Temperature control

Projects General Guidance
1

Hallo,

For my project I need to design a heating plate that keeps its the temperature at 40°C. I was told I have to use Arduino.
My knowledge to programming and Arduino is close to none. So, I need help please.

The idea is to use a MOSFET that I have [IRF520] N channel. to create PID control.
while having a temperature sensor (TMP36) this will detect the temperature of the heating plate and send a feedback to the MOSFET when it exceeds the 40°C.

I have Arduino Nano.

I got no idea how to connect the parts, nor how to write the code!
I found online PID control tutorial but it's different from the connection and the parts that I have.

if you could help me please don't hesitate.

regards

2

No, You don't need an Arduino. Get a thermostate that can be set to the temperature You want, at 40 degrees. When the temperature is below 40 a heater receives power. Above 40 degrees, the thermostate switches off the heater.

3

Railroader:
No, You don't need an Arduino. Get a thermostate that can be set to the temperature You want, at 40 degrees. When the temperature is below 40 a heater receives power. Above 40 degrees, the thermostate switches off the heater.

thank you for your response.
unfortunately, I'm required to use Arduino. Because I also have to maintain this temperature only for 30 minutes and then cooling it a bit down. this heating plate will be a part of a device that works with Arduino.

4

Okey. Search for Arduino + temperature. There You can get ideas about temperature sensors. An Arduino can easily work as a simple thermostate, switch heat on if temperature is below the limit, switch off when reaching target. That gives a certain temperature variation. PID is quite more sofisticated to tune in, not suitable for novice people.
To program a timer, some start up, maintain temp, and cool down, is no problem.
The heateter.... Get a logic MOSFET that handles the voltage and current used for the heater.

5

The first thing you need to do is come up with a schematic including all your components.

A bit of Googling and you should be able to come up with something you can show us.

6

This is fairly simple (for an Arduino project). :wink:

The "trick" if you are a beginner is to start with a simple program (like the Analog Read Serial Example) or a "program outline", and then add one or two lines of code at a time, test-compiling and test-running as you go. That's not quite as simple as it sounds because you can't just start at the top and work down... The compiler needs to see a "complete program".

The other trick with the Arduino is to use print statements and the Serial Monitor (like the Analog Read Serial Example) to show variables, or to show little messages about what the program is doing, etc., so you can "see" what it's doing as you are "developing" the program and/or if it's not behaving as expected.

Also, work on the input & output separately. I'd probably start with temperature measurement.

There are lots of temperature sensors that will work. The analog [u]LM35[/u] ("calibrated" in Centigrade) and LM34 ("calibrated" in Fahrenheit) are probably the easiest to use.

In software, you just need to [u]map()[/u] the raw analog-to-digital reading to temperature. (This will take a little math with ratios... The ADC is reading voltage, but not in units of "Volts". i.e. The reading is proportional to the voltage, so the actual voltage can be measured/calculated. The LM35 datasheet does give Volts, but you can go directly from the raw reading to temperature, or your software can convert to Volts first, if you find that easier or if it makes you "feel better".)

Then you need an [u]if-statement[/u] to turn-on the heat if the temperature is below target and off when it's above target. In the real world, it's common to use a little [u]hysteresis[/u] so it doesn't switch on & off too rapidly, but that's up to you.

temperature of the heating plate

What's powering the heating plate? A MOSFET driver circuit can be used with DC. If it's powered from 120 or 220VAC, [u]this "industrial" type of solid state relay[/u] can be controlled directly from the Arduino, and they are easy to wire-up and easy to mount. (A regular electro-mechanical relay needs a driver circuit, or you can get relay boards with a relay and driver built-in.)

If you wanted to add an LCD display and a temperature adjustment knob/switches, that can be done but your project gets more complicated.

My knowledge to programming and Arduino is close to none. So, I need help please.

How about electronics? Since this is apparently a student project, maybe you an find an electronics student to help. An electronics major (in college) should know enough programming to help with this.