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Home » Automatic Soap Dispenser Circuit

Automatic Soap Dispenser Circuit

Last updated on 11 July 2025 by Admin-Lavi Leave a Comment

Automatic Soap Dispenser Circuit is like robot for soap.

Inside it have a special plan like electric circuit with small parts.

It has got sensor like small eyes, brain chip like microcontroller, and pump like tiny muscle.

When sensor sees our hand its brain tell pump Give soap! and it gives the right amount.

Circuit Working:

Automatic Soap Dispenser Circuit Diagram

Parts List:

CategoryItemQuantity
Resistors330Ω 1/4 watt3
33k 1/4 watt2
1k 1/4 watt2
Preset 10k1
SemiconductorsIC LM3581
Transistor TIP311
Diodes 1N40072
Sensor IR Diode receiver1
LEDs IR LED transmitter1
LED 5mm 20mA Red1
LED 5mm 20mA Green1
Solenoid 5V1
ON/OFF Switch1
Battery 6V1

Automatic soap dispensers for liquid soap is easy to buy now and they work without touch so less germs spread.

But did anyone ever think to make one for itself?

They can save money and also build it to learn something useful.

Here is one idea for no touch soap machine that gives soap clean and easy.

This DIY project uses IR sensor and small solenoid which runs with 6V DC power.

When sensor sees the hand close it tell solenoid driver to turn ON the solenoid and then soap come out.

Solenoid is good for push and pull like for lever.

If we fix small rubber pipe to solenoid it work like simple valve that stay closed until needed.

Sometimes we need to change solenoid arm with PVC parts to fit rubber pipe but it not too hard.

Building this not very difficult but we must take care with how things are put together.

Put all electric parts inside good ABS plastic box like one module.

When we build it place IR LED LED1 and receiver PD1 in front face down with 10mm gap between.

Tie all wires neat with cable tie.

Only one thing to adjust is preset resistor and no other changes needed.

At start to set preset to middle like 5k + 5k.

Later we can change it a little to make sensor more or less sensitive.

How to Build:

To build a Automatic Soap Dispenser Circuit we need to follow the below mentioned steps:

Prepare Parts:

  • Put the IR sender LED1 and receiver PD1 in front of unit and face down keep 10mm space between them.
  • Fix solenoid with rubber pipe and be sure solenoid can press the pipe properly.

Make the Circuit:

  • Place all parts on circuit board like in circuit diagram.
  • Connect IR sensor, solenoid and power to right pins on board.
  • Solder all parts and keep them strong in place.

Put Circuit in Box:

  • Keep circuit board inside ABS case and bake sure it is fitted well.
  • Use screw or glue to hold it tight.

Connect Everything:

  • Join IR sensor, solenoid and power wires to board.
  • Use cable ties to keep wires neat and not messy.

Set Potentiometer (P1):

  • Turn preset to middle with 5k + 5k.
  • Try moving hand to test sensor if needed and adjust preset to make sensor more or less sensitive.

Final Steps:

  • Close ABS case and use screws to lock it.
  • Check all parts, nothing should be loose.

Testing:

  • Switch ON soap machine and try with hand.
  • If it does not work good then turn preset to adjust the sensor.

Care Tips:

  • Time to time check wires and parts and check all is okay.
  • Change soap and rubber pipe when needed.

Note:

  • This is just a simple guide maybe we need to change some design depend on what parts we have.
  • Be safe when working with electric stuff.

Conclusion:

Automatic Soap Dispenser Circuit is main part for no-touch and clean soap system.

It uses sensor to control circuit and dispenser part to give soap when hand or something comes close.

This circuit help to give soap by itself with no need to touch and is very good for hygiene.

To make this we need to know electronics and how to put parts together and test them.

If we learn well and use right parts we can build our own soap dispenser for easy and clean use at home, office or other places.

References:

Automatic soap dispenser

Datasheet IC LM358

Filed Under: Sensors and Detectors

About Admin-Lavi

Lavi is a B.Tech electronics engineer with a passion for designing new electronic circuits. Do you have questions regarding the circuit diagrams presented on this blog? Feel free to comment and solve your queries with quick replies

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