BioMod is an integrated interface for users of mobile and wearable devices, monitoring various physiological signals such as the electrocardiogram, with the intention of providing useful and comfortable feedback about medically important information. The first version of this system includes new software for monitoring stress and its impact on heart functioning, and the ability to wirelessly communicate this information over a Motorola cell phone. One application under development is the monitoring of stress in patients who desire to stop smoking: the system will alert an "on-call" trained behavior-change assistant when the smoker is exhibiting physiological patterns indicative of stress or likely relapse, offering an opportunity for encouraging intervention at a point of weakness. Challenges in this project include the development of an interface that is easy and efficient to use on the go, is sensitive to user feelings about the nature of the information being communicated, and accurately recognizes the patterns of physiological signals related to the conditions of interest.