A slideshow of our presentation can be found on Slidshare.
On Monday, December 10 Katie, Liz and I presented our final Physical Computing project in class. We started with a demonstration:
Then we discussed our process, reviewing the work we’d done since the final (presented here in the previous Playtesting & Prototyping post) and then summarizing our most recent work. In the week between our continued playtesting & prototyping presentation and the final presentation, we did a lot, including a redesign. After building the mechanism from chipboard, we thought we were ready to construct the final product from acrylic and put it on the plywood backing. As an extra precaution, Katie created this great and exact diagram specifying the placement of the parts on the backboard:
We knew we would have to adjust the placement of the counterweights, so we first assembled the arms using blue tape since the plasti-weld is quite permanent. We measured and drilled holes in the backboard and slid everything into place. Then we conducted a test — we held the funnel house in place and poured beans through it into the small arm. The arm filled, tipped, and dumped the beans over the top of the second arm sending them flying everywhere except into the mouth of the second arm, where they should have gone. We tried again, adjusting the counterweight on the first arm so that it would tip with fewer beans. The result was better, but it didn’t work nearly as well as it had with the chipboard. Why? The best explanation we could come up with was that the chipboard was providing some necessary weight and friction that we weren’t getting with the acrylic. (Unfortunately we have no photos or videos of this phase!)
After this fail, we decided it was time for a redesign. We’d struggled with the challenge of aligning the two arms through four iterations and it was time to face the fact that we might never get this mechanism to work properly. We went back to a design quite similar to our initial conception: an enclosed chute that moves the beans from the funnel house to the measuring cup receptacle.
Redesigning the mechanism meant we also had to rethink our circuit. We had intended for the moving arm to connect two components, therefore acting as a switch. With no moving parts this would no longer work. If at all possible, we wanted to incorporate sensors that could be integrated using our existing code or something very close to it. We settled on two flex sensors. Although analog, we could map them to 0 or 1 in order to replicate the data sent from a digital sensor. The enclosed chute had seams where the parts were fitted together and the flex sensor is thin enough to fit into that seam. The result is that the sensors are barely visible, which is nice.
After making this design change, we were able to progress fairly smoothly. We tested the enclosed chute with the funnel house and found that the beans moved quickly and easily from the funnel to the measuring cup. Almost all of the beans made it into the end receptacle, a huge improvement over previous mechanisms. We integrated the flex sensors into our circuit, measured the values, and mapped the data output to the 0 or 1 for Processing to read. Then we brought the circuit together with the mechanism and got it functioning.
Once that was done, we were able to work on the presentation of the narrative. With the redesigned chute, we had a nice open space on our backboard and we decided that would be a nice place to present the title, some data, and some contextual information. We thought for a while about how to bring more context and data back into the project. Initially, we’d based the project around state data, comparing foreclosure data in different states. That aspect was lost when we moved to the cantilever arm construction. We went back to the resources we’d initially collected and discovered that we had some nice points of comparison — peak monthly foreclosures, “normal” monthly foreclosures, recent (October 2012) data by state. In keeping with the homey theme and aesthetic of the project, we decided to present this information in the form of recipes and wrote out a few recipe cards that users would be able to read and use as a guide for operating the project. And we made the decision to put a “conversion chart” between the beans and the number of foreclosed homes in a picture frame.
One thing we didn’t have time to do was source better sound files and build out a more intimate listening experience. Our conversations about this project with residents and classmates reinforced the fact that individual stories were the most engaging element of the project. We’d tried to create an intimate experience, but we were asking people to listen from afar instead of leaning in and connecting with the storyteller. It would have been nice to have a bank of speakers, each one of which played an individual story. That way the user could pay close attention to one by leaning in close, or feel the gravity of the situation and become overwhelmed by standing back and hearing many voices at once.
Ideally, we would have had more time to think about and perfect the narrative aspect of the project. We ended up spending too much time wrestling with the moving parts and the interpretation of the data and structure of the narrative suffered as a result.
More pictures of the final build below. And here is our final Arduino and Processing code, in a PDF: PComp_Final_ArduinoAndProcessingCode.
The final project process was an intense learning experience. Some things I’ll be keeping in mind going forward:
- Understand exactly what the problem is and carefully evaluate the best way to solve it. In our case, there were two points at which we should have considered abandoning the moving arm mechanism: after unintentionally building a catapult and after building the chipboard model which only worked moderately well. A redesign at either of those points wouldn’t have had such an impact on the time available to build out the narrative.
- Make sure to keep the centerpiece of your project in the center. We allowed ourselves to push the narrative elements to the side because without a working mechanism and circuit, there would be no vehicle for the narratives. The end result was a working mechanism that didn’t carry much weight.
- Think through feedback and ask questions. We heard a lot of helpful things from our classmates, but we didn’t ask about the best way to implement those suggestions.