Issue link: https://iconnect007.uberflip.com/i/1108006
38 FLEX007 MAGAZINE I APRIL 2019 added no significant stiffness to the Smart- Patch. Spatial packing of the electronics was very efficient. Asymmetric through holes were designed into the edges of the board to facili- tate mounting in a pogo pin test fixture. The electronics are a completely self-contained remote monitoring platform. Once encapsu- lated, there are no physical connections with the outside world. All functions, including test- ing, data telemetry, status monitoring, param- eter updates, and over-the-air-programming (OTAP), are done wirelessly. As a cash-strapped startup, it was important to manage some of the risks during develop- ment. There is always a tradeoff between the efficiency and cost per unit of a large batch run and the risk of committing those resources to a design that had yet to be verified. Before run - ning the first lot at Lenthor on the customized platform, a small quantity was run through a standard, quick-turn process on FR-4. Being completely rigid, these units were not suitable to be molded and placed on a patient's arm, but running a relatively inexpensive, quick-turn version let us debug the schematic and layout. They were also invaluable as development tools. As a nearly final version of our prod- uct, the embedded team used them to finalize development of the firmware. Also, the test- ing group used them to bring up and finalize our testing systems. Performance and function were validated against benchtop models with a high degree of confidence that they would function nearly identically to the final flex product. All this pre-run activity primed the company so that there was a minimal delay between receipt of the final flex product and our ability to start manufacturing. No discussion about a product develop- ment experience would be complete without mentioning quality. Almost all industries have norms for quality assurance. Manufacturers of medical devices are governed by ISO 13485, and wearables fall into this category. There is, however, a lot of commonality with other standards. Before committing to our first run at Lenthor, our quality team reviewed their qual- ity system governed by ISO 9001 and verified that all of the requirements under our quality system were satisfied by Lenthor's procedures. The Lenthor flex circuit is molded into a sili- cone device (Figure 3) that can be applied to the AV fistula of a patient and capture clini- cal data remotely, whether from their home, at their workplace, or even while in a dialysis clinic. Once a device is placed, it automatically monitors for seven days, sending data back via the B2H medical relay. Figure 2: Final electronics assembly for molding into the GraftWorx SmartPatch.