I divided my making process in 3 steps.
FIRST STEP -
At first I made the structure of Smart Dispenser-Bot.
Now I will discuss how the hand wash drops automatically. First I install the Tower pro MG945 servo motor inside of the structure, then I used a string which I attach with the servo motor.
After that I placed the hand wash in the ground of the structure (back side) and put the string on the cap of hand wash bottle (Details given in pictures bellow). Then I attached the servo motor (Tower pro MG945) with a microcontroller (Arduino UNO) and I attached a Ultra sonic sensor (HC-SR04) with the same microcontroller (Arduino UNO) in front of the structure ( Details is given in pictures bellow ).
[Work process - When someone access their hand in the instructed place of the Smart Dispenser-Bot, then the ultra sonic sensor sense that hand and send a signal to the microcontroller
after that the microcontroller send a output signal to the servo motor to rotate 180 degree, for the rotation of servo motor the rope will got a pull and the liquid will come out from hand wash bottle.
SECOND STEP -
There is a servo motor in the structure which is pasted by the glue gun and I fixed a Tactile switch in the slide of servo motor. After that I connect a arduino with that servo motor.
Then I connect a MP3 Player with the tactile switch. When the servo motor rotates 180 degree then the tactile switch will activate MP3 player.
[ NOTE: I already insert a SD-card in the MP3 and a speech is already loaded in the SD-card.]
[ NOTE: Speech loading process - First you have to open google chrome and search 'TEXT TO SPEECH' then you have to go to the text and write a some specific text which you want as the speech,
then click on start and download it in your SD-card and insert in your MP3 player.]
[ NOTE: You can record your voice and use it ]
[If you don't want to use MP3 player then you have to use SD Module.]
THIRD STEP -
My model works in DC current, so I use a AC to DC converter (here I use a charger 5 volt 2 amp). First use a five pin plug and then insert the charger there. Now take two OTG cable and cut red and white wire separately and placed it parallel connection and connect with that charger. Now connect those two OTG
cable with those two arduino.
[ NOTE: You can use your power bank as power supply.]