Happy belated State Rebellion day! In the state of São Paulo, July 9^th is a holiday celebrating the state’s 87-day fight against the 1930 coup d’état. Last Monday, the hospital observed this state holiday with a day off, which means last week was a four-day work week. The number of days we have left in Barretos is winding down, but our projects are speeding up, making those four days jammed packed. Both Georgia and I are at the point in our projects where our ideas are taking physical form and meetings with project idealizers are becoming more frequent.

Last I wrote, I was finishing up electrical troubleshooting and about to begin the physical construction. With my notebook drawings and rough digital designs, I talked Hiago through my plans. I went into the meeting expecting him to show me tools and materials I could use from the woodshop in the neighboring office. Instead, Haigo told me I can send detailed drawings for construction to the hospital’s factory where they create the mobile units. I think in that moment, my eyes actually lit up. My woodworking skills are on par at best, and a professionally crafted body will make my project look more professional.

The next morning, I began working on SolidWorks, a drafting software, to digitize my plans. It’s been preached to us time and time again in our engineering classes that strong documentation is essential. I could have drawn out my design neater and added more labels, but I wanted to make sure there was no ambiguity in the plans. In SolidWorks, every single dimension has a measurement value, the device can be viewed from any angle, and texture can be added to the surfaces to demonstrate different materials. Next week, those parts week move from being saved on a computer to sitting on a table.

Just like how I want the manufacturer to know what I’m trying to convey through my drawings, I want the clinicians to know what I’m trying to ask through the screen’s text. My device asks the user questions like “How many mL are in the vial?” and confirms their inputs with statements like, “You entered ___ mL, correct?” Later that same day, I met with Dr. Wilson to talk through the user experience. We went through each screen discussing the purpose of the prompt, the amount of time spent on the screen, and the display of values.

With each suggestion Dr. Wilson made, I would adjust my code, re-upload it to the Arduino, and run it again for him to see the change. One of our changes was exchanging the word garrafa, which is like a soda bottle, for the word frasco, which is a bottle of solution. Google Translate couldn’t distinguish between the two words for bottle but asking a clinician about the mL in a garrafa would have been confusing. Another thing Dr. Wilson had concerns about was the representation of decimal values. The US uses a period to represent a decimal, but Brasil uses a comma. When the screen displays 2.000 mL to represent two mL, a clinician may read that as two-thousand mL. Also, commas show up on the screen as little letter I’s so even representing two as 2,000 is not entirely clear. To resolve this dilemma, we removed one decimal value from the displayed number so two mL is shown as 2.00 mL and will include a disclaimer in the user manual, clarifying the notation.

There will be some more tweaks and edits in my code down the road, but after meeting with Dr. Wilson, I finally had the courage to solidify the electronic connections. Soldering the accessories to the Arduino could be undone, but the idea is that soldering fixes connection in place, so there are no faulty connections that could disrupt functioning. I wrapped up the week in Clinical Engineering soldering the screen to the Arduino. Two and a half hours later, my computer schematic matched the hardware sitting in from of me, and I powered up the Arduino for the moment of truth. The first user prompt flashed across the screen and I sat back in the chair and exhaled, not realizing that I had been holding my breath.