How to create oscillator for custom indicator?

 

I'm hoping someone knows of code thats already out there....

I have a custom indicator who's values range from -10 to 10, but the change may take a year...

I would like to create an oscillator that shows a value from -1 to 1 every 90 days.

ie: if data for last 90 days high is 5 and low is -6, then oscillator reads 1 when data is at 5 and -1 when data is at -6 etc

I'm hoping that there is some way to write an oscillator that I could use "apply to first indicators data".

Thanks,
Matt

 
My best guess so far is to use iCustom to create the oscillator form the indicator...