This Anti Corrosion Free Liquid Level Sensor Circuit show how to make sensor for checking water level in tank or container.
It send small electric signal and uses some metal pins to know if water touches them or not.
No strong chemical is used in this circuit so metal do not get rust or damage.
Circuit Working:
Parts List:
| Component | Quantity |
|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | |
| 470k | 2 |
| 10M | 2 |
| Capacitors | |
| Ceramic 2.2nF | 4 |
| Semiconductors | |
| IC 4093 | 1 |
| Transistors BC557 | 1 |
| Diodes 1N4148 | 3 |
| Relay 12V | 1 |
One IC 4093 can make two CMOS logic gate easy.
IC 4093 have four NAND gates with Schmitt trigger so we can make two parts one for checking liquid level and other one for control.
Because Schmitt trigger gates work better with hysteresis this will help system to be more stable and accurate.
In this project we have used two NAND gates like NOT gate by shorting their input pins and these gates work like inverter with Schmitt trigger.
First gate N1 make oscillator and it send signal to probes.
This signal help stop rusting of probes even if they stay in water long time.
When water touch the probes second gate N2 work like buffer and it allows current to go through the probes.
When small pulse current come N2 input become high logic.
This high logic turn ON PNP transistor and then N2 output become low logic.
This low logic stop water pump using relay and this relay switches OFF when water level is enough.
If using for water or other liquid just connect pump and relay correct way.
If anyone is confuse or need help please write in the comment below.
I will try to answer fast as this sensor is simple and stop rust and is good for water level controller.
Formulas:
We can use NAND gate oscillator circuit also as liquid level sensor.
It help stop corrosion and can use for other things too.
The frequency (f) of this NAND oscillator circuit can be guess using this formula:
f = 1 / 2.2 × R × C
here:
- R is resistor value in ohms
- C is capacitor value in farads
This formula give idea how fast circuit make pulses and is based on resistor and capacitor we are using.
How to Build:
To build a Anti Corrosion Free Liquid Level Sensor Circuit following steps can be followed for the connection:
Power Connection:
- Connect power wires correct way on breadboard with positive to positive and negative to negative.
IC 4093 Setup:
- Put IC 4093 on breadboard.
- Pin 7 go to negative GND to pin 14 which connects to positive (+V) supply.
Oscillator Part N1:
- Connect pin 2 N1A output back to pin 1 of N1A input.
- Put resistor between pin 2 and pin 6.
- Put capacitor from pin 2 to negative rail.
- Connect one probe to pin 1 and also to negative rail and this probe check water level.
Buffer Stage N2:
- Connect pin 12 N2A input to pin 11 of N2A output.
- Second probe connects to pin 12.
- Connect pin 8 (N2B input) to pin 9 (N2B output).
- Put diode between pin 9 and pin 6.
- Use resistor from pin 9 to base of PNP transistor.
- Collector of PNP transistor goes to positive.
- Emitter of transistor goes to one side of relay coil.
- Other side of relay coil goes to negative.
Relay Connection:
- Common (middle pin) of relay connect to pump motor.
- NO (Normally Open) pin connect to power.
- NC (Normally Closed) pin also connect to motor for switching.
- Power ON the circuit and see how it work.
- If needed change resistor or capacitor in oscillator to get better water sensing.
Conclusion:
This Anti Corrosion Free Liquid Level Sensor Circuit is just basic example.
We may need to change parts or design based on our liquid type and what we need.
Always be careful while working with circuits and its components.
References:
Preventing corrosion to sensor by eliminating all voltage on pin?