Try to decide PID vs SPI to control a heater panel(220v AC)

Hi everyone.
I try to find out what is better for me to start my project. I have heater panels in my home (like this https://www.screwfix.com/p/eezi-heat-wall-mounted-panel-heater-400w/6779h) and i want to save energy. So I saw that the PID library is suitable for this project. I saw also SPI but .....i don't know.
The biggest problem for me is to understand if i have to use NPN or Digital potentiometer for this job. I will use Arduino or wemos d1.
Any help will be great !
Thnx.

PID and SPI are not alternatves.

PID is a system for working out the value to use to control something.

SPI is a system of communication.

...R

This is a mains heater, so you need an opto-isolated SSR or similar to switch it.

Furthermore it already has a mechanical thermostat for controlling it - I presume you want to remotely
control it (ie set thermostat to max and switch power into the panel externally?)

The biggest problem for me is to understand if i have to use NPN or Digital potentiometer for this job.

Neither seem appropriate. Since mains appliances run at lethal voltages, I would suggest
doing more research about how to safely control mains appliances. A SSR designed
for mains is basically like driving an opto-isolator, which is an LED electrically.

Mechanical relays are also possible, but are more complex to drive (the NPN might then be
used to drive the relay).

Ok i understand. But is SSR relay able to adjust the energy flow like a digital potentiometer?

hwa_rang098tkd:
Ok i understand. But is SSR relay able to adjust the energy flow like a digital potentiometer?

No, but you certainly wouldn't want to control a heater that way, because using a potentiometer
in series with a 400W heater would require a potentiometer rated at 100W.

You turn it on and off to control average power, just like the mechanical thermostat does.

Thx . I think about it