Let us review the two basic fertility sensing techniques (LH concentration measurement and BBT measurement) before going to the overall system design.
(i) Urine based LH concentration measurement:
Here a test strip is used which has three marked levels:
1. Stop line
2. Test band
3. Reference band
Initially, only the stop line marking is present in the strip.
A small amount of the women’s urine is taken in a cup. The test strip is dipped into the cup in such a way that the urine level does not exceed the stop line marking (refer to Figure 3).
Figure 3: LH testing procedure
This strip is removed after few seconds and kept flat for a few minutes, after which appear the test band and the reference band. The reference band used for comparison, and if the test band is darker than the reference band, this indicates a higher LH hormone concentration. In other words, it indicates that the woman is about to reach her ovulation period. If it is lighter, this means she has not reached the ovulation period yet. (ii) BBT measurement:
Here a good quality temperature sensor is used to measure the woman’s body temperature every morning. As shown in Figure 2, the BBT remains low before the ovulation day. A sudden hike of about 0.2-0.3°C in the basal body temperature measurement indicates that the ovulation day should occur in a day.