idea to product proto-type--Daily water intake monitor device

It is reported that there are more than  1 billion CKD ( chronic kidney disease) patients around the world. These patients are required to monitor their  daily intake of water as well as the output of urine. At present the nurses ask them to specify the quantity of water drunk by them  and record it manually in a chart. The patients  do not know the exact quantity of water they drink, cannot remember how many tumblers they had drunk and so they mention an approximate amount that is recorded as their daily intake /output of urine. So the need for an accurate monitoring device that monitors the water intake on a daily basis has been felt by the urology medical fraternity for long.
My idea is to develop such a device that  measures the daily intake of water / output of urine, of the patients concerned,
record the cumulative total for the week and show the average daily intake for the nurses to monitor.         
The device I have in mind is a 250 ml.water tumbler that has a built in quantity electronic sensor at its square base /bottom. The quantity of water poured into the tumbler is measured by the sensor on  cumulative  basis,say everyday, from 6:00 a.m. to next morning 6:00 a.m. or as per time set. The daily intake of water will be recorded from Monday to ensuing  Sunday and the weekly total will be displayed in the monitor. The monitor can be reset after taking the readings.       
The same type of monitoring device for measuring the urine output can be designed in a 500 ml urine collection can for males and females with separate  functional design.     
The device will be powered by suitable energy source like button cell. Settings will consist of daily setting, weekly total and reset. A electronic digital monitor  screen located on the side of the square bottom of the cup base will show the readings.