Posting on Tuesdays is feeling pretty good for these updates so expect this to continue during the semester.
I began this week by finally getting prototype 5 operational. This is not as exciting as it sounds because I only fixed some of the problems it was having. The other problems seem to have gone away on there own, this is very troubling as any problem you don’t fix isn’t fixed. I tried to recreate the problem I was having but I couldn’t so the only thing to do now is to use it and pay close attention to see when it will fail again.
In addition to this I began work on a design overhaul of the sharkduino layout. I am working on putting the existing sharklion components onto a single board. This board will be larger than the stackable boards but since there is only one I am working with a slight decrease in overall surface area to populate. This new board currently has a trapezoidal shape to hopefully mirror the shape of the fin it will be attached to.
Finally I began work on finding a new RTC chip. The chip we have right now is physically large, expensive, and uses SPI, which is has been hard to work with because the uSD uses a different mode of SPI. Switching between these modes has been a problem for us in the past. Because of this I am looking for a RTC that uses I2C, is more power efficient, is physically small, and cheaper. Now this sounds like a lot but our current chip has a lot of features we are not using so we can make a lot of concessions to achieve these goals. I thought I had found a chip that satisfied all these criteria, and I got as far as completing a PCB design schematic for it before I realized that it uses slightly more power than our current RTC. It does fulfill the other criteria we were looking for, but our current chip already uses a fair bit of power and increasing the power even for the other gains does not seem like a good deal right now. Established since there seem to be a fair number of other chips on the market that can fulfill all the goals, they just have fewer publicly available PCB designs associated with them. I spending so much time with a chip that ultimately will not work is a screw up but I have learned what to do to keep it from happening so hopefully I won’t waste a big chunk of time this way again.
I’m making this update because I feel I was being a little down about the RTC thing when I wrote this post. I have actually done more research into RTC chips, and while the one I designed for may not have been the best chose, it isn’t the worst. So I’ve decided to go forward using it. I will probably replace it again at some point in the future but it gives us enough gains to use for now.