Digital Thermometer

Digital Thermometer


LCDs facinate me very much. The second thing I did with my Arduino and the 16×2 LCD was to hook it up as per this schematic and try to say hi :)

Then I used the same logic to display the temperature.

Things used for this project are

    Arduino UNO
    16×2 Hitachi compatible LCD
    LM35 Temperature sensor

The LM35 and LCD was wired as shown in the figure.

The major challenge faced during this project was writing the float temperature to LCD. There seems to be some issue with converting float to string in Arduino. After a lot of search I stumbled across dtostrf(). This funciton converts any floating boint number to a string of difined length with defined precision in a predifined buffer which can be printed on the LCD via LiquidCrystal library’s lcd.print().

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sandeep_sandee's picture

digital termometer

 i want kow the code to embedded in the arduino board

`````````````````````sandeep Rockzzzzzzzzzzzzzzzzzzzzzzz````````````````````````````````````````

THUNDER N's picture

code for the digital thermometer

did u ever receive the code? if u did, then please tell me!

kd5aj's picture

LCD pin use

hey guys.. I have found that it takes a little thought to make sure you are not using pins on the arduino for the LCD display that match up with a shield or other attached bus or component. when i was playing with the ethernet shield for example, i had to stay away from pins 4, 10, 11, 12 for the lcd because the ethernet shield was using those pins.. the entire program worked, however, when it was to print out the IP address, the LCD and ethernet shield conflicted giving me gibberish!! ... Hard lesson learned.. about 20 hours of "OMG why is this doing this...." hehehe




nik-mod's picture

Pin use


 thanks that would explain why I got the gibberish that I got when i tried it out.

When my hand heals (busted left thumb) I will get on it .


I NEVER realised how we are so reliant on out thumbs until it is in a cast !

doing up your pants is a nightmare one handed LoL

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sandeep_sandee's picture

i didn't get how it works can

i didn't get how it works can you explain me in a correct way how it works.......................,

`````````````````````sandeep Rockzzzzzzzzzzzzzzzzzzzzzzz````````````````````````````````````````

mtaram's picture

Welcome Nik

It took me a whole day to figure this out. I have been out of touch of coding since last 10 years. This has been an awesome experience.

MtaraM (aka Utkarsh)

Solution Architect by profession, Engineer by thought.

nik-mod's picture

Hi M,  I will not embarress

Hi M,

 I will not embarress myself by telling you how long i fiddled with it and failed :-{

I last did coding with Pascal, C, C++ and Basic & BBC Basic did my Uni 3rd year project on a siderial time calculator for yahtsmen, now all they need is a cell phone and gps enabledd. Back then i designed a  receiver for atom clock broadcast signals coupled to a laptop & my software.. Progress ......

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mtaram's picture


This sounds so awesome. :) You sure do have a lot of experience as hand. I too have learned a lot from failures and it helps a lot to read about the stuff that is being worked on.

I wanted to do all this as a kid but that time it was all too comlex and too expensive here in India. Now that I have a awesom job and more than that a lot of time for these things I am on it.

Its been so long that I have been onto a forum. I lost the touch when I went back to college for Advanced studies in NW and IT infra.


MtaraM (aka Utkarsh)

Solution Architect by profession, Engineer by thought.

nik-mod's picture

Floating point


 well found i had tried it with my Arduino with a spare LCD I had from a computer where it read out the boot process for a Headless server. worked fine with the computer but as you found gave me gibberish display on the Arduino. I thought it was just incompatibility of hardware not a software glitch.


Thanks for posting

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