The semester is winding down, so everything is getting a little crazy. I spent the last week working on my midterm report and midterm presentation. Also I worked on assembling more Sharkduino V2.2s. I haven’t really had a chance to do any new work around that so there is not much for me to write about this week. Next week will be my final post for the semester and I will try to go over what I did this semester and what I hope to achieve next semester.
The first thing I did this week was begin a Sharkduino battery test. I connected a V2.0 to a 850mAh battery with the latest code for that system. As of time of writing (04/18/17) the tag is still on and recording data. This is great and means that our battery life on the 850mAh battery is better than the 1 week we expected.
The next thing I did this week was assemble three more Sharkduino V2.2s. I did all three at the same time for these. I am experimenting right now to see if I can decreases the time to build each tag by building multiple at once. This seems to be going great, I have gone from 2-3hr per tag to close to 1-1.5hr per tag by doing multiple tags together. On this set of three I did make a mistake on one of the tags and break the battery slot for the RTC coin cell. I am going to try to jerry rig a fix. That tag will not be fit for deployment however, and we will use it for code development. I will continue working on assembling more V2.2s in the coming week in an attempt to have 10 ready for deployment over the summer.
The next thing I did this week that took a lot of time was countered work on my honors midterm report. It is coming together well and I should have it done next week.
Finally this week we did a code hardening sprint. This is when we stop developing new features for the code and test it extensively to find and fix all bugs in it. We did this so that we can insure that we will be getting good data and the tags will work over the summer. This is extremely important because the summer is the only time we have access to live animals. We need to insure that we can collect good data during this time period so we have more realistic data to analysis over the coming semesters.
This code hardening took a long time as we have 3 version of the code to support. One version for the Sharkduino V1.0s, one for the V2.0s, and one version for the V2.1s and V2.2s. The hardware differences between the V2.1s and V2.2s are minor and have not been utilized in the code yet so these two version can run the same code. The process of hardening the code was long and tedious. There are a lot of steps in the code, first tag configuration, then the data taking code, then the parser, and then the importer to R and the basic R analysis. We were not trying to harden the R analysis this week but we still needed it to test the other portions. Every time we found a bug in the code we would then need to test every step that came after it again to make sure both that the bug was fixed and that we did not accidentally introduce a new bug further down the line. After nearly 10 hours of work with the team we did finish hardening all the needed code, so we are now ready to take data over the summer. I will however be doing another battery of hardware tests once I finish assembling the V2.2s
I did a lot of work on the project over the last week, but not tons that will be very interesting to write about.
First off all the parts for the Sharkduino V2.2s came in. I invented everything and started assembly. Since I need to build so many of these I am experimenting with more batch assembly. The problem is even though making more than one board at a time decreases the time per board, it still increases the total time I spend working on them. This makes it harder to fit board assembly into my schedule. I am still doing some things that have really speed up board assembly. The first is that I have been soldering the uSD card onto the boards on different days then I do the rest of the components. This both splits up the assembly time, and gives the oven more time to cool, which gives a more regular heating curve and better solder joints. Also I am getting better at using the solder stencil, that combined with the new steel solder stencil is helping a lot. Finally the Sharkduino V2.2s just have fewer components on them because they don’t have the charging circuit, and perhaps more importantly it has fewer different components. I have found that switching between placing components has a much larger impact on the assembly time then just the raw number of components on board.
In addition to the Sharkduino V2.2 work we had a phone call with an engineer at NASA. We talked about IMUs and analysis techniques. We learned a lot of great information that will really help to move the project forward.
Finally I am still working on my midterm report which is due near the end of the semester.
I have a lot going on this week, and did not do super interesting work on the project last week, so this will be a very short post.
First I finished up placing the orders for the Sharkduino V2.2. Everything is on it’s way and I will probably start assembling Sharkduino’s in the next week or two. Next I did more research on how to handle our LiPo charging. I’ve been looking at power path circuit chargers and right now I’m a little confused about what I want to do. Once I understand what I’m looking at and what I want a little bit better I will post more about this. Finally I began work on my honors research midterm report. This is the first step toward writing my honors thesis, so that is very exciting. I will make sure to post the final report on this blog once it’s done.
The big push this week was to get the Sharkduino V2.2s ordered. I finalized the designs, assembled the shopping lists and began the process of getting everything bought. This took longer than normal because I am buying parts to build 12 new Sharkduinos, and as such this is expensive and it is important I get everything right on the first try.
In addition to ordering, I got some work done with the heat shrink waterproofing. I finally got the heat shrink tests I put in VIMS back, and everything worked out great. We put 3 tubes with paper towels under the water, and floated a fourth tube with a Sharkduino taking data on the surface of the water. Everything stayed dry and we got some good data from the floating shark duo. Additionally the Sharkduino collected data for approximately 7 days giving us a true proof of the concept that the device works as intended outside of the lab.
Finally this week I assembled a new Sharkduino V2.1. This finished off my parts from my last order of Sharkduino hardware, so I am waiting on the new stuff to come in before anything else comes in. I also got lucky on the build. Two of the pins on the gyro ended up with a solder bridge between them, but they are no connection pins and them being shorted does not seem to be affecting the gyro. This is the first fully function Sharkduino V2.1, as the last one had problems with the gyroscope that made it unusable.