It's Mackenzie again,
Today we reviewed Sprint 2 as team, focusing on what went well and what could have gone better. As you can see in our "delta plus chart" below, we had a lot to talk about. As a team, we agreed we were proud to meet our sprint goal: a one-marker machine that intentionally draws a spiral. The video is  below. 
We also agreed that we need to change how we weight work throughout the course of the sprint; the majority of work in Sprint 2 was done in the last two days. This lead us to our kaizen: "Always know what you're working on and work on it." We plan to fulfil this, in part, by commiting a full 12 hours a week on our project, having frequent all-team standups where we present our work, have more frequent meetings, and front-load the majority of sprint work. We also plan to commit the last 15 minutes of all team meetings to documentation. 

Kai here--

​We decided to use python to pre-process images, since an arduino won't be able to do that on it's own, and devised an concise instruction set to sent commands from our python program to the arduino. Because we are going to link the rotation of our wheel with the displacement of the markers along the radius (like a spiral), we are able to create simple commands as follows: [radius], [state], [marker].

Let me break that down a little bit. The first element, the radius, will be some number of degrees which is the total amount of rotation the wheel has spun. As I stated earlier, the rotation and displacement will be linked, so we can get the exact position of the marker from just one number.

The second element is the state of the marker. This is a binary, 0 for up and 1 for down. The marker will assume that state, and hold it until it receives another command.

​The final element is the marker indicator. Because we plan on using three separate markers, we need to indicate which marker we are actually manipulating, with an integer from 0 to 2.
This set of instructions is sorted by radius so that we can send the commands in the order that they will be followed, spiraling from the inside out. They will be sent over serial communication to the arduino, and not all at once so as not to overload the controller with data.