A ULN2003 Integrated Circuit (IC) is necessary to complete this project. This is a tiny set of premade electronic circuits that are mounted on a flat piece of silicon. [2] X Research source You will also need 3 LEDs, which are used for indicating when the water level is low, moderate, and high. 1 buzzer is necessary to signal when the water level is high. 5 sensing wires are needed for measuring the water level. The length doesn’t matter, as you will be cutting them to size later on. You can also solder sensing wires together if one is too short. A 9-volt battery and a battery connector are required to provide energy to the water level indicator.
Pliers are necessary for preparing the IC to add the LEDs. A soldering iron and solder are key for most electronics projects. This is how you will connect the circuit together. You will also need wire cutters to cut the sensing wires to size.
The shorter sensing wires measure higher water levels, while 1 of the longest wires measures the lowest water level. The other longest wire is for the buzzer, which signals when the water is at the highest level. [6] X Research source
The negative point on each LED is the short lead, while the positive point is the long lead. [8] X Research source Rest the IC flat in front of you to understand how the pins are numbered. There are 8 pins on each side and a notch at one end of the IC. With the notch toward the top, pin #1 is next to the notch on the left side and pin #8 is at the bottom left side. Pins #9 to #16 are counted up the opposite direction with pin #16 being next to the notch on the right side.
Because pin #12 is already connected to an LED, you need to solder the negative point of the buzzer to the negative wire of the LED that is connected to pin #12. Even though the buzzer isn’t attached directly onto pin #12, it still works because the wires are connected in a circuit. The negative point on the buzzer has a shorter lead than the positive point. This is the same as the LEDs. [11] X Research source
This means that the LED that’s connected to pin #16 lights up when the water level is low, the LED at pin #14 lights up when the water level is moderate, and the LED at pin #12 lights up when the water level is high. The buzzer will also indicate when the water level is high.
Now that the battery is connected, your water level indicator is able to work!
It’s necessary for the buzzer to let you know when the water reaches the highest point, as this prevents it from overflowing and stops the water being wasted. [17] X Research source
