Keeping a Mini from locking; but want it to sleep?

So, I know how to keep an iPad mini from going to sleep and locking... which means it always stays illuminated.

Is a way to keep it from locking but will allow the screen to go dark after a period of time.

I'm using them as control panels for a home automation system.

I know it sounds really whiney but when you are using a device to control lights in a room and you have a choice of either leaving the screen illuminated constantly (which for instance in a bedroom is a problem) or having to perform at minimum 3 steps to turn your lights on by waking up, unlocking and then touching a light button it's kind of a big deal for older clients of mine.

I'm currently specifying iPad mini 2 but i the question is really for any of the models... if there is one that will do this or some kind of a hack that allows it.