Now I want to use Arduino as an PLC to setup an industrial control system to drive something like motor or solenoid valve, or read the digital input from proximity switch sensor or photoelectric switch sensor. Unfortunately,most of these industrial sensors and motors operate at voltage over 5 Volt(24V 12V).
Output: It's easy to use relay or power MOSFET like IRFZ44N or transistor to drive the componenet operating over 5V;
Input: I don't have any idea to read the 5V above sensors from arduino. Is it need to use sth like voltage regulators ic 7812,7805 to convert 12v,24v digital input to 5v digital input , then read by arduino??? , and how about analog sensor operating above 5V??????
I had googled little bits about "voltage divider" . It's seem that the simplest voltage divider is resistors voltage divier .
12V(input)
|
R1
|
---------5V(output)
|
R2
|
GND
If we need to convert 12V to 5V .
Vout=(R2/(R1+R2))*Vin
5V=(R2/(R1+R2))*12V
So R1:R2= 7:5
Does it right ??? If i use this to convert downward the 12v to 5v, will there any heatsink problem to Resistor???
If you use suitable values there will be no heat issues with even the tiniest of resistors. A voltage divider is a ratio of values, if you use values in the 1-10 kiloohm range it would be OK to feed an arduino input. I suggest you get a little electrical theory under your belt before you start on a complex project, that way when it doesn't work as expected you'll know where to start looking.