Biomonitoring devices, methods, and systems for use in a bathroom setting

A biomonitoring device that measures a parameter of a material expelled into a bowl of a toilet by a user, the device comprising

• (i) an electromagnetic radiation source above the material, wherein the electromagnetic radiation source emits electromagnetic radiation into the bowl of the toilet,
• (ii) a sensor comprising a lens above the material that detects electromagnetic radiation or an analyte chemical in the bowl of the toilet, and
• (iii) a transmittal unit that transmits data to a computing unit,
• wherein the device undergoes a training period where data is analyzed when no excreta is in the bowl, wherein the training period comprises taking baseline sample images when no excreta is in the bowl and obtaining a baseline model of the empty toilet bowl from the baseline images.