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Temperature sensor interfacing using Atmel 89c51
I'm doing a project on Atmel microcontroller.

Hi everyone,

I'm doing a project on Atmel microcontroller.

The aim of the project is to sense the ambient temperature using lm35, digitize the data using adc0804 and then display the temperature on an LCD. When the temperature exceeds a certain threshold display the message and simultaneously activate a buzzer.

Components used are:
lm35 (temperature sensor)
at89c51 (microcontroller)

Source code in 'C'

If you have any information or data or useful links regarding this project please reply.

Thanks in advance. :)

I too need assistance for my project so if get
any information or data or links abt this please mail to my Email ID: ""
send me our Email ID for more details regarding my project.

Thanks in advance. :)
Bye waiting for ur reply. don't forget please.

By Ganesh sharma on 11 February, 2007 - 3:06 pm

We have completed a similar project with the support and guidance of M/s united7 Technologies which have a cute website with all details.One can visit to see thier list of Projects available with them at

I'm SAIRAM from Andhra Pradesh doing the same project which you r doin. But the only diff. is that we should display the output on a PC using serial transmision. It seems u have already completed the project. So plz send information which will be useful for documentation. We already got the output.

So waitin for ur reply..
Plz do reply


I'm also doing a study on Atmel 89c51, and I think your project is good. If you complete your project then tell me how you completed it. Send me your cct diagram and C code at umair_mukhtar2002 @ hotmail. com

When I was a student it was common for some students to ask for help with their assigned projects. But there was never a time when students would be so brazen as to ask for help in a public forum. Wow...!


Jack Eskew - President
Microsmith, Inc.
18401 N. 25th. Ave.
Suite 100
Phoenix, AZ 85023


I want to do the same project. I am an engineering student in Nepal. Could you please send me the required circuit diagram alond with a little bit of explanation on the project

Hello kiranmayi!!

How are you? I read your post on the topic. I'm doing the same project regarding temperature control using LM-35 and the ADC0804 and showing display on the LCD. I am using the same hardware as you are using... so can you please help me in this project? Please, can you share some information regarding this project? I'm a student of MECHATRONIC NUST PAKISTAN. I will be looking forward to your help.

Hi this is Ronics...

I'm doing the same project as you describe. I use At89s51 instead of At89c51 because its programmer can be easily made... and I use adc0808/0809 and lm35. I did it successfully. For further details contact me...

Hello, ive been working on a similar project. ive succeeded in designing the temperature and light sensor but how to interface it to the adc?am using adc0808?please mail id is

Hi kiranmayi,

I'm dona and I was just wondering if you had finished your project? And if so can you help us with our project same as yours? Can you send me your code and circuit diagram?


I'm doing a project on incubator interfacing and designing, and it invloves the interfacing of temperature sensor LM-35 with the atmel 8051 microcontroller and ADC-0804. Can you please help me in this regard as you are doing the very same project?


I am also doing the same project, but we are placing a stepper motor instead of LCD display.

Can you help me in documentation of the project? If you wish to do so please send me a soft copy of your project documentation.

Seeking positive reply from you.

Yours obediently,


I am also doing the same project. I have written the source code in assembly language using keil.
Can you send me the code that you have written in c? I want to check it out. My e mail ID is adharmasingh @ yahoo. co. in
Looking forward to your reply soon.

Thank you.

Hi Rajaraja,

I have read your post and noticed that you have written the source code in assembly language using keil.

Currently I am doing a project that need the same application. Can you send your source code to me so I can make it as reference? Sincerely you could consider this request.

My email is amel036_yippee @ yahoo. com

Thank you.


I am mukunda. I'm doing my final semester of engineering. I am also into the same project as yours. Kindly provide the updates about the project if any to my mail


By sharib ali on 10 April, 2007 - 11:17 am


I am an engineering student. I am trying to do the same project using thermistor, MC AT89C52 and LCD. But I am getting problem with the codes, which I'm writing in assembly language. If you send me your codes, I'm sure it will me a lot.

Thank you,

By pallavichand on 5 July, 2007 - 11:05 pm

Hi kiranmayi,

I want to do the same project, temperature sensor interfacing using Atmel 89c51.

So for that will you plz send me the document, source code and circuit diagram then it's lost to me.

Thanks & Regards,

Do you have any info about the project? I am doing a ToolBox which includes interfacing sensor with 8051microcontroller. Do you have any info about it? How it interfaces, how's the code? Thanks if you could help me.


I am doing same project as you, and I am tiring of searching the net but yet can't find any source of it. Could you kindly help me please?

I will really thank you and appreciate it...

You are all lazy student... did not want to think.

Try the book "The 8051 Microcontroller and embedded systems-using Assembly and C" Second edition by Muhamad Ali Mazidi, Janice Gilliseple Mazidi, Rolin D. Mckinlay.

Ref: Page 404, you have the solution with circuit diagram.

i'm new in this web. but i'm not new in programer.I see your project is cool. you said,you used 89C51,LCD,ADC0804 and LM35. I work in automatic field,i see many manufactors use PTC resistor as a temperature sensor, so why don't you use it?u have to create a constant current so when the temperature raise, the resistor raise so the voltage drop in this resistor raise. The voltage then will be sent to 89C51 as a input signal. it look like very easy,right?It's my opinion. But you can send me your project, i will see it and feed back to you as soon as possible

combination makes you live, division makes you die

I can help you with a temperature sensor made use a microcontroller 89c51. My e-mail is orduzandres02 @ hotmail. com

Hello everyone,

I am doing a project with the 89C51CC01UA Micro, and my project is the control the temp. sensor, refrigeration equipment, CO2 sensor, ethylene sensor and humidity sensor. Is it possible to integrate all these in a single micro? If possible, can anyone help me in this? I will be very thankful.

E-mail ID:



By Taimour Azhar on 31 October, 2007 - 10:19 pm


I'm also doing quite similar task, just the difference is that I have to control a fan instead of buzzer.

I have certain schematics and codes which I can share if you want to, though I'm new to it and just started my project. I'll be thankful if you can help me a little. This is my personal email id, you can contact me here: me. educator @ gmail. com

well the very same thing i m doing it, i m giving the threshold value by keypad and that will display on LCD, if the temperature rises from thresold value then at the output instead of LED, i have attached a fan that will turn ON

By HAREESH.M on 23 April, 2008 - 1:42 am

Hi kiran, glad to meet you. I am also doing same project but using the ASSEMBLY LANGUAGE insted of C LANGUAGE. I have prepared my hardware and software also, but one problem with assembly language I have faced is that we could not represent the floating point. I have total C code for this project, if you need it then mail to me, I will attach to your mail.

hareesh. makesu @ gmail. com

I want to know about temperature sensor interface withAT89C51