PTC Heater Control

[kadakisama]

Tried doing it earlier today.
Didn't use a breadboard because i was scared of the large amount of current that would go through it and that i would end up starting a fire again.

anyway this is the schematic i followed

And the code:

#define HEATER_PIN 25


void setup() {
  pinMode(HEATER_PIN, OUTPUT);
  digitalWrite(HEATER_PIN, LOW); // Heater off
}

void loop() {
  digitalWrite(HEATER_PIN, HIGH); // Heater on
  delay(5000);
  digitalWrite(HEATER_PIN, LOW);  // Heater off
  delay(5000);
}

No changes. is there a way to confirm im actually doing the right thing or if there's something wrong

[TomGeorge]

@kadakisama

No changes. is there a way to confirm im actually doing the right thing or if there's something wrong

Do you have a DMM? (Digital MultiMeter)

If so you should be able to measure the 5s ON/OFF signal coming out of pin 25.

If so you should be able to measure the 5s ON/OFF signal on the Drian of the MOSFET.

How much current do you aim to run through the PTC?

The 1K resistor in series with the PTC will limit the current to 12/ 1000 = 12 mA.

P = V x I = 12 x .012 = 0.14 Watts.

Can you please post link to specs/data of the PTC?

Tom....

[kadakisama]

I plan to pass 15A through the Heater to start it up, it will stabilise to 10A after a few seconds. Does that mean I should remove the resistor?

That was the only file I received from the company. I do have a DMM and i will measure the signal

[TomGeorge]

Hi, @kadakisama

Can you please tell us your electronics, programming, arduino, hardware experience?

Do you know how to use Ohms Law?

What is your 12V power supply?

Tom....

[kadakisama]

i am at most a beginner in electronics, I have only done very basic programs in python and arduino (C++) as for hardware, also no experience. i did however learn ohms law (V = IR). I haven't really applied it before now.
My 12V power supply (12V 30A DC Power Supply Driver - Universal Regulated Nigeria | Ubuy) is similar to the one in this picture. I got mine from an open market.

[TomGeorge]

Hi, @kadakisama

Okay, leave the 1K in the circuit and do the measurements I recommended.

The wiring you have will not be able to carry the 15A your PTC will draw if you remove the 1K.

Tom....

[kadakisama]

did you mean 5v?
I put the black probe on the ground of the esp32 and the red on the pin 25, i moved the red probe across the resistor to the gate of the mosfet also 3.3v.
i put the black probe on the -12v coming from the power supply and the drain 8.5v, and after the resistor it was 12v, it remained at 12v after the diode, the positive leg and the negative leg (of the terminal the heater is connected to).

[jim-p]

@kadakisama

or if there's something wrong

Yes there is.
It's already been determined that the IRLZ44N will burn up.
So why are you trying to use it?

See post #39

I would try to make the BTS driver work

[jim-p]

@kadakisama

I did this, using an arduino UNO a

Seems like you changed horses midstream!

There is a BIG difference between an UNO and the ESP32
From the very beginning you said you were using an ESP32.

So exactly what tests were made with an Uno and which with an ESP32?

All of my suggestions assumed you were using an ESP32 and will NOT work on an UNO

Which board do you actually plan to use?

[kadakisama]

Ohhh. It seemed I didn't understand the post (the resistance seemed quite low).
Alright thank you very much.

[kadakisama]

that was the only one I tried with an Arduino UNO. All the test were performed with the ESP32 including that one. I used the Arduino so I could use the onboard LED.

I plan to use the ESP32 with this project

[jim-p]

@kadakisama

It seemed I didn't understand the post

Well you should have said so, no problem.
I think the simplist solution for you would be to find a 20A (or more) relay that can work with the ESP32 3.3V I/O

[jim-p]

Buy a heavy duty 12V relay module like this:

HiLetgo 2pcs 5V 30A One Channel Relay Module Optocoupler Isolation High and Low...

Connect like this with transistor

[kadakisama]

This?

It's 5v 30a

(attachments)

[jim-p]

@kadakisama

This

Does it say 12V and LOW level trigger?

[kadakisama]

hello again
it is a 5v 30a relay.
and from what i understand from the datasheet (https://files.seeedstudio.com/wiki/Grove-SPDT_Relay_30A/res/SLA-05VDC-SL-C_Datasheet.pdf), it has a contact voltage of up to 30v meaning it can handle the heater. and it has the option of low or high-level trigger via jumpers

I got it by the way, a 4 channel one since that was the only one available on short notice, and i managed to get the arduino turn the heater on and off.

THANK YOU VERY MUCH

I will add the transistor the next time I try it.

[jim-p]

@kadakisama

it is a 5v 30a relay.

So now you need a 12V supply for the heater and a 5V supply for the relay. I was trying to simplify things by using a 12V relay so you only needed a 12V supply.

[kadakisama]

there were no 12v relay modules. I already have a buck converter so i used that to step down the voltage to power the relay.

[jim-p]

Glad you now have it working
Have a nice day!

[kadakisama]

Thank you very much everyone for your help.