University Project

Hello Folks, My name’s Marcio I’m a Computer Engennering Student.
So, before are you asking my about my course teachers, university teachers are shit and they think that we are genies.
My teacher of eletronic set a project to delivery but never explain how about make this, he do not explain how to project the circuit and here I am looking for some help.

So this project apparently are simple but I do not understand how to inicialize.

I need an Arduino R3, an Operational Amplificator and a LM35 to Turn (ON/OF) a cooler (or motor) if a especific temperature increase a lot, I’ll set this temperature at 50º Celsius, I know that 1ºc at lm35 is equal a 0,1mV and maybe I’ll need to control using a tension divisor (like a potenciometer)

My doubt is about connection between components I’ll use Fritzing or Protheus to simulate after put on protoboard, very help is welcome

ps.: arduino’s code I will sent after for analysis/comments

The project is reasonable simple. You need to use the op amp to amplify the voltage from the lm35 to get a range between 0 and 5V for an analog input to the arduino. I’d probably use something like an lm324 single supply op amp running from 5 volts. Your control point pot needs to be between 0 and 5 volts in to a second analog input on the arduino and from there it is a simple matter of software to read the analog input from the lm35 and the pot and decide whether or not to turn on the controller. If you are intending to drive the motor, you probably need a motor driver of some kind to provide enough current for the motor. You may want to search in the projects section of this web site for a similar project that would give you some ideas.


Hey, Peter thank you to answer me so faster.
My teacher spoke same thing about 0-5v Control, but I dont know how to make, because I really want to know project and make wire conections, do you have some way to Help me understand the wire conections? And project wire conections?

While I could make this circuit for you, you wouldn’t learn anything from it if I did. Basically you have the lm35 which outputs about 10millivolts per degree so you need to scale that output over the temp range you are interested in (via the op amp as an amplifier) to produce an output between 0 and 5 volts for the temp range of interest. That output goes in to one of the arduino’s analog inputs. The pot between 0 and 5 volts goes in to another analog input. The program reads those 2 analog values via the A/D in the arduino. Your program reads the voltage from the lm35 to figure out what the temperature is and reads the value from the pot to see whether the temp is above or below the set point and turns on the motor if necessary.


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