Results

Movie of the final product!!
      After two weeks of building and trouble shooting, we achieved all of the goals set forth in our project proposal. We created a robust, reliable machine for making any type of powdered drink. It was able to consistently measure out powder and liquid and mix them together for a specified amount of time. It also contained safety features so that the drink-making process could not be started if the door was open or if no cup was in the machine. However, not everything turned out exactly as we had planned:
  • Even though the valve we used had a large opening, the adapters we used to connect the valve to the plastic tubing were very small. This caused the liquid to flow very slowly; it took approximately forty seconds to fill half of the cup. On the other hand, the connections were water tight, so the liquid did not leak out and make a mess.

  • The connection to the liquid reservoir was also water tight, but that took a lot of trial and error. The first two types of glues we used did not create a good seal, and the third glue contained ingredients that would have been very harmful if they had been ingested. This is why no one could drink the lemonade from the machine on the day we presented. However, after replacing all of the tubing and the storage container, we found a silicone sealant that worked well.

  • Our mechanism for powder dispensing worked well, but after numerous runs (on the day of the demonstrations in Tech lobby) powder started to work its way underneath the block and out onto the top shelf. There were also a few occasions where some of the powder missed the cup and dusted the middle shelf. The second problem could be solved by using a larger cup or by using a smaller hole to dispense the powder. It would also help if the top of the cup were closer to the top shelf. The first problem is a bit more complicated, but could probably be helped by redesigning the dispensing block in the manner shown below.

(click for larger image)

  • When we ran the machine enough to see that powder was indeed leaking out, we also noticed another problem: our machine was very difficult to clean! All of the important components are on the top shelf, which is only accessible by removing the funnel for the powder. Originally we had planned to secure the funnel in place, but we changed our minds when we realized that it was our only avenue for cleaning powder spills and making adjustments to our motor, valve, and mixer. This problem could be easily solved by putting a taller front door on the machine. If the top of the door extended above the top shelf, we would have had unlimited access to all parts of our project.

  • In our original proposal, we stated that the interface of the machine would have three LED lights to let the user know what stage the machine was in. Instead of doing this, we opted to make the walls of our machine out of plexiglass so that the users could see for the process for themselves. This solution served the same purpose, but was much simpler because it did not require any extra circuitry or programming.