What is your experience of using 6 MW Apps? Do you use step count based ones or GPS based? How do they relate to the formal ATS 6 minute hall walk test?
I have no experience of using 6 MW Apps but If you need step count or/and GPS, I suggest you this article that I found when I was working with accelerometers.
javascript:"Novel algorithm for a smartphone-based 6-minute walk test application: algorithm, application development, and evaluation" by Nicole A Capela, Edward D Lemaire, and Natalie Baddour (2015).