I thought about this along the way. It would be really cool to have some alert that says, "Baby is probably ready for a nap" or "Baby probably needs a diaper change", but the ML side of that is far outside my domain. Did you get far enough to judge whether or not such a thing would be very feasible, given how babies can develop so drastically differently?
I didn't get far enough, unfortunately. This was a number of years ago, and not the panacea for ML/AI that we have now. The variance in data is certainly a concern, but the free/inexpensive nature of the app itself was intended to gather as much as possible (anonymity being absolutely key, given the subject) and start looking at data points vs. positive ratings to find the correlation.
At the very least, that sort of data would be incredibly value for academia/research etc.
