What materials do you need to complete the popcorn machine in family barn?

Please provide me with more context! I need more information to understand what you mean by "popcorn machine in family barn".

For example, are you asking:

* What materials are needed to build a popcorn machine? If so, are you looking for a homemade, simple version, or a more complex, professional-grade machine?

* What materials are needed to use a popcorn machine in a family barn? In this case, I'd need to know if you have an existing popcorn machine and what kind of space you have in the barn.

* Is there a specific recipe you want to use for the popcorn?

Once you give me more details, I can give you a more helpful and accurate answer!