I don't know in which country you will install that ATM, but at first I would check the legal background of it.
Do you need to obtain special licences for installing and operating the ATM but as it would work with real fiat notes it's really possible that you have to, but you should check it.
If the legal background is clear after you can start thinking about building the ATM. Or you can check if there's a second hand ATM available for you somewhere to start with... maybe it's easier to have a working one and see how it works than to start it from scratch...