Week 7 - Journal

Have you EVER been to a production line or a workshop where several rotating machines and tools are there? If yes, you, surely, saw many of caution signs here and there for safety instruction! One of the most common safety signs is the one tells you or the operator to keep a safe distance away from a rotating machine, but... what if one violates this safety instructions?

Here is the automation role!

In the first part of this assignment I'll show you a smart protection system that halts dangerous rotating machine operation when individuals approach the machine in a non safe way ( beyond the safe distance).

Not only personal safety precautions are essential, but also those of machines are crucial as well. The second part of the assignment will demonstrate a smart cooling system that is enabled when system temperature reaches a certain preset level.

I used the ultrasonic sensor to detect if an object or a body is approaching the rotating machine unsafely, and if yes, the buzzer will be activated and the machine (DC motor) will be turned off. The machine will not operate as well as buzzer won't be turned off until there is no object/body within the safe distance from the machine (where ultrasonic sensor is mounted). For demonstrating this concept, I determined 20 cm. as a safe distance.

Besides, and for the sake of machine protection, I used the DC fan to represent the cooling system which will be activated upon a signal sent by the LM35 (Temp. sensor). I set 25 C as the temperature level to activate the machine cooling system.

And there is the question....how ultrasonic sensor works?

Circuit simulation on Tinker CAD can be viewed from the video below 😄

You might notice that temperature range for DC fan activation is not accurate as in the code; this is due to that Temperature sensor in TinkerCAD is (TMP 36) which has different settings compared to the one used in the real circuit simulation (LM35).

The last two photos above show the flowcharts for the two circuits programming. After writing the code, I performed the compiling check in Arduino IDE and here is the code lines:

// Industrial and Occupational Safety

int trig = 9;

int echo = 10;

int buzzer = 13;

long elapsed_time;

long distance; // distance form a machine with dangerous rotating parts.

// Machine safety - Cooling System Automatic Response.

int val;

int Relay1=7; // for cooling system activation

int Relay2=6; // for machine operation ON/OFF control

void setup() {

pinMode (trig, OUTPUT);

pinMode (echo, INPUT);

pinMode (buzzer, OUTPUT);

pinMode (A0,INPUT);

pinMode (Relay1,OUTPUT);

pinMode (Relay2,OUTPUT);

Serial.begin(9600);

}

// Personnel safety - Always keep a safe distance from rotating machines

void loop() {

digitalWrite(trig, LOW);

delayMicroseconds(2);

digitalWrite(trig, HIGH);

delayMicroseconds(10);

digitalWrite(trig, LOW);

elapsed_time =pulseIn(echo,HIGH);

distance = elapsed_time/29/2; // cm

Serial.print("Distance: ");

Serial.print('\t');

Serial.print(distance);

Serial.print('\t');

Serial.print(" cm");

Serial.print('\t');

if(distance <20) {

digitalWrite(buzzer,HIGH);

digitalWrite(Relay2,LOW);

}

else

{digitalWrite(buzzer,LOW);

digitalWrite(Relay2,HIGH);

}

// Machine safety - Cooling System Automatic Activation

val= analogRead (A0);

float mv= (val/1024.0)*5000;

float cel= mv/10;

Serial.print("Temp= ");

Serial.print('\t');

Serial.print(cel);

Serial.print('\t');

Serial.print("*C");

Serial.println();

if (cel>25){

digitalWrite (Relay1,HIGH);}

else

{digitalWrite (Relay1,LOW);}

}

Afterwards, I started to place all circuit components in a breadboard enclosure and tested the circuit and ensured that it worked!

I participated with Ghazaly and Doaa in the MOW and EOW sessions practice respectively. All three of us, especially me, benefited a lot from the group work and shared the ideas how to correctly approach the tasks from planning, components wiring, coding, and troubleshooting! I can specify that during the EOW session, I had the chance to learn how to use a slide switch to choose between two modes of operation (Manual / Automatic) using Arduino IDE coding with the right wiring of components😄

I was quite confused with the 'Relay' module; how it works and how it's connected with Arduino and other components in the circuit. With the kind help of Esraa and Sherif during the EOW (Saturday) session, I managed to understand and use the relay module correctly to power a smart home circuit components (Fan and light bulb)😄