I got to try out a little bit of everything, again, this week. I had been trying to tweak an equation in the Arduino code for the temperature sensor since the middle of last week and finally got it to work – I think that’s pretty amazing considering the fact that I had absolutely no prior experience working with Arduino. Now, we can change the resistor values in the circuit, and the equation will account for these changes and output accurate temperature readings! Despite having to trek to the OEDK several times last week, I finally finished the control box for our study. I had the soldered perf board from last week, and with help from Danny at the OEDK, I was able to laser cut holes for the jack and USB port from a plastic project box. Now, we have a control box that’s ready to go for temperature accuracy testing!
In the Control Box
This week, I also started planning the Incubaby user interface (UI). Currently, incubators in hospitals here have different modes: preheat, warming, and wean. In the ‘preheat’ mode, the incubator is warmed so that it can initially provide heat. In the ‘warming’ mode, the baby is warmed, and the baby’s temperature controls the heating behavior of the incubator. Finally, in the ‘wean’ mode, the incubator decreases the heating power to monitor the infant’s response, preparing the infant to self-regulate his/her temperature. My job is to plan the UI layout; so far, it includes a display screen; a three-way control to select the incubator mode; and indicators for events like ‘overheating’ and ‘power loss’. It’s fascinating to see how much thought goes into designing a UI, especially for foreign clients. Do we use words or pictures, or both, to indicate the modes? What could the words/pictures be interpreted as? Are there particular connotations associated with the words/pictures of which we are and aren’t aware? As part of the UI, we decided that rotary selectors are much easier to use than toggle/slide switches. So I delved into the details of potentiometers and switches to see how they are similar and/or different. And, eventually, settled on using a switch to create a potentiometer. I can’t wait to experiment with that! Alongside that, I started to become familiar with Adobe Illustrator to prepare the UI front panel for laser cutting.
On top of that, I got a pretty thorough exposure to thermal interface materials (TIM). We think we can improve the contact between the thermistor probe and the infant’s skin by using TIM. After extensive research, I found that stickers made of hydrogels and hydrogel colloid are currently used for this purpose. So, for almost 2 whole days, I researched several vendors who sell either hydrogel sheets or gel and requested samples from all of them. I have yet to obtain prices from any of them but hope to find materials that will keep the entire device cost-efficient.
I’ve been doing a lot of prep work and research for the coming week. I can’t wait to begin experimenting with the switches and TIM samples and laser cutting for the UI!