This summer, the DtM team passed a major milestone in the development of the Otter Warmer: the design and fabrication of our alpha prototype!
Otter is a durable, washable warming bassinet for premature and low birthweight newborns in developing countries. The alpha prototype is the prototype iteration to both look like and work like our expectations for the finished product.
The Otter alpha prototype includes two key new features: a numerical user interface and a heating assembly manufactured from a translucent polymer film.
At the beginning of the year, the DtM team brought the Otter warmer prototype to Vietnam for user design reviews at hospitals around Hanoi. This user feedback validated the need for the Otter warmer, and suggested some important design changes around the user-interface. For example, users specified that they wouldn’t trust the user interface without a numerical readout of the set temperature and current device temperature.
The Otter alpha now features a large, bright LED segment display that alternates between the user-set device temperature and the current device temperature. The user interface mirrors the design language of the Firefly phototherapy device. The elements of each interface panel are similarly aligned which makes the user interaction with both devices more intuitive.
In January and again in June, DtM volunteers conducted a series of Otter design reviews with partner MTTS in Hanoi. This included a manufacturing study of the Otter heating element. The original prototype used nichrome wire embedded in a CNC-milled channel in the base of the polycarbonate bassinet. Manufacturing research suggested this would be a prohibitively expensive fabrication process with a high part rejection rate. The heater assembly accounted for $50 out of Otter’s $180 bill of materials (BOM).
Our new alternative, the PTF heater, is similar to the heater wires you might see embedded in your rear windshield as a defroster. It is manufactured in a single step used for generic flexible circuits, and would allow us to more easily incorporate thermal sensors and other components. The PTF assembly would be applied to the bottom of the Otter as a semi-transparent sticker. Our current cost estimate for the new PTF heater assembly is roughly $20--more than a 50% cost reduction!
Stay tuned as we bring the Otter alpha overseas for user-testing in Africa, and for another manufacturing review with MTTS in Vietnam and outsource manufacturing vendors in China!