This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (www.makecourse.com)
My name is Alexander Murphy, and I am in the MAKE course at the University of South Florida. For Fall 2014, I chose to make a liquor dispenser utilizing 3-D printed parts and an arduino controller. In this instructable, I will be showing how to reproduce my project, highlighting the components I used, and will go through the arduino sketch I programmed to make everything work.
Step 1: Components
These are the components I used in this project. There is a small pump from lightobject.com a stepper motor, ultrasonic sensor, and arduino uno. These last three components all came with the MAKE course kit, but are readily available for low prices on the internet. Not shown, you will also need leaders, a bread board, and motor attachment for the stepper, a transistor, and a very small resistor. Also form lightobject.com, I used the orange sized tubing to fit on the pump. You only need the smaller side, because I designed the reservoir to snugly fit the large end. Other than that, you might want to buy three or four shot glasses. :)
Step 2: 3-D Printed Parts
All of my 3-D printed parts were designed using Solidworks, and printed using the Makerbot Machines and software. Shown, my turn table has three depression in a disk. Underneath there is a small hole which should fit on the top of your stepper motor. The designing of this is pretty straight forward. The tall tower section simply needs two compartments, and space underneath to put the pump and lead the wires into the box portion. The spout is just a rectangle with holes at either end. The box is just a box with two holes, one for the arduino power and one for the pump wires. The spout, box, turntable, and reservoir were all printed separately because they were too large to be printed in a single print. I used Devcon epoxy to glue it all together. This glue is amazing and is more sturdy than the plastic itself once dried. I sprayed the inside of the reservoir with a food grade pottery sealant because pla leaks to printing inconsistencies.
Step 3: Control Diagram
This is a control diagram of all my components working together. You will need an external power supply to power the stepper and the pump. It isn't necessary to power the stepper in this manner, but it is much safer for the arduino. The diagram is pretty self explanatory. The stepper rotates a third of a full rotation, and then the pump activates. This is where the transistor comes into play.
Step 4: Wiring and the Stepper
Here I've shown very briefly how to wire the stepper or pump. Note the first picture leaves out the motor driver, but I included that to show you how to use the transistor to run an external batter. The stepper motor takes up four of the pins on your arduino, the pump takes up one, and the ultrasonic sensor takes up two.The
Step 5: The Code
Here is the code for the Arduino. This Code is very straight forward. The only interesting thing is the use of an integer counter. I included this so that the system wouldn't activate every time the sensor acted up. This ensures that there is actually a hand there within 8cm for 10 cycles. I have included annotations within the code to explain it.
Step 6: Final Project
Here is the final project. The only issues it has are that is has trouble fully dispensing all of the contents in the reservoir. I usually just dump it out when I'm done using it. Again, as I said before, make sure you don't dispense if there is no glass to catch it, it will spill, hence why I made the sensor so sensitive. If you are attempting to make a replica of my project, I wish you luck. :)