Final Verdict

Overall, the prototype and the competition went well. Aside from a very strange abnormality that we encountered as we were setting up for the competition, everything at the event  went much smoother than expected. The abnormality that was just mentioned was a problem with the communication between the distance sensor and the Arduino. The sensor was reading random distances that ranged from 0 to 163 inches, thus triggering the program and the machine at random times. We are not quite sure why it happened, but we especially don't know how we fixed it. All of a sudden it just decided to work perfectly. After that point, everything was smooth sailing.

During the event we had a lot of people who seemed very interested in our project, and a few that spent a lot of time talking to us about how we can take it farther. Although we did not make the finals, we were proud of how we did since we received a shocking number of votes. We had little expectations for the event, but we left feeling very good about ourselves and the final outcome of the project itself.

Below is a video of the finalized project in action

Final Team Blog Post

Final Team Blog Post


This is the part of the code that outputs the trigger pin of the distance sensor and gets the input back from the distance sensor in the echo pin.  The duration between the trigger pin and the echo pin is then changed into inches.  Th value of which is used in the following while statement to trigger the rest of the vending machine.

long duration, inches;
  pinMode(trigPin, OUTPUT);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);

  inches = microsecondsToInches(duration);


This is the Google Drive link to all the solidworks parts as well as the assembly and the final Arduino code used.
https://drive.google.com/open?id=0B0ebIYzkcYyTVXd1WTVmdFNMUWs&authuser=0

This is one of the front faces of the vending machine.  This part was 2D cut from Opaque Acrylic.  The main cut was the door opening, while the smaller cut is the coin slit.  The other 2D laser cut parts were one of the sides and the roof, which were made out of whiteboard.


There were no 3D printed parts used in the final prototype product because we were stretched on time since we were doing the Dean's prototyping competition.  The 3D printer was also down during the time that we needed to get something 3D printed, so we had to improvise.

The bulk of the manufacturing was hand built using leftover wood parts, plywood, and metal brackets.   The hand built parts of the design were joined either with screws or with nails.  The 2D laser cutted parts were joined to the rest of the prototype with Gorilla Glue.