Help me concerning my Arduino Programmable Temperature Controller project

Hi guys,
You all know that it is winter the period of cold, so I decided to make an Arduino Programmable thermostat like W1401 and W109, but this time it will be with an LCD screen with an I2C serial interface for fewer pins, LM35DZ temperature sensor, two 44 fans for heat distribution and 500 ohms resistors with 12v power supply as a source of heat, and a 44 keypad to indicate the adequate temperature for you. But this part of the project is the most dark because I haven't any idea concerning the code. I can make a simple one with a limit of maximum and minimum temperature but you have to change the code whenever you want to change the temperature.
Please, help me solving this issue, I rely on you.

This is a learning forum, but each single issue takes a lot of time to discuss. You are asking for an extended tutorial about how to write a fairly complex piece of code. You can not rely on a forum for that.

Instead, take your existing project, and add one feature at a time, then test and prove it works before moving to the next step. Pick what you think will be the easiest modification. Make a serious attempt to code it yourself, and post it here if you have any problems.

Then, repeat if you like until you have all those features.

12V across a 500Ω resistor would dissipate 0.288 Watts, 248 calories per hour. It would take more than 4 hours to warm 1 liter of water up 1℃. What do you plan to heat with that?

First, reconsider your choice of heating element. Even having a massive array of resistors, that's still pretty jank. I would suggest using an commercial AC-based heating element, and using a relay to control it.

Second, as @aarg said, plan your steps, and build your program in blocks. Break things into module, make block diagrams for them, plot their interactions. Then build the modules one by one, making sure they work by themselves at first, then combining one with the other slowly. Also, plan your pin usage, sometimes they can get messy if you don't plan them well.

Personally, I like to make sure all my input and output elements work first before even thinking about the logic, so, I guess that's where you should start, imo.

JCA34F:
12V across a 500Ω resistor would dissipate 0.288 Watts, 248 calories per hour. It would take more than 4 hours to warm 1 liter of water up 1℃. What do you plan to heat with that?

I can use low value resistors for example a 15 Ohms resistor with rated power of 0.25w would dissipate 9.6 Watts and the result is fire then overheating which produces an acceptable amount of heat with 16 resistors for each fan but we shouldn't risk with 12v across 15 Ohms 1/4 Watts resistor.

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linearity64:
First, reconsider your choice of heating element. Even having a massive array of resistors, that's still pretty jank. I would suggest using an commercial AC-based heating element, and using a relay to control it.

Second, as @aarg said, plan your steps, and build your program in blocks. Break things into module, make block diagrams for them, plot their interactions. Then build the modules one by one, making sure they work by themselves at first, then combining one with the other slowly. Also, plan your pin usage, sometimes they can get messy if you don't plan them well.

Personally, I like to make sure all my input and output elements work first before even thinking about the logic, so, I guess that's where you should start, imo.

Can I use a 12v heating cartridge with the resistor and a pair of 12v tungsten car lamps that produce an acceptable amount of heat ??

@bechir05

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Hi,
What are you trying to keep warm?
What is its size, volume?

Thanks… Tom… :slight_smile:

TomGeorge:
Hi,
What are you trying to keep warm?
What is its size, volume?

Thanks.. Tom.. :slight_smile:

Practically it should be able to warm up a room but it it enough to do that for my desk or the place that I am in let's say 223=12m^3

I think you’ve seriously underestimated the amount of power it would take to heat that space.

Hi guys,
The idea is to make a smart room heater but practically it should be able to heat the volume of 4 to 8 m^3(cubic meters). First, I thought to use low power 1/4w resistors mounted like a radius for a pair of fans with 12v power supply that gets overheated when the power is higher than 0.25 watts and a pair of tungsten 12v car lamps that warm up for an acceptable amount. For example: this type of resistors gets on fire for for 12v across a 15 Ohms 1/4 watts one. But after thinking, I found that it isn’t sufficient.
So please help me concerning this issue giving advice about low cost commercial heaters or even how to make a DIY one myself.
HELP please!

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