This Soap Dispenser Will Crush Your Germs

When it comes to cleaning your hands, [Arnov Sharma] is not messing around. He built an automatic soap dispenser using ultrasonic sensors, a stepper motor for activating the pump, and 3D printed components for housing a bottle of soap – a spectacular display of over-engineering. At least he won’t be needing to stand in line at the supermarket for motion detection soap dispensers anytime soon.

Initially, he had the idea to build the dispenser using a common servo motor-based method.  This would involve activating motors to push down on the plunger for the soap bottle to dispense soap. Instead, he for a different approach that ended up being fairly straightforward in theory, although the execution is pretty involved.

Model of the soap dispenser made in Fusion 360

He started off by 3D printing the compartment where the soap bottle would sit and the structural support for the Z-axis rail that would be pushing down on the soap bottle. It’s similar to the type of linear actuator you might find in a 3D printer or PCB mill, where a motor controls a rotating screw that moves the carriage across a belt. (We presume the linear rail came first, and the ultrasonic soap dispenser second.)

In this build, there are two additional rods added to help support the lever pressing down on the soap dispenser.

The setup is controlled by an Arduino, which triggers the movement from the linear actuator if it receives a signal from an ultrasonic sensor. He’s added the model files and Arduino code for other makers curious about building a similar project. Check out his video for the soap dispenser in action – the stepper motor definitely makes for a much more powerful plunge than you might expect.

12 thoughts on “This Soap Dispenser Will Crush Your Germs

  1. How does it implement the face detection? To enable the regular mode of operation where it doesn’t respond to a static or wiggling hand, but waits until the user turns away to see if there’s another soap dispenser, then squirts it on the floor.

    1. If you think that’s a white power symbol, you’re just doing their work for them. Jerks on 4chan made that shit up to make you look foolish and trick people into turning on each other. Don’t be a damn rube.

  2. I bought a US$30 soap dispenser from Amazon that uses an IR sensor, and it kinda sucks as far as getting the hand detection to work. I think this project is great… apparently this is a device that needed a little overengineering!

  3. Around my area they sell the “Sagrotan no-touch” https://www.dm.de/sagrotan-seifenspender-no-touch-geraet-nachfueller-tropical-mit-melonen-duft-p4002448122906.html – for 7€ including a bottle of soap! Once the bottle was empty, I drilled a hole in its top, refilled it with my favourite liquid soap and placed some sticky tape over it. Done.
    Was probably one of the simplest but most useful “hacks” ever.
    BTW: I bought this thing around 2 years ago. It’s super reliable and still runs on its first set of AAA batteries XD.

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