The desired result of our setup is to stop the elderly from falling by detecting the angle the walking aid makes with the ground, which will trigger the servo once it reached a specific angle. When the elderly are walking using the walking aid, the servo motor must not be triggered by the elderly when they are picking up the walking aid during walking. Therefore, we experimented with different angles of which the distance sensor makes with the walking aid (the distance measured), and checked the angle the walking aid made with the floor that is needed to trigger the setup. We concluded that 40° is the best way to place the sensor to prevent the elderly from falling.
Placing the distance sensor at 90° (i.e. horizontal to the ground level) is not desirable as measuring the distance straight ahead means detecting all the obstacles in front of the elderly, including people walking in front of them. If we do place the distance sensor at 0°, it would constantly trigger the servo motor, which will be extremely bothersome for the elderly to properly walk. It greatly decreases the accuracy of our design.
Placing the distance sensor at 30° and 35° is not preferable also. From the experiments, the angle needed to trigger the servo is 35° and 30° respectively. At this angle of inclination, the elderly is already falling and the stick will not be able to bear the weight of the elderly and restrain the elderly from falling. It is not effective in preventing the elderly from falling.
At 45°, the angle needed the trigger the setup is 10°. This implies that even when the elderly is walking normally with walking aid (lifting up the walking aid to walk), it will already trigger the setup. Similarly, it will be extremely bothersome for the elderly to walk properly if a stick is constantly sticking out every time he or she is walking.
We have also experimented with placing the distance sensor at a lower position, such as next to the servo motors. However, the distance is too small that the servo motor cannot be triggered. With the limited space at the leg of the walking aid, it would be undesirable for the distance sensor to be placed.
E. Suggestions, limitations and the way forward
There are mainly two limitations of the design.
The first limitation is about the application of sticks used to support the ground may be restricted to common floor materials such as cement and wood only. The sticks may not be applicable to all kinds of floor tiles since grounds of different places may be making use of different floor materials. To deal with this problem, we can add some scrubbing material such as rubbing sandpaper on the surface of the stick to increase its friction with the ground of different materials. At the same time, the sticks may not have enough surface area in contact with the ground to support the weight of the walking aid and the elderly. For this, instead of the currently proposed stick which is designed vertically, we can modify it to become an L-shaped stick so it can support more weight while increasing its surface area touching the ground.
Another limitation is that the design may be too bulky and will affect the appearance of the walking aid. Since the sensor board and batteries will have to be attached to the walking aid, the whole setup may become quite clumsy. As electrical wires will also have to be attached to the sensor board to form a closed circuit, they will have to be hanged from 65 cm (where it connects to the distance sensor) to the rotary sensors at 10 cm placed at the side of the walking aid together with the sensor board in the middle of the aid. To solve the problem, a sensor board which is of much smaller size while retaining all the connecting circuits can be applied. On top of that, a battery may be replaced by using light energy. When the rotary sensors and the distance sensors detect light, they can operate on its own and will not have to rely on the use of a battery. Not only can this reduce the weight and the bulkiness of the walking aid, but it will help save electricity and will become an environmentally-friendly design.
We hope that with improved design as suggested, the walking aid will be able to have a better exterior while providing the best experience for the elderly to prevent them from falling and that fewer accidents of these will occur. If possible, we also hope that the idea will not be limited to walking aids, but will also be available to ages of all people such as for babies of early stage to assist their walking. Besides applying it in child development, we are also hoping that it can be applied in rehabilitation for patients who have had accidents that affect their walking. Our design will surely be helpful in minimizing risks of falling of the patients, which will definitely be beneficial for the recovery of the patients. Above are a few suggestions of how this design of ours can be applied, while it surely can be envisioned in countless ways and in wider aspects. On firm grounds, we believe that our design is able to lower the number of accidents that are related to falling.
F. References
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135440/
2 http://www.cuhk.edu.hk/med/shhcgg/healthyageing/ageing_in_hk_demography.html
3 https://www.pco.gov.hk/psi/rf/Module_on_Falls_in_elderly.pdf
4 https://howtomechatronics.com/tutorials/arduino/rotary-encoder-works-use-arduino/
G. Appendix
The programme code of the logic design for the Arduino is as follows:
#include <Servo.h>
Servo servo1; // create servo object to control a servo Servo servo2;
const int pingPin = 7;
int LED2 = 2; //port for LED Green int LED3 = 3; //port for LED Red
const int buzzer = 4; //buzzer to arduino pin 4 void setup() {
Serial.begin(9600);
servo1.attach(10);
servo2.attach(11); // attaches the servo on pin 11 to the servo object pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(buzzer, OUTPUT); // set buzzer as an output }
void loop() {
long duration, cm; // the distance result in centimeters:
// The PING is triggered by a HIGH pulse of 2 or more microseconds.
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
// The same pin is used to read the signal from the PING. a HIGH // pulse whose duration is the time (in microseconds) from the sending // of the ping to the reception of its echo off of an object.
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH);
// convert the time into a distance
cm = microsecondsToCentimeters(duration);
// the condition for the distance if ( cm > 75) {
servo1.write(00); // sets the servo position according to the scaled value servo2.write(00);
digitalWrite(LED2, HIGH);
digitalWrite(LED3, LOW);
noTone(buzzer); // Stop sound delay(100); // for 0.1 seconds } else if ( cm > 10 && cm < 75) {
servo1.write(140); // sets the servo position according to the scaled value servo2.write(140);
digitalWrite(LED3, HIGH);
digitalWrite(LED2, LOW);
tone(buzzer, 1000); // Send 1KHz sound signal delay(8000); // for 8 seconds
} else {
servo1.write(00); // sets the servo position according to the scaled value servo2.write(00);
digitalWrite(LED2, LOW);
digitalWrite(LED3, LOW);
noTone(buzzer); // Stop sound delay(100);
}
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(100);
} long microsecondsToCentimeters(long microseconds) {
// The speed of sound is 340 m/s or 29 microseconds per centimeter.
// The ping travels out and back, so to find the distance of the // object we take half of the distance travelled.