Due to scheduling reasons and the thanksgiving break I am doing a strange week and half weekly update.
I began this week by testing the current draw between the new and old gyro. The new gyro pulled a little more than half the current of the old one. So on a power consumption basis the new gyro is a big win.
Next I decided which uSD slot to use. To do this I put uSD cards into each of the slots. I then tested to see how hard it was to pull the SD out. Next I through the slots on the ground and against the wall. This is a rather crude test but did give me insight into how tightly the slots held on the card. I was ultimately able to make a decision and incorporate the new slot into the designs for the new sharkduino.
I then tested the charging circuit on arduino V1 Layer 2. I had not been able to get the LED to light up properly during the summer when I built these. Now I went back and tried again and was able to get the LED on properly, it turns out I had the surface mount LED backwards.
Finally this week I finished the designs for the Sharkduino V2. I have sent it off to be printed and will give more details about it in the coming weeks. For now know it has an all new form factor, the new gyro, the new RTC, and a new uSD slot. In addition to ordering the boards I also ordered solder stencils for this design. This should hopefully make assembly much faster and less error prone.
I spent a lot of time coding this week. I decided to try to figure out sending data from the uSD card to a computer over bluetooth. I already had code to send data over bluetooth and to read a uSD card so I really had to do was combine the code. This doesn’t sound very hard, and in the end wasn’t, but took a while because I did not understand the bluetooth code as well as a thought. Eventually I was able to read a string of text from the uSD and then send it to my phone via bluetooth, which received it as ASCII code. I decided that was close enough and moved on to trying to do the same thing with one of our DATA.SRK files. I was working but the transfer was super slow. I think I was running into a problem with how I was using bluetooth, and not the data rate of bluetooth itself but I still need to check.
At the end of the week I moved bluetooth coding back to back burner because my order of PCBs came in. I got some more layer 3 boards, a board for testing the different uSD slots I’m looking at, and a breakout board for the new gyro. I began by assembling the uSD test board. I found 2 of the slots worked, and the 3rd did not. I assembled a second test board for the non working slot and it still did not work. This means the problem is with the slots or the design and not the soldering. Instead of troubleshooting the slot I am just going to chose between the two working slots for placement on the sharkduino.
uSD test board
Finally I assembled the gyro breakout board. This was hard to do since the gyro uses a very small package, but in the end I got it to work. I does however not have the expected I2C address and I have not been able to determine if the data I’m getting from it is actually good. That is a problem for next week. For know all I know is that it sends and receives data.
New gyro breakout board
I began the week by ordering the PCBs for the new gyroscope and test boards for the uSD slots. Those will probably come in the next week or two, so I pick that development back up then.
In the meantime I have been working on creating a sharkduino for software testing. The different models of sharkduino have slightly different sensor packages right now, and no model has the temperature and pressure sensor integrated in. This is sort of a problem for the software development because we want to make sure everything works well and plays nice with everything else. To solve this problem I spent the week putting together a sharkduino on the breadboard so that we can easily switch out sensors and quickly keep it up to date with the newest breakout boards. While the point of the breadboard is to allow for fast prototyping it did take awhile to get the breadboard sharkduino put together because I had to do a lot of surface mount to get more breakout boards to attach to it. I had to assemble a gyro and RTC breakout board. Then I had to lay everything out on the breadboard and test everything. A picture of the breadboard sharkduino can be seen here. All of the purple PCBs were designed and assembled by me.
Once I had the breadboard sharkduino assembled I began to write code to transfer data off the SD card and sent it to a computer via bluetooth. Right now the code compiles but I have not attached the bluetooth module yet so I do not know if it works. That is one of the projects for next week.
Finally this week I did some research into how to waterproof temperature sensors and the charge and discharge rates of Lipo batteries. No week is complete without a little bit of miscellaneous research.