An incredible amount of waste is created in the dry food section at grocery stores. This is due to the manual dispensing machines that have an unpredictable flow rate that causes food to spill when a customer is using it or causes the customer to obtain too much food. Furthermore, a lot of times when a customer receives too much food from the dispensing machine, they tend to leave the overfilled bag somewhere in the store and get a new bag with a lesser amount. The bag that is left on the shelf will have to be discarded to avoid contamination. The Wolf Food Solution’s idea for this problem is to create an automatic food dispenser that the customer can select a specific amount of food on an LCD touch screen and then the machine will dispense that amount into the customer’s bag or container.
Wolf Food Solution’s basic design requirements are for the machine to be as simple as possible for the customer to use. This comes down to making the user interface for the LCD touchscreen easy to use. This will help eliminate the problem of people obtaining too much food and leaving the waste in the store. Also, the automatic food dispenser shall dispense the food in a very controller manner to eliminate the spilling problem that some customers have when filing their bag or container. The machine will dispense by either weight or volume, dependent on the final design decision of the team. The machine will also be designed to fit the pre-existing shelves in every grocery store, so the automatic food dispenser can be swapped out quickly for the old and inferior manual dry food dispenser.
Wolf Food Solutions is making a dry food dispenser that is being designed to be placed in grocery stores. Stores such as Whole Foods and Winco with their bulk dry food sections are some of the main target customers. Wolf Food Solutions has two main competitors, Trade Fixtures and Rosetto Serving Solutions. Between the two companies, they share almost the entire market so it will be difficult to get past the competition. Wolf Food Solutions plans to try test markets in order to get the product into stores and see it become a success. The team plans to distribute the dispensers regionally to start out small and work their way to having dispensers around the area.
Proof of Concept
This food dispenser will be a direct replacement for the ones used in grocery stores. It will use a rotating cylinder to pick up the food and drop it out of the bottom. The clear box on top is made out of acrylic and will keep the food safe and dry until it is dispensed. The lower section is made out of 3D printed PLA. It is strong and will withstand the constant use in the stores. Simply put, the automatic dry food dispenser reduces the mass flow rate or dry food compared to manual ones found in stores. Some hand calculations on the mass flow rate demonstrated this when our team ended up with a calculated mass flow rate of 3.2 kg/s compared to 10 kg/s for the manual dry dispensers in stores. So the design with a rotating trough that controls the flow of food has proven to be better than what is found in stores.
The product design specification has been simplified since the first design. The rod is 6” long and 3” in diameter and can carry a half cup of food in each trough. The rod will be 3D printed and will be designed to fit snug over the rotating rod on the 6V DC step motor. The ramps at the bottom and top are all angled at 30 degrees since this was tested angle to allow the appropriate mass flow rate. The body is made of a smooth wood and so are the ramps. The wood must be smooth so the coefficient of friction is low and the food can slide over it easily. ¾” screws are going to be used to hold the wooden structure and ramps together. For user input, there will only be a single button switch that when pressed, the rod will rotate counter-clockwise a half rotation and release a half cup of food. There will be access on the west side of the product to remove the rod for cleaning. The machine will be powered by a 12V tenergy battery and the controller will be a raspberry pi zero. This will be coded with Python. The form factor will be compatible with what is in the stores now so the store does not have to add new shelving to hold the product.
The Automatic Dry Food Dispenser will be incredibly easy for the consumer to use since it only takes a press of the button. With that single press of a button the user will know exactly how much food they are getting making shopping easier and eliminate the tremendous waste. The store that uses this product will see a greater profit by the eliminated waste, and this product is eco-friendly since there is no more wasted food. This design is simple so the access into the electronics from the side will make cleaning very easy and allow a very extended shelf life.
The majority of the parts will be bought as is such as the motor and controller. The rotating rod will be 3D printed of polylactic acid (PLA). The body of the container will be made of acrylic and the lid will be made of plexiglass. Once the body is assembled, the rotating rod will be placed inside of the body and connected to the motor and controller. Next, the lid will be secured to the top of the body with screws. The final step of the assembly is to code the controller with Python and calibrate it to rotate the rod and dispense ½ cup of food per rotation.
Testing and Results
The test plan for the dry food dispenser involved a series of rigorous activities that checked the structural, mechanical and electrical capabilities of the dispenser. To check the structural integrity of the material used in fabricating the dispenser, a simple force test was done on the material. The walls of the dispenser’s container are made of acrylic and the tensile strength of acrylic is approximately 69 MPA. So, the container was hit several times with an object that recorded the impact force. After every impact, the surface of the acrylic container was examined for cracks, dents and fractures. It was found that forces below the tensile strength did not produce any faults.
|Trial||Force Recorded (N)||Fractures or Cracks (Y or N)||Dents (Y or N)|
Figure 1: Acrylic Force test results.
The mechanical capability was evaluated by ensuring all mechanical components worked and the amount of food dispensed by the dry food dispenser at a time was only 1/2 cup.
The electrical testing was more intense as all electrical components had to be checked . The team had troubles at first getting the wiring and programming to work with the Arduino, battery, button, stepper motor, and the electronic driver. There were many times that the electronics did not work correctly due to wrong connections that drained the battery. The program also needed to be re-written multiple times to make it simple and efficient. Once the electronics started working correctly, the dispenser worked perfectly fine.
Overall, the testing of the dry food dispenser was a significant success. The dispenser was tested an average of five times for consistency and accuracy. The dispenser performed all the desired functions and tasks it was designed to do. The enormous waste generated by dispenser was completely eliminated in this dispenser. The dispenser ramps and troughs drastically reduces the flow rate of food avoiding spillage and it also allows the user to know exactly how much food they are obtaining. This way customers do not need to constantly weigh how much food they are getting, making it easier on them.
The dry food dispenser solves the problem of waste generated at dispensing stations. There are too many cases of wasted food being dropped out of gravity fed dry food dispensers. People also leave food around the store because they obtained too much and this also creates waste. Furthermore, users seemed very pleased with the automatic dry food dispenser because of its goal to eliminate waste. It is also very simple to use and propels technology of shopping into a more automated and simple process. The product design matches the purpose that the team initially had planned by controlling the rate at which the foods dispenses and allowing the customer to know exactly how much product they are getting.
Video shows the team measuring/checking all the mechanical component of the dry food dispenser works.
Meet the Team
Samantha Koepp: Samantha Koepp is a senior at the University of Nevada, Reno pursuing a Bachelor of Science in Mechanical Engineering with a Minor in Mathematics. She is originally from Livermore, California, located in the east of the Bay Area. Through her academic career, Samantha has gained knowledge about many engineering topics such as thermodynamics, heat transfer, and mechanics of materials. She will be the first member of her immediate family to graduate from a four-year university. Samantha has worked at a Reno based mechanical engineering firm, Ainsworth Associates Mechanical Engineers, for the last two and a half years. At work, she is able to apply her knowledge of heat transfer and fluids to design and select mechanical systems for HVAC and Plumbing. After she graduates, she and plans to continue working Ainsworth and pursue her dream of becoming an entrepreneur by starting her own company.
Peter C. Olisa is a mechanical engineering senior at the University of Nevada, Reno. Originally from Nigeria, Peter believes in creating a future is full of possibilities. Peter has embarked on numerous engineering projects like building an EMG robot, and designing an intrinsic system for auto theft prevention. Peter has numerous engineering skills: He is proficient in C++, Solidworks, Catia and Matlab. Peter also works with SA Automotive, a subsidiary of Tesla, where he is a part of the engineering team making headliners for the new Tesla model S. Peter plans on going to graduate school after getting his BSc. in Mechanical Engineering and he hopes to obtain an MBA in Business & a doctoral degree in Advanced Mechanics.
Originally from Orangevale, California, David Sharpe is a senior mechanical engineering student at the University of Nevada, Reno. He is experienced in Solidworks, Inventor, Solid Edge, AutoCad, and Python. David has had three engineering internships over his time studying mechanical engineering. Two were at T&D Machine products designing custom engine parts, and the third is for Lincoln Electric Cutting Systems in their R&D department developing and improving their plasma cutting machines. After graduating David has plans to start an engineering company with a few other UNR students.
Trent grew up in San Luis Obispo, California who is currently getting his Mechanical Engineering bachelor’s degree at the University of Nevada, Reno. While getting his degree he obtained an internship where he designs high bay LED lighting systems. He has used many of the skills he learned in school at his internship by designing custom brackets to mount the lighting systems. Through school and working he has learned to take one step at a time when there seems to be too much work ahead of him. Having a calm mind does wonders for his ability to take on large tasks. Outside of school, Trent has become proficient in the coding languages C++ and Python. After Trent gets his degree he wants to get right into an engineering position, but, this is short term. He is currently working on a business plan where he hopes to eventually become a full-time
Tyler Schmaling was born and raised in Las Vegas, Nevada where he attended a technical high school and first learned of his interest in the engineering field. Tyler is currently a senior in the mechanical engineering program at the University of Nevada, Reno. Throughout his college career, Tyler has taken courses in many subjects and picked up skills in various mechanical disciplines. Both inside and outside of school, Tyler has become proficient in programs such as MATLAB and Solidworks. Upon graduation, Tyler would like to work in a manufacturing industry in an area that he is passionate about.