Arduino Thermometer + LCD I2C




I've decided to provide a funny Arduino concept thermometer in case its the middle of the night, pharmacies are not working, you are not feeling well and you want to check your body temperature. If you have Arduino by your side, this is a life saver!

Components you will need:

Arduino Uno/Nano, whatever

Some breadboard wires

A 10K resistor

A thermistor ( I got it from my first Arduino kit)

If you want to make it look more fancy, you can add:


I2C LCD adapter

Step 1: Connecting the Components

On the pictures above, you can see how you should connect the components on the board if you want to try if the code is working. When you are satisfied, you can connect a batch of wires together as seen on the last photo to lenghten the thermistor connection

Step 2: I2C LCD Tutorial

If you want to display your results on something fancier than a Serial Monitor, here is a small I2C LCD tutorial.

If you want to learn more about I2C, google it, it is very useful and if your components support I2C, you can decrease the number of wires many times.

You will need the regular LCD and the I2C LCD module. You can buy them separately, or you can buy them together like on this link:

Solder the two pieces together as shown on the pictures above.

If you are using Uno/Nano, the SDA and SCL pins are A4 and A5 respectively. Connect the pins on the LCD I2C module to the ones on the Arduino.

Step 3: The Code

In the main code you will have to adjust the values of your thermistor nominal resistance or the beta coefficient if you are getting some strange results. Be aware that the current settings are calibrated for the normal human temperature of around 35-40 degrees Celsius so if you would try to measure your room's temperature you would probably get some bad results.

Since every I2C device has its own address and it may not be the one I have included in my code, I have attached another program which will find the address of your device if you connect it like said before.

If you dont want to use I2C LCD, just edit all the LCD parts from the main code and just use the regular Serial Monitor instead :)

Step 4: The End

I hope you liked the instructable and if you have any questions feel free to ask them in the comments and I will try to answer them as soon as possible.

Until the next one!



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    8 Discussions


    Reply 2 years ago

    More than likely it is a 10kOhm NTC type thermistor. NTC stands for "Negative Temperature Coefficient" meaning as the temperature of the thermistor increases, the resistance of the decreases. Also, 10kOhm is the resistance of the thermistor at 25 deg. Celcius. This type of thermistor is the most common.


    Reply 2 years ago

    I got it with my first Arduino beginners kit, but I'm sure ebay is full of them


    Reply 2 years ago

    In the specification of the Arduino is not specified the model of the thermistor?


    3 years ago

    cool project!