Design and validation of a low-cost, low-power, clockwork insulin pump

Abstract

A novel, low-cost (≤ NZ$500), and low-power (12 month estimated battery life) insulin pump prototype is presented. The device aims to increase insulin pump uptake by offering a 9-17 times reduction in pump cost, by limiting the inconvenience and economic constraints of pump treatment. Low-cost is achieved by offloading computation from the pump to a smart device via Bluetooth. An innovative pumping mechanism enables long battery life, with all power required to deliver insulin provided by a spring. A clockwork escapement mechanism is integrated with a low-power actuator to provide dosage control. The accuracy of the novel design was assessed using in-vitro testing to IEC Standard 60601-2-24 (2012) and was benchmarked against two commercial insulin pumps. The clockwork pump achieves similar accuracy to the commercial devices for boluses of 0.005 ml, 0.01 ml, and 0.05 ml, with mean errors < 5%. Consistent over-delivery reduces the accuracy of the clockwork pump at the minimum bolus volume of 0.001 ml (8.1% mean error). For all basal rates tested (0.001 ml h−1, 0.005 ml h−1, and 0.01 ml h−1), the clockwork pump demonstrates similar accuracy and improved consistency compared to commercial devices. Redesigning with higher precision hardware will improve pump accuracy, enabling comparable performance to commercial pumps across all boluses and basal rates. The standards-based testing validates the novel pump concept and justifies further development.