Aurangabad is in a drought-prone region of Maharashtra. We always have a shortage of water and need to optimize its usage.
In this regard, I made a water level indicator that shows how much water there is in the storage tank, so we can plan the day’s water usage in advance. The water level indicator has an LED display to show the level of water in the two water storage tanks in my house.
It is an extremely convenient little device that has made it much easier for me to check how much water there is. It helps save a lot of effort as, earlier I would have to climb onto the roof and peek into the tank to see how much water there was, and now I can see it on a neat little display in the kitchen.
How it works
There are 7 electrodes in each tank. One is at a high potential, while the rest are the test electrodes. The positively charged electrode is at the floor of the tank, while the test electrodes are immersed up to varying depths. When there is no water in the tank, all the test electrodes are neutral, i.e. in the LOW state. When the water level reaches the depth of the first electrode, the water conducts electricity and pulls the 1st test electrode to the HIGH state, because of the charged electrode at the bottom of the tank. The logic state (or voltage) of test electrode is monitored by an IC (HCF4050BE) which switches on an LED when the voltage exceeds a certain value (using comparators). So the 1st LED lights up when the water level reaches the first test electrode. Similarly, when the water level reaches the second test electrode, it goes to the HIGH state and the 2nd LED lights up and so on. There are six LEDs per tank to display the amount of water, as the IC HCF4050BE has exactly 6 comparators. I have colour coded the LEDs: 1st is red, 2nd and 3rd are yellow-orange, 4th, 5th and 6th are green.
Of the two columns of LEDs, to remember which column is for which tank, I wired the electrodes such that the level for the overhead tank starts from the top (green LED) and the level for the ground-level tank starts from the bottom (red LED).
Water level increasing: (simultaneously being pumped to the overhead tank)
Water level decreasing: (Notice the left LED column)
This device helps me prevent wastage of water. I can easily monitor the level of water, and when the tank is about to fill up, I can switch off the pump without any spillage from the overhead tank. Also I can adjust the water usage of my family when the Municipal water supply is irregular.