Cardiac rehabilitation programs are traditionally carried out in hospitals and health centers under the direct personal supervision of mentoring clinicians. Patient barriers, such as time constraints and distance from treatment centers, have lead to poor uptake of programs among eligible patients. To overcome these barriers, home-based care models have been proposed as a viable alternative to hospital-based cardiac rehabilitation programs. We have developed a measurement system and software tools on a mobile phone platform enabling patients to participate in a home-based cardiac rehabilitation exercise program. A mobile application, TuneWalk, gives guidance to the patients during home exercises using heart rate and physical activity analysis and also stores long-term information about their progress during the weeks of the rehabilitation program. The measured data are also sent to a server for remote exercise performance analysis and consultation by the patient's personal mentor.