The project involves three stages. First, a prototype activity sensor will be validated. Second, a smartphone app (iMove) will be developed and co-designed . Lastly, the developed app and activity sensor will be used to conduct a micro-randomized trial (MRT) to reduce sedentary behaviour and promote physical activity among adults with type 2 diabetes. Individuals will be recruited from Baker Heart and Diabetes Institute in Melbourne . Prof. David Dunstan from Baker Institute is an investigator involved in this research.