How to know a Database(Table) changed if I only have dbreader role(read permission) ?

Question

My application is a sub-application which could know a database(table) changed by main application through SqlTableDependency
(https://github.com/christiandelbianco) 

When I was using SqlTableDependency, I had sysadmin role which can create triger, contract, message, queue, service broker, procedure but now I only have dbreader role(read permisiion). 

What is best solution for this limited situation? 

Or what if the main application creates a .txt file in a folder whenever the database(table) is changed, how can I utilize the creation of a .txt file ? 

Thank you so much !