Are there laws preventing someone from collecting data not connected to a sanctioned research project?
Since you ask for legal advice, only a lawyer in the country in which you intend to do the research can really answer your question with authority. 

However, the usual reason that it is useful to be part of a University or Firm when doing research, is that they normally employ lawyers that can answer these questions. Affiliation isn't essential, but good advice is. A university may (will in the US) have an office that will help assure that you don't overstep legal or ethical boundaries. 

I would try to visit a local research institution and see if they can give you guidance on your proposal. There are some things you aren't allowed to ask human subjects and some restrictions on data use, etc., but these differ by country. Perhaps a local university publishes its guidelines and they may be available to you even when unaffiliated. 

Different countries also are likely to have a bureau whose purpose is to publish legal and ethical advice to researchers. A local search may turn up the information you need. 

But proceed cautiously in any research that involves human subjects in any way.