This is a home made machine that sprays alcohol when you come near. The ultrasonic sensor detects your hand and makes the servo turn and press the leverage to spray alcohol.

The link to the code is :

https://create.arduino.cc/editor/terry_outsider/df...

The link to the finished video is:

Step 1: Materials

Hot glue gun

Hot glue sticks

Spray bottle with spray heads

Ultra sonic sensor

servo motor

arduino Leonardo

bread board wires

bread board

Gigo blocks or other kind of lego blocks

Step 2: Steps:

1. You can make a structure that stables the spray bottle. Any kind of structure that stables the bottle works. Be sure to let the cam able to turn and press the leverage of the spray.

2. Find the place where you put the cam on. Predict where you should put the axis of the cam. The cam should be able to press the leverage and spray the liquid inside out.

3. Stick your servo motor on a structure and the rod that turns the cam. (Adjust your angle of cam first,) You can use hot glue or lego blocks to stable it.

4. Put the ultra sonic sensor on a plate that senses where the hand comes, make sure nothing blocks the sensor.

5. Aline the wires of the servo and ultrasonic sensor and organize them. make sure the lines and circuits doesn't fall or detach during the test.

6. You can add cover or decoration to make it more beautiful

Step 3: Source

https://www.instructables.com/id/DIY-Easy-Non-Cont...

I got the idea from this site.

I changed the way the servo is turned. Also, I used a cam instead of fishing lines. My stabling structure is made of plastic Lego blocks not like the material in the source. I also exclude the button because I think it is unnecessary.