Water conservation is the biggest concern these days. Smaller human error can lead to gallons of waste of water due to improper system management of water. Using this project, we are going to implement an automatic timer-based water pump triggering circuit which is designed in such a way that, once it turns-On it will auto OFF the pump after a particular time. The idea is implemented using 555 popular timer IC, which works in Astable, Monostable, and Bistable modes. All three modes have different operating circuits with 555 IC and different outputs.
We are operating the IC in the monostable mode where a small triggering triggers the output High which is the unstable state because the Capacitor & resistor values will set the timing of HIGH State (See later).
It is a beneficial real-life project that can be implemented in various sectors like water plants, water tanks, and households where no need to Turn it off once you turn it ON. The implementation is quite easy and can be easily done at cheap prices, it is also portable and durable (if fitted inside a case).
Components required:
- NE555 IC with 8-pin header leg
- L293D IC
- 3V to 12V Mini DC Submersible Pump
- LM7805 voltage regulator IC
- Breadboard
- 12v Battery & its connector
- Push button
- 100k, 10k resistor
- 100µF and 1000uF Capacitor
- 5mm LED Bulb
- Jumper Wires & Single strand Wire
Automatic Overhead Water Control Timer Circuit
- The Input supply is 12v but then we integrate 7805 to convert 5v to power both IC as well as to run the pump motor. The first pin of 7805 takes 12v input whereas the other gives an output of 5v where the input-output Ground is common.
- The output 5v is passed through a 1000uf capacitor to make it perfect filtered DC and input to 555 and L293D IC.
- 555 timer IC: The IC has a total of 8 pins named GND, TRIG, OUT, RESET, COUNT, THRES, DISCH and VCC. All connections of 555 can be referred to from the above circuit diagram. The 100uf capacitor and 100k resistor will set the unstable mode timing output which can also be calculated via the T = 1.1 * R1*C1 formula. The pin1 is Ground pin of the IC, pin8 is the power pin of the IC, the pin3 is the output pin which is connected to a 5mm LED bulb. You can initially put an LED there to check the output logic of the pin3. In our case, the pin3 is HIGH in unstable mode while it’s LOW in stable mode. Hence pressing the button triggers the circuit and the LED will start to glow and after a couple of seconds, it will LOW.
- L293D IC: This 16-pin IC functions as a half H-bridge motor driver, with the capacity to simultaneously drive two DC motors or stepper motors. It enables independent control of each motor’s direction and Speed control. We are using only one side of the IC to control our Single Motor pump.
- The IC has a total of 16 Pins which are:
- Pin 1 (1A): Input for Motor 1.
- Pin 2 (1Y): Output for Motor 1.
- Pin 3 (2A): Input for Motor 2.
- Pin 4 (2Y): Output for Motor 2.
- Pin 5 (1Y): Output for Motor 1 (complementary).
- Pin 6 (1A): Input for Motor 1 (complementary).
- Pin 7 (1B): Input for Motor 1 (enable).
- Pin 8 (GND): Ground.
- Pin 9 (Vcc2): Power supply for IC.
- Pin 10 (2B): Input for Motor 2 (enable).
- Pin 11 (1B): Input for Motor 1 (complementary).
- Pin 12 (1Y): Output for Motor 1 (enable).
- Pin 13 (GND): Ground.
- Pin 14 (2Y): Output for Motor 2 (enable).
- Pin 15 (2A): Input for Motor 2 (complementary).
- Pin 16 (Vcc1): Power supply for IC.
IC can drive a motor of output voltage 4.5 to 36v at VCC2 Pin with 600mA of continuous current as well as 1.2A of Peak Current.
Pin VCC2 is separated from pin VCC1, Vcc1 is the power supply to the internal circuitry of the IC ranging from (4.5v to 7v) whereas Vcc2 is the separate supply for motor output ranging from (4.5v to 36v).
- If Pin 2 is HIGH and Pin 7 is LOW, it creates a Clockwise Direction rotation
- If Pin 2 is LOW and Pin 7 is HIGH, it creates a Counterclockwise Direction rotation.
- If Pin 2 is LOW and Pin 7 is LOW, it is Idle or No rotation condition.
- If Pin 2 is HIGH and Pin 7 is HIGH, it is Idle or has No rotation condition.
Process flow of Automatic overhead water Control
The 555timer IC is Set in unstable mode for a particular time as per our circuit design. Hence the HIGH output of the timer circuit will work as a logic input for the L293d IC for rotational direction and can be inputted to the IN2 pin of the L293d IC whereas the IN1 pin is grounded. Such a combination of IN1 and IN2 creates the LOW-HIGH logic respectively.
Thus, the 555 timers will serve as the core timing component, controlling the activation and deactivation of the motor driver IC responsible for starting and stopping the water pump through which the water flow can be controlled.
When LOW-HIGH Logic inputs to the L293d IC at pins 2 & 7 the pump starts running while when providing the same logic to both pins which is either HIGH or LOW, then the motor will stop.
Demonstration of Automatic Overhead Water Control System
- Fine-tune the timing as per your requirements by changing the values of the capacitor and resistor.
- Our values of 100uf and 100k can drive the pump for around 10 seconds with a single pushing button.
- Press the Push button to run the pump for the desired particular interval of time.
