Automatic Soap Dispenser Circuit is like robot for soap, inside it have a special plan like electric circuit with small parts; also, it has got sensor like small eyes, brain chip like microcontroller, and pump like tiny muscle.
Hence, when sensor sees our hand its brain tell pump Give soap! and it gives the right amount.
Circuit Working:

Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors | 330Ω 1/4 watt | 3 |
| 33k 1/4 watt | 2 | |
| 1k 1/4 watt | 2 | |
| Preset 10k | 1 | |
| Semiconductors | IC LM358 | 1 |
| Transistor TIP31 | 1 | |
| Diodes 1N4007 | 2 | |
| Sensor IR Diode receiver | 1 | |
| LEDs IR LED transmitter | 1 | |
| LED 5mm 20mA Red | 1 | |
| LED 5mm 20mA Green | 1 | |
| Solenoid 5V | 1 | |
| ON/OFF Switch | 1 | |
| Battery 6V | 1 |
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?
Also, they can save money and 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 and sometimes we need to change solenoid arm with PVC parts to fit rubber pipe but it not too hard.
Hence, building this circuit is not very difficult, but we must take care while assembling it; we should place all electrical components inside a good ABS plastic box as a single module.
When we build it place IR LED LED1 and receiver PD1 in front face down with 10mm gap between and then tie all wires neat with cable tie.
We only need to adjust the preset resistor, no other changes are required.
At start to set preset to middle like 5k + 5k and then 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:
- First, put the IR sender LED1 and receiver PD1 in front of unit and face down keep 10mm space between them.
- Then 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 and then connect IR sensor, solenoid and power to right pins on board.
- Solder all parts and keep them strong in place.
Put Circuit in Box:
- Now place the circuit board inside an ABS case and make sure it fits well and use screws or glue to hold it securely.
Connect Everything:
- Join IR sensor, solenoid and power wires to board and 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 and then check all parts, nothing should be loose.
- Switch ON soap machine and try with hand and 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 and 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 and also be safe when working with electric stuff.
Conclusion:
Automatic Soap Dispenser Circuit is main part for no-touch and clean soap system, as it uses sensor to control circuit and dispenser part to give soap when hand or something comes close.
Furthermore, this circuit help to give soap by itself with no need to touch and is very good for hygiene and to make this we need to know electronics and how to put parts together and test them.
As a result, 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.
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