In recent years, the number of deaths from opioid overdoses has greatly increased. The Harvey Mudd Exela Health team has built a mobile health monitoring system designed to collect data on patients taking opioids. This system integrates sensors to measure electrocardiogram (ECG), respiration, and motion data. This prototype will be used to help determine how these vital signs are affected by opioid use. Possible future work will implement an overdose detection algorithm to help prevent unnecessary deaths.