Schematic? Check. Parts ordered? Check. Caffine? Check. In the last two weeks of the Great Global Hackerspace Challenge, i3Detroiters start to piece together the real working guts of the Interactive Quiz - our group student response system.
In our video update this week, Roger Slykhouse, Ed Platt, and Ross Smith piece together some of this week's obstacles, achievements, and little victories.
As Roger discusses in the video, our team's collective design brain settled on a plan for the group response system. By degrees, the plan became more articulated and informed as we baked it down into actual hardware requirements. From there schematics were assembled for the two response modules - the teacher unit and the student units. This made it possible for us to write software to verify the schematic. As Ed describes in the video, we did our utmost to find areas where work could be done in parallel - project case design, schematics, software, documentation, and so on. This would allow us to work on all fronts of the project possible, so long as we didn't encounter a process bottleneck that hung up every aspect of our work.
Here is where our real challenge began. To build the final project enclosures, we needed the final dimensions of our printed boards. To get the design of our printed boards, we had to finalize our schematics. To finalize our schematics, we needed to author enough software to test the schematics and verify that all was laid out correctly and that our hardware choices are good. Testing our software means we needed to get two radios talking to each other.
We hit the process bottleneck we were nervous about in the form of software. Getting the MRF24J40MAs to talk to each other proved to be a challenge, especially given the steep learning curve most of our software team had to overcome. Most of our software team have slim to no experience with microcontrollers. Thus our embedded systems experts were busy tutoring the learners, getting them to the point of being equal to the task at hand. This gave the team less time to disentangle some of the critical software issues that held up the rest of the project.
Thankfully some members of the open source wireless community answered our calls for help and offered some pointers. Another hacker on the Internet was modifying the Chibi stack to use - as luck would have it - our project's microcontroller of choice! With a fresh code checkout of this developer's Chibi stack code and a photo of his breadboard, Paul, our team's embedded programming expert, set to work on the radio communications code and the state machine, thus far to good results.
In tandem, a wired prototype of the multi-student response system was created practically overnight - one which cuts out the troublesome radio layer entirely by wiring three student response units to a single teacher's unit. This allows the teacher to set question answer states, give students time to answer, and observe the results. We will do more testing with this wired prototype in week 6 and we'll be sure to update you on the state of the true wireless prototype.
Until then!