Week 13 Final Year Project 2

Date: 27 April 2018

Time: 3.00 p.m

Place: Medical Section Level 5


Objectives:

- To design the circuit with sensors as a prototype aid with Led and buzzer notifications in detecting the smoke or leakage gas.

Activities:

- Today, I am designing the circuit for the notifications by using the LED lamp and buzzer when the gas sensor detects the carbon dioxide gas and smoke in the surroundings. It is useful to alert the users when the reading is high at the limit set by light up the LED and sound from the buzzer. There are two LED's that indicate the air quality is good condition and hazardous condition in yellow LED and red LED. When the air quality was hazardous, the led will light up to alert the user and buzzer also sound. The buzzer turns off after air quality back to normal condition with yellow Led light up. 

- The diagram above shows the complete circuit that I designed it to give the alert to the user in monitoring temperature, humidity, and carbon dioxide. There is a buzzer and LED in one complete circuit. While the diagram below, it shows the LED notifications when air quality is high and low. 

- The yellow LED light up to show the air quality is good condition while the LED light up in hazardous condition. This is a good solution to give the alert if the leakage gas or on fire in the hospital ward and buildings. For the future, it can upgrade the system by using the fan to fan out all the gas hazard in the surroundings.

Week 12 Final Year Project 2

Date: 18 April 2018

Time: 3.00 p.m

Place: FYP level 5 room 


Objectives: 

- To test the MQ-135 gas sensor with the smoke from soldering iron and observe the reading as the output. 

Activities:

-  Today, I want to test again the MQ-135 gas sensor to get the accurate value when it detects the carbon dioxide gas and smoke from soldering iron. Before this, this sensor did not get the value because the connection of the sensor (analog pin) was connecting to another pin. So, today the gas sensor is connecting to the analog pin of ESP 8266 nodeMcu. When I was connected the analog pin of the gas sensor to the analog pin of ESP 8266 nodeMcu, there was a reading output in normal condition. Normally, MQ135 is mainly used to detect the concentration of carbon dioxide, alcohol, benzene, NOx, ammonia and other gases in the air. 

- The diagram above shows the smoke from soldering fumes to detect the smoke and carbon dioxide gas by the MQ-135 gas sensor. When the sensor detects the smoke, the output reading was increased as an analog output. It was shown that the connection was successfully correct and the sensor worked properly. The sensitivity of the gas sensor at digital pin can be calibrated by using the potentiometer. I notice that the power LED on the module was glowed and when no gas it detected the output LED will remain turned off meaning the digital output pin will be 0V. 

 

- The diagram was showing above the reading when the smoke and carbon dioxide gas detected by the gas sensor to the surroundings. When there is an increase in polluting gases, the resistance of the gas sensor decreases along with that. These sensors have to be kept on for pre-heating time before I can actually work with it. I read the analog values (0-5V) using a microcontroller, this value will be directly proportional to the concentration of the gas to which the sensor detects.  I can experiment with this values and check how the sensor reacts to different concentration of gas and develop my program accordingly.