button press and right arrow button press. For more details of the PyKeyboard module visit : https://pypi.python.org/pypi/PyUserInput/0.1.9
For running the python script install python 2.7. Copy paste the python script code into notepad and save it as gersturecontrol.py(or any name for that matter) Then follow these steps.

  1. Open command prompt(Press windows+r, then type cmd and press enter.)
  2. opening_command_prompt

  3. Change the directory to the one containing your python script i.e. the .py file. Use cd for that.
  4. file_location

  5. Use python gesturecontrol.py for running your code
  6. running the program

  7. For stopping the code press ctrl+c

Thank you for reading the post and hope that it was helpful.If you like the post do share it with others and spread the knowledge.

SIM 300/900 (GSM Module)

INTRODUCTION

SIM 300 is a GSM modem with a simple serial interface. SIM 300 modem can accept any GSM network operator SIM card and act just like a mobile phone with its own unique phone number. With this module one can send/receive sms, connect to internet via GPRS and receive calls. The modem can either be connected to PC serial port directly or to any microcontroller. When purchasing purchase the entire board. As it comes with RS232 to TTL converter and ethernet port. Also do check the module by calling a few times when in the shop.

You can purchase this module online. Some of the sites are listed below:

  1. http://www.nskelectronics.com/sim300_modem_with_rs232.html
  2. http://robokart.com/wireless-modules/gsm-gprs/sim-900a-gsm-gprs-modem.html

SIM300_INTERFACE_MODULE_RS232_TTL-500x500

Fig.1 SIM300 Module

There are two LEDs on the board. One is power LED and the other is the network LED. When you insert your SIM card into the slot and power ON the device the power LED will be turned ON. After few seconds the network LED will start blinking after an interval of 3 seconds. If this happens it means signal is proper but if it is blinking faster it means that there is no network. If your mobile phone has network then this module should have network at the same location(provided the antenna is connected.) Make a call and it should ring. Do it a couple of times before purchasing from a store.

AT commands

These are the Haye’s command set also called AT commands. AT stands for attention. These commands are used to control the modem. Using these commands the modem can be operated. There are different commands for sending/reading sms etc. For further information about the history you can read the Wikipedia article.

The AT command set can be downloaded here.

at_commands

Above table lists few of the commands. The most basic command is AT and the response is OK. If you get OK then it means that everything is working fine.

exteneded_at

Now to test out the commands or for direct interfacing with the PC or laptop you can use USB to RS232 adapter.

USBRS232Cable_1

Fig. 2 USB to RS232 Adapter

You will need to install prolific drivers. These will be included in a small CD that accompanies the adapter or you can download here.

Once you do that there will be a COM port available now. Some of the basic commands are explained in the following video.

Capacitive Accelerometer Interfacing

Well in this post I’ll be telling briefly what is an accelerometer and how to interface it with a microcontroller. To be honest I woke up in the middle of the night and couldn’t go back to sleep, so I decided to write this post which I was planning on writing for some time now.

Accelerometer

It is basically a device which is used for measuring acceleration or change in motion. You use one more often than you know. There is an inbuilt accelerometer in your cellular mobile phones and tablets. So now you know what is used for detecting the tilts in your phone. Next time you play temple run or similar game you would know that all this fun is possible due to a technology called accelerometer and other stuff. Then modern laptop hard disks have accelerometers to detect fall. If fall is detected the writing head in retraced so that the disk is not damages and there are no scratches. There are numerous other applications and examples. I just gave food for thought you can explore the rest on your own.

Types of Accelerometer

Well as you may have already guessed there are various types of accelerometers.

  • Capacitive Accelerometer
  • Magneto-resistive Accelerometer
  • Piezo-electric Accelerometer

There are various other types these three being examples.This is a video one of my instructors showed me. The guy explains the working and construction quite well.

This is an article having good information about accelerometers

http://www.engineersgarage.com/articles/accelerometer?page=1

Data from accelerometers

Now that you know how accelerometers work. Let’s come to the topic at hand i.e. using one with your microcontroller.

Well there are different types of accelerometers depending on the type and method of obtaining data. While the data acquisition may be different but processing part is same once you get the reading. So the data may be available as an analog signal or may be it may be available inside the accelerometer in a register which you need to access via a protocol like SPI etc..

ADXL 335

So I’ll be talking about this accelerometer. You can look at the datasheet before deciding to use it.

So this accelerometer gives the output as three analog signals. There are three pins x,y,z for the three axes. Then there is Vcc and GND.

For actually using this signals you need to convert them into digital form. For this you use the inbuilt 12bit ADC that is available in msp430g2553.(If your controller does not have an inbuilt ADC, which won’t be the case, you can use an external ADC or if your application requires faster conversion and better precision and stability then you can use external ADC.) So once you have the data in digital form, next step would be calibration of the accelerometer.

Calibration

Now you have the data in digital form but what to do with it and how to see it? The answer is you send the digital reading serially and observe it on a serial monitor. So you make variables and store the digital reading in those and view the numbers on screen. Now you will make a table for these variables and decide the limits. Suppose you want to detect forward tilt, you can note what are the range of values that the accelerometer gives for the gesture and the using a simple if statement write whatever you want your application to do on a forward tilt.

Position Digital Range of X Digital Range of Y
Forward N.A <658
Backward N.A >705
Left >497 N.A
Right <460 N.A
Stop 470 to 485 695 to 705

 

The above code is an example of finding the ranges. You can then use basic if else for this. If you want a video showing the calibration process do tell me.

Code for gesture controlled bot

void setup()
{
  pinMode(P2_0,OUTPUT);
  pinMode(P2_1,OUTPUT);
  pinMode(P2_2,OUTPUT);
  pinMode(P2_3,OUTPUT);
  pinMode(A0,INPUT);//X
  pinMode(A3,INPUT);//Y
  pinMode(P1_4,INPUT);
  //pinMode(A2,INPUT);//Z
  Serial.begin(9600);
  Serial.println("Start");
}
void loop()
{
  int x = analogRead(A0);
  int y = analogRead(A3);
  int m = digitalRead(P1_4);
  //Serial.print(x);
  //Serial.print(','); //use these lines for calliberation
  //Serial.println(y);
   if(y>520)
  {
  digitalWrite(P2_0,HIGH);
  digitalWrite(P2_1,LOW);
  digitalWrite(P2_2,HIGH);
  digitalWrite(P2_3,LOW);
  Serial.println("BACKWARD");
  //delay(100);
  }
  if(y<460)
  {
  digitalWrite(P2_0,LOW);
  digitalWrite(P2_1,HIGH);
  digitalWrite(P2_2,LOW);
  digitalWrite(P2_3,HIGH);
  Serial.println("FORWARD");
  //delay(100);
  }
  if(x>445)
  {
  digitalWrite(P2_0,LOW);
  digitalWrite(P2_1,LOW);
  digitalWrite(P2_2,LOW);
  digitalWrite(P2_3,HIGH);
  Serial.println("LEFT");
  //delay(100);
  }
  if(x<430)
  {
  digitalWrite(P2_0,LOW);
  digitalWrite(P2_1,HIGH);
  digitalWrite(P2_2,LOW);
  digitalWrite(P2_3,LOW);
  Serial.println("RIGHT");
 // delay(100);
  }
  if(x>430 && x< 445 && y>460 && y<500)
  {
  digitalWrite(P2_0,LOW);
  digitalWrite(P2_1,LOW);
  digitalWrite(P2_2,LOW);
  digitalWrite(P2_3,LOW);
  Serial.println("STOP");
  //delay(100);
  }  
}

(If you would like the embedded c code email me.)

P.S.

If you like my articles do like them. Well just want to say a little appreciation goes a long way. Thank you for reading the post.

A taste of Image Processing

Image processing involves extracting information from images and using the information so obtained for various operations and tasks. Don’t confuse image processing image processing with image manipulation that involves adjusting the images. Photoshop and similar software are used for image manipulation.

Application areas

  • Medical Applications
  • Industrial Applications
  • Military Applications: Some of the most challenging and performance-critical scenarios for image processing solutions have been developed for military needs, ranging from detection of soldiers or vehicles to missile guidance and object recognition and reconnaissance tasks using unmanned aerial vehicles (UAVs). In addition, military applications often require the use of different imaging sensors, such as range cameras and thermo-graphic forward-looking infrared (FLIR) cameras.
  • Law Enforcement and Security: Surveillance applications have become one of the most intensely researched areas within the video processing community. Biometric techniques (e.g., fingerprint, face, iris, and hand recognition), which have been the subject of image processing research for more than a decade, have recently become commercially available.
  • Consumer Electronics
  • The World Wide Web

So as we can see image processing has wide areas of application.

That being said you need some software or programming language for making this image processing possible. There are various ways by which this can be done. You can use c, NI LabVIEW, MATLAB etc. for image processing. For this post I’ll be using MATLAB. Now we did this just so as to understand the concepts of image processing. So if you feel that its meagre you can build on this.

Code

clc;
close all;
clear all;
video = videoinput('winvideo');%Create video variable

set(video,'FramesPerTrigger',1); % Setting frames per trigger
preview(video);%Preview the video
rgb_image = getsnapshot(video); % Storing Image in an array variable
[y x c]= size(rgb_image); % Determining the size of the captured frame.
x1 = (x/2)-(0.2*x);
x2 = (x/2)+(0.2*x);
y1 = (y/2)-(0.25*y);
y2 = (y/2)+(0.25*y);
global s;
s = serial('COM4')
fopen(s)
while(1)
image = getsnapshot(video);
fR = image(:,:,1);
fG = image(:,:,2);
fB = image(:,:,3);
I = fR>200;
se=strel('disk',5);
B=imopen(I,se);
final=imclose(B,se);
[L,n]=bwlabel(final);
for k=1:n
    [r,c]=find(L==k);
    rbar=mean(r);
    cbar=mean(c);
end
rbar
cbar
if x1<cbar<x2 &&  rbar<y1
    disp('Move forward');
    global s;
    fwrite(s,'w')
elseif cbar<x1 && y1<rbar<y2
    disp('Move right');
    global s;
    fwrite(s,'d')
elseif cbar>x2 && y1<rbar<y2
    disp('Move left');
    global s;
    fwrite(s,'a')
elseif x1<cbar<x2 && rbar>y2
    disp('Move back');    
    global s;
    fwrite(s,'s')
elseif x1<cbar<x2 && y1<rbar<y2
    disp('Move stop');
    global s;
    fwrite(s,'f')
end
end

Now this is the code. I am thinking I’ll just explain the logic and then you can use MATLAB help for the rest. Seriously the help provides is simply awesome. You can understand how the functions word using the help and then there is the world wide net. So I am assuming that those of you who has interest will read further.

Now let’s begin understanding the code.

video = videoinput(‘winvideo’);

This will create a video object from the available cameras. You can check the available ones by using imaqhwinfo

image

So for the windows winvideo is installed adapter.

image

Next give winvideo as the agrument to the imaqhwinfo(). Now if you have an external webcam connected to your computer you will se two device ID’s. So now suppose you want to know about the device with ID=1 all you need to do is pass device ID as second argument.

image

You can see the properties you the webcam.

So just use the videoinput() for creating a variable attached to the particular webcam in MATLAB. In our case video is the variable.

Next you set the frames per trigger i.e. whenever you give the capture commands how many frames will be captured every time.

Then you see a preview of the video feed so that you come to know what exactly is the camera viewing.

Next up you take a sample shot so as to determine the dimensions of the camera.

You will get a 3D matrix of the image. Extract the x and y resolution.

Now for this application what we will do is divide the webcam field into 9 quadrants and take decision depending on position of the image of the object to be detected.

Now since we wanted to learn the basic we used white light such as a torch as the source. If you have a proper webcam and good lighting conditions you can detect normal coloured balls using this program. All you need to do is some thresholding.

Now as usual open the serial port and send a particular character depending upon the quadrant in which the object lies.

So you basically take a snapshot again and again and manipulate that snap. So each image is made of 3 components red, blue and green. Since we are using white light as the object it does not matter which component you choose. But if there is a particular colour that the object has take that particular matrix. Now do the thresholding so that you get only the torch circle on the screen.

Then you remove the noise and coalesce the remaining parts to form a single body.

Then you calculate the centroid and take decision.

image

This is a sample of what the image will look like after thresholding. So as you can see it lies in the middle quadrant.

We had written the code such that it will transmit w,a,s,d,f depending on the quadrant. Do top middle corresponds to w and so on you can figure that yourself.

On the controller side we manipulate the data to control the bot.

I’ll be uploading the video soon. Thank you for reading. Hope this was useful.