Temperature Display System

Today we are going to talk about how to make a Temperature Display System. The special feature of this is that you can turn this system on/off from anywhere in the world with your 4n. Also, the main feature is that if the temperature rises above 100 degrees Celsius, you will be notified by a message. We can also display the temperature on an LCD display. Okay, let's see how to do this.

I said earlier that this post is brought using the LM35 Temperature Sensor. But while making this tutorial, that sensor got burnt.. So that's why I used MX6675 K-Type Thermocouple Sensor for this... Ok, let's see what we need to fix this...

1) Arduino Uno :- - Rs.970/=

2) SIM900A Module :- - Rs.3460/=

3) MAX6675 Module K Type Thermocouple Sensor * 1 :- - Rs.910/=

4) 20*4 LCD Display :- - Rs.790/=

5) I2C Adapter :- - Rs.195/=

6) Jumper Wires

Briefly about these items...

You already know about Arduino Uno. That's why I'm not going to say names about it..

If we talk about the MAX6675 K-type Thermocouple Sensor, we can use this sensor to measure a temperature from 0 degrees Celsius to 1024 degrees Celsius.

Also, this system is connected with our mobile phone through the GSM module.

We display the temperature at that time through the LCD display.

Also, you can reduce the amount of wire coming from the display to the Arduino board by using the I2C adapter.

Okay, let's first see how to read the temperature from the thermocouple sensor. For that, connect the sensor with the Arduino board as shown in the image below and try uploading the code below. Although the Max6675 Module was connected to the D8, D9, D10 pins in the image, I configured the Pins in the code.

Max6675 Arduino

GND GND

VCC 5V

SCK D6

CS D5

SO D4

The code is explained in the comments in the code. We need a special library for this.

Max6675 Library :- ...

Arduino Code :- ...

Next, we will see how to use the 20*04 LCD Display with the Arduino Board through the I2C Adapter. For that, connect the display with the Arduino board as shown in the image below and try uploading the code below. We need a special library for this too.

Liquidcrystal_I2c Library :- ...

Arduino Code :- ...

Now let's see how to display custom characters on this LCD display. In this, the pixel 40 inside the cell in the LCD display is controlled separately.

This one cell has 5 pixels in length and 8 pixels in height. So we need to address 8 lines in this Pixel 5. Think like this. This Pixel 40 should be turned on as Pixel "1" and off as Pixel "0", we can address it as below.

11111 - 0x1f

01111 - 0xf

00111 - 0x7

00011 - 0x3

00001 - 0x1

00000 - 0x0

10000 - 0x10

11000 - 0x18

11100 - 0x1c

11110 - 0x1e

That means when you write the pixels you want as a bit pattern. That means we can write the 5th bit, convert the Binary value into a Hexadecimal value and add the part called 0x in front of the Hexadecimal value to create the Address.

Example Arduino Code :- ...

OK, let's check our GSM module next. Check this post for that. I did one a while ago.

GSM :- ...

One thing to remember here is that it is not enough to give power to the GSM Module that we use here from the Arduino board. So you have to use a power like 5V 2A. Also, connect the GSM Module with the Arduino Board as shown in the image below.

Ok then let's start our project. After connecting the device as well as the sensor to the Arduino board, upload this code. Explain the code in the comment of the code.

Code :- ...

So in this case, when you first send an SMS saying "On" to the GSM Module from your 4n, this system will turn on. At that time, an SMS will be sent to your 4n from the GSM Module that the system has been turned on. After that, the temperature at that time will be displayed on the LCD display. Meanwhile, if the temperature rises above 100 celsius, you will be notified of the increased temperature through an SMS. After that, when you send an SMS saying "Ok", the system will continue again. Also, if you send an SMS saying "Off", the system will be turned off and your 4n will be notified by SMS.

Also, another special feature of this system is that when the system is on, even after a power cut, the system remains in the on state. Also, if there is a power loss when the system is in the off state, the system is in the off state even when it is turned back on. That means the current state of our system is saved in an EEPROM. Something in this EEPROM will not be erased when the power is lost.