Help with my project - Heating and drying device

Hi everyone, I am from Argentina, and got to know Arduino a couple of years ago. Never got into it until now that I bought my first board because I need to work on a project. :o

I customize motorcycles and have a really hard time when it comes to painting the fuel tanks. Some take several layers, others lots of colors and takes quite a long time for the paint to get dry to be able to give a second coat. :confused:

But this nightmare becomes a dream when the tank is heated at 60ºC for 20 minutes. And here is where I need your help. :slight_smile:

I crafted a heating and drying machine which uses quartz lamps as a heating source. 2400 watts of heating power! really useful and quite handy but quite a mess to get the right temperature constantly for it to work. Thats when Arduino hit me.

I would like to make a controller with Arduino, this are my materials

  • MEGA 2650 board
  • TFT_320QVT_9341 touch screen
  • Elecfreaks TFT LCD Mega Shield V2.2
  • a 2 relay module
  • one Thermostat

I wish to make a system where Arduino asks for the working temperature between 40ºC and 80ºC and the time during which the "oven" needs to keep the temperature. Once this is set, the Arduino should show me a Screen with the actual temperature inside the oven and the time left for the process to complete.

It should also let me pre-heat the oven prior putting the fuel tank inside to optimize time.

Thanks a lot! Hope someone can help me!

A better way to do the input is a few robust water/dirt proof push buttons rather than a sensitive touch screen. Two for temperature up/down, two for time up/down, one start, one stop (if you want to stop before time is up - can be combined with the start button for five total). These buttons can continue to work during operation so you can increase/decrease the temperature setpoint and baking time as it happens if you feel the need.

A simple 1602 LCD is enough for this application output (all you want is a countdown timer, temperature set and temperature actual), for Arduino you can take a micro, you don't need a mega for this.

With this amount of power you probably shouldn't switch it all at once, but ideally a near constant scale. You're switching 11A assuming 220V AC, so you can use a triac instead of relays, and basically create a dimmer. That, combined with PID control, will give you much better heat control than switching on and off. You will want full power when pre-heating, then down to maybe 20-40% to maintain temperature, or even less if you have proper insulation (also a good way to make temperature more stable) and lower temperature (like 40° which may be just 15° above ambient).

How is your ventilation? As it's paint I expect lots of VOCs so relays are an extra risk as they spark (and they will big time with this kind of currents). An explosion may ruin the paint job, and you wouldn't want that to happen.

Guess I oversized everything in my project… Unfortunately I already bought everything. Guess I will have to find some other way of doing it! Thanks for your help

I have such project made.
It based on :
Arduino mega + ethernet shield = web server
ds18b20 thermosensor.
The goal:

The results:

interface - buttons:

interface - settings:

The device in box:

can be controlled from phone or any PC:

I can translate it to english easy.

one project for all occasions?

Yes, I mean… It’s the control unit for the unit. The problem is that I followed the tutorial on Internet by
Dejan Nedelkovski from and tried to make that code work. but my screen shows just a white screen, nothing appears. Tried changing the driver and the pin settings and nothing came out. Always the same pale color.

Its quite simple I guess. the screen turns on, set the temperature, then the time. Ones that is ser you have 2 buttons. Pre heat and start. The start button starts a countdown that when reaches zero, it turns off the heaters. Both data sources should be saved in order to be able to execute the heating device without setting it up every time…

But can’t find a tutorial that I can try. Tried making a GUI, no result cause drivers don’t work with my screen. By the way (it just says TFT_320QVT_9341, no idea who the manufacturar is)

I'm not sure this is something I would bother building. Temperature is the most commonly controlled process variable and there are many temperature profile controllers available cheaply that would do what you ask. I couldn't find one quickly (profile control), but here's a regular temperature controller. Pair it with a timer and you're done:

There was a problem with the library, I guess I was using the wrong driver for my screen. I could finally got it working by using the ILI9341_16 driver and now my GUI works perfectly... Now I will star to put in the code for the DS18B20 sensor and the 2 relay module one for each heating device.

I know there are ways to make it more simple... But as I am not the online operating the device, the screen contains the instructions on how to make it work. And it is quite flexible, almost any operation between 0º and 100º...

Thank you all for the suggestions and the ideas. I guess I will take a tour on the other sections of the forum to find the right info for what comes next!!!