Swift, Modbus TCP, Objective-C (bridging)
WET SKIDMETER
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CONTEXT
Three times every day, the chemist takes a sample from the water skid, measures it in her lab, then returns to adjust the skid if needed to maintain the water for fountain demos. The skid and the lab are on opposite sides of campus. I was told to make an iOS controller that fulfilled two goals:
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a) Include a calculator to replace a complicated, error-prone spreadsheet
b) Build a controller to turn the bromine flow on and off for daily cleansing.
USER STORY
Supervised by Senior Chemist Grazyna Orzechowska, I maintained the water skid for 4 days before I started working on the app.
Difficulties I encountered:
1. It was easy to accidentally change vital parts of the spreadsheet.
2. Sampling the water and adjusting the skid took two trips across campus, carrying a computer (for viewing the spreadsheet).
"Easy to accidentally change vital parts of the spreadsheet."
"... adjusting the skid took two trips across campus."
DESIGN PHILOSOPHY
The overarching design philosophy was to reduce user friction and improve workflow with a very simple design.
Skid maintenance consumes an hour every day, and the process was fairly monotonous. I decided that color-coding would not only help the user associate numbers with labels, but reduce eye strain in reading values.
MEDIUM-FIDELITY PROTOTYPE
Auto-calculates with inputs after 1.8 sec
Minimizes handling phone with wet hands
Extra-large, uneditable font
Guarantees calculation without error
"Auto": turns skid on and off for you
Great convenience, but sensors become inaccurate overtime, so manual adjustment still a necessity*
*Solution: make the range adjustable; sensor inaccuracies were always off by a known amount, so we need only shift the acceptable range.
END-PRODUCT
Implementation
After finishing the assignment 10 days early, I remade the color scheme so that the screens would be connected by way of the white background. I also did this because we would use our phone screens as flashlights in the dark skid room, and the white background helped it serve this purpose.
Future Considerations
Given more time, I would have added a button to turn on the flashlight on the back of the phone. This way, should we desire a brighter light in the garage, we wouldn't have to open the flashlight app at all; this would be especially beneficial for iPhone users compared to Android users due to lack of navigation buttons. Additionally, it would have allowed us to make the app dark-themed, which would have resulted in less eye strain from looking at a bright screen in a dark room.
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