Hello everyone, my name is Andrew Kistler, and I am spending my summer in Golden Colorado at Colorado School of Mines. For the next seven weeks, I will be working in the M3 Robotics lab with Dr. Andrew Petruska as well as some graduate and undergraduate students.
This week we continued to try and prepare the gantry system for its first test.
Unfortunately, like last week, we have continued to have issues with the gantry. An issue that needed to be fixed was the encoders, which communicate with the motors about location, speed and other things, suddenly had volatile memory. Volatile memory means that whenever the system loses power, it forgets everything and an example of this is the RAM in your computer. What we need for these encoders is for the memory to be nonvolatile, like a hard drive or SSD in your computer. We eventually figured out the issue. Basically, when we turned the power on for a test, it somehow swapped the mode on the encoders from nonvolatile to volatile. We were very happy to find a solution because, without it, we would have to reflash the encoders every time we turned on the power.
Encoder mounted on the carriage
We also had an issue that we were unfortunately not able to solve this week with our limit switches. Our limit switches serve as a fail-safe. The gantry shouldn’t and isn’t supposed to reach the end of its tracks for safety reasons that I’m not aware of. So, if one of the limit switches is pressed anywhere on the gantry it will require a system reset before the gantry is able to move again. The issue we were having is that whenever one of the limit switches was pressed it would go through a cycle of being on and off seven or eight times. So, whenever we pressed the switch once, the computer thought it was being pressed seven or eight times. We initially thought that this was a hardware issue, but after checking the limit switches and connections with a multimeter, we continued to have the same issues. So this is likely a software issue, and unfortunately we were not able to fix it this week.
Limit Switch
I also spent some more time working on my water alarm project. One of the electrical engineers taught me how to use a program called Eagle CAD. This program allows me to make a prototype schematic for my PCB. This project is much more difficult than I initially expected as there is a lot to learn, and it is quite a steep learning curve.
Water alarm schematic
Because of the fourth of July, I had Thursday and Friday off, so I was able to go home and celebrate the fourth with my family. It was great fun to see my family and my friends for the first time in five weeks. 
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