Three-Drink Drink Fountain
Kai Vogeler
ME 2900, Dr. Sandra Metzler, Noah Einstein (GTA)
Department of Mechanical Engineering, The Ohio State University
The Design Process
Purpose
The purpose of my design is to dispense a single liquid, or three different
liquids in pre-determined. The design will dispense the liquid based upon
user-input through five LED buttons and in response to an LCD screen.
Device Background
Motivation
The motivation behind this project is to reduce the use of single-use
plastic bottles among roommates and encourage them to dispense their
drinks from a re-usable plastic water tote.
Current products on the market:
Drink fountains cost anywhere form a few-hundred dollars to a few
thousand depending on carbonation and number of drinks that may be
dispensed at once.
The design process began with an analysis of issues present in the
household. Water bottle use was identified as a major issue because of
its damage to roommate relationships and the environment.
Once the problem was identified, roommates were interviewed to discover
what their requirements were for using a system to fill their water bottles.
With requirements in place, the framework for operation was drafted.
Multiple water flow systems were considered including using gravity for
water flow and solenoid valves or solenoid valves and pumps. Eventually,
it was decided to use peristaltic pumps and separate fluid lines to reduce
complexity and contamination. The major constraint leading to this choice
was financial limitations. Low pressure solenoid valves cost four times
more than peristaltic pumps without significant improvements in flow.
Functional Requirements
1. User input controls the selection and dispensing of
fluids.
2. Must be able to fill a 300 ml cup in one minute
3. Must be able to dispense up to three separate liquids
simultaneously
4. Must provide visual indication of selected drinks.
5. Must allow user confirmation of selected drinks prior
to dispensing.
6. Must allow user to stop flow of liquid within 0.25
seconds.
Non-functional Requirements
1. Must cost less than $75.
2. Must fit in a 1ft x 1.5ft x 1ft
box.
3. Must have architecture for
future expansion.
Figure 2: Functional and non-functional requirements
Major Design Components
Figure 1: photograph of plastic waste in pacific ocean.
Problems with current products:
• The problem with single-use plastics is the immense damage they
cause to the ecosystem. 8 million tons of plastic make their way to the
ocean each year.
• In addition to the cost of the environment, the plastic bottles are left by
roommates all over the apartment. By switching to re-usable bottles, they
will cease to litter the household.
2x16 LCD display
5 x LED buttons
2 x Serial motor controller
Peristaltic pumps
Serves to inform the user of the current state of the
program and indicate the function of each button.
Allow user input into the program and provide indication
of drink selection.
Figure 4: drink fountain components
Clockwise from top left: LCD screen and overall circuit, Peristaltic pump, LED button, Serial motor
controller
Testing and Analysis
Testing of the components will be ongoing. Testing will include rigorous
software testing to ensure that the buttons do not engage without the intention
of the user and that the user has full control over the dispensing process.
Additionally. The hardware will undergo testing to ensure that no leaks will
jeopardize the electronic components or cause damage to the surroundings.
The device will only be accepted after the software is ensured to be error-free
and the structure provides a safe and efficient pour of water.
Allow simple control of the three DC motors driving
peristaltic pumps.
Provide liquid flow when DC motor is powered.
Figure 3: Major components used in the design
Photos of each component can be seen in Figures 4.
References and Acknowledgements
Thank you to the Arduino community for the open-source resources and help that brought this device to
life. Thank you also to Noah Einstein for his assistance in debugging the button process.