I'm kinda new so.... Does anyone have an idea how I can make a wireless 6-24v motor speed controller? Is Arduino the best (and cheapest) option? or is there an other better and/or cheaper option??
I haven't accuired a specific motor yet. I am still doing research.
The volts is less important than the amps and power. How much power do you need? That will help you select a motor, then that will help you select a motor driver.
Depending on exactly what you mean by “wireless”, you could possibly do this with a conventional remote control. An Arduino is only necessary if you need it to make some decisions on its own - for example stop the motor when it has moved the correct distance.