This week started with me getting oriented and easing myself into working on the project full time. I started the week with some high level project planning. I sketched out everything that I believe needs to be accomplished in the project and then broke those goals into actionable steps to achieve them. Hopefully this will give me some structure to the summer and help me figure out what to working on when.
Next I did some training. In addition to continuing to work on getting the certifications I need to work with live animals I took a short online course to learn Eagle and the basics of PCB design. Eagle is a free software package for designing PCBs, which are printed circuit boards. Basically they are a good way to manufacture electronics. Currently the devices are made out of a lot of commercially available PCB boards with the necessary components attached soldered together with wire. If I design my own PCB boards I can put all of the parts in a form factor of my choosing and remove parts for the commercial boards that I don’t need or don’t want for some reason. This means using Eagle I can design smaller more efficient circuit boards for the project.
In addition to learning new skills I also tested some new components for the project. These include a GPS and a gyroscope. The GPS is for a part of the project that I have not discussed very much on this blog and that is recovery of the device. Once the device has taken data we want it to separate from the shark, surface, and then be retrievable by researchers in a boat. To do this we need a way to locate the device and one way we are looking at doing that is through GPS.
The gyroscope is for a part of the project that I have talked about at length on this blog and that is the removal of gravitational data from the accelerometer data and determining the orientation of the board. A gyroscope is a device that measures rotational motion, in the case of the gyroscope we have it measures degrees per second. It can essentially tell us the orientation of the device, and since the direction and magnitude of gravity is know we can basically just subtract it from the data set with no real problems. This gets us around the issues with trying to filter gravity, such as the imprecision and the problems introduced if the animal rotates in certain ways. The big downside to adding a gyroscope is power and memory, it needs to read data at the same rate as the accelerometer and needs to store data about three angles, this doubles the amount of data being taken at recoded at the 8Hz frequency. However we believe that the improvements that the gyroscope gives us are worth this steep cost. You can see a picture of my set up for testing the GPS and gyroscope below.
Finally this week I have been working on layout and starting the next prototype board, this one incorporating the gyroscope. For this board instead of using the point to point wiring method I have used in the previous prototypes I am using a solderless breadboard and this is taking a lot of layout planning. I want make this prototype as compact, long, and narrow as possible and I have spent a lot of time laying out the board and mapping the route that connections will take. Even though I did learn Eagle this week I have been using some less sophisticated hardware for this purpose, since Eagle is not well suited to this sort of layout work. You can see my nearly incomprehensible design below, hopefully I will be able to show you the real thing next week.