Timer Interrupt

Using Arduino Programming Questions
1

I am using arduino UNo board and i am trying to build on delay timer .

I have 2 pots 10k one pot for time Range selection and another for Scaling section.

Time range
1s 10s 1M 10M 1H 10H

Time Scale
0.1 0. 3 0.5 0.7 0.9 1

using 2 pot i could able to get value using analog read ports.

since i dont have real clock, I wanted to use timer interrupt for application . Timing may be no accurate but i could see the time almost equal.

if my pot Time range= 1s Time scale =0.1 The relay should turn on 1S0.1=0.1s
Time range= 10s Time scale =0.1 The relay should turn on 10S0.1=1s

Can someone guide me how i can proceed further

2

since i dont have real clock, I wanted to use timer interrupt for application . Timing may be no accurate but i could see the time almost equal.

The Arduino IDE has the millis() function so you don't need to use timer and interrupts yourself.

3