Is this possible?

First of all hello everyone,first post here,thank you for taking time to read about my thoughts.
I searched the forum and I suppose that this is the right place to post,I might be wrong :slight_smile:
So I will try to give you an example.
I would like to use a tablet to change the speed of a fan.
(This is not what I want to do but if you answer on this example I will be on the right way to search it further. )
First of all it doesn't have to be remotely, I guess that all it needs to be done is an interface on the tablet with scale from 1 to 4 plus 0, so a digital signal that needs to be turned into analog to open or close a circuit on the fan.
I don't want a guide on how to do this exact thing obviously,I would appreciate a lot something to start with..
First thoughts on how it can be done?
Keywords?
A guide with someone that did something similar?
(I am not lazy to search for it myself but I can't really find the words to do it)
Thank you in advance for your time especially if you answered.

It completely possible. Fan usually use DC motor (see Arduino - motor), which can be controlled the speed. You can connect Tablet to Arduino via Bluetooth, WiFi ...
if you just want to simple ON/OFF control, you can refer to Arduino controls Fan tutorial

If you want your tablet to communicate with an Arduino I would suggest Bluetooth (if your tablet has Bluetooth).
On the Arduino you would have, say, an HC05 Bluetooth module. An app on the tablet like Serial Bluetooth Termial (available in the Playstore) can connect with the Bluetooth module on the Arduino and send and receive data. Then the Arduino can control the fan.

More specific help can be provided if you provide more specific requirements.

If you ask a dozen Arduino hobbyists how they would control a fan from a tablet, you will get twelve different replies. All valid.

My go-to protocol is MQTT over WiFi. (Just to give you more reading assignments).

candoattitudegr:
I would like to use a tablet to change the speed of a fan.
(This is not what I want to do but if you answer on this example I will be on the right way to search it further. )

A more general way of describing this is that a program on the tablet sends a message to a program on the Arduino and the Arduino does something in response to that message. If necessary the Arduino could also send messages to the program on the tablet.

This means that there are three separate pieces that need to work together.

The program on the tablet needs to be able to take user input and send a suitable message. That could be an off-the-shelf program (as already mentioned) or something you create yourself.

Then there needs to be a means for the tablet to communicate with the Arduino - bluetooth has been suggested but there are other options.

Finally there must be an Arduino program that is designed to make sense of the messages that the tablet sends and which can (for example) do whatever is needed to turn the fan on or off (perhaps by switching a relay on and off).

I have no experience of it myself but you might want to investigate MIT AppInventor for creating the program on the tablet.

...R

Google blynk arduino

What is needed is to have your Arduino talk to a transceiver of some kind.
Bluetooth, Wifi, RF, etc

Have that transceiver talk to a another transceiver

Then that transceiver communicate in some way possibly another transceiver pair ( wifi) to your tablet.

As a note an esp8266 could be a one device solution. Lots of tutorials for what you ask