Autofeelment: Design and Development of an Automated Monofilament Testing Device for Peripheral Diabetic Neuropathy

Abstract Peripheral diabetic neuropathy is a common complication of diabetes mellitus and is associated with progressive loss of protective sensation in the feet, increasing the risk of ulcers and lower-limb complications. The Semmes–Weinstein monofilament test is widely used to assess protective sensation; however, variability in manual administration may affect consistency in test delivery across settings. This study presents the design, development, and mechanical validation of Autofeelment, an automated device intended to standardize the application of the monofilament test through controlled actuation and sequencing. The device consists of a mechanical platform with four linear actuators, a microcontroller-based control system, and a smartphone interface to enable automated testing at predefined plantar locations. Mechanical validation was conducted using healthy volunteers to assess timing consistency, actuator performance, and usability. Ten participants each completed three consecutive testing trials, resulting in 30 validation trials and 120 actuator extensions. The device demonstrated a mean testing time of 10.409±0.019 s, corresponding to a coefficient of variation of 0.18%. Successful monofilament buckling was achieved in 118 of 120 actuator extensions (98.3%). Participants reported high levels of comfort (mean 4.6/5) and ease of use (mean 4.8/5), with no adverse events observed. These findings demonstrate the mechanical reliability, temporal consistency, and usability of the Autofeelment device as a prototype system. This study does not evaluate diagnostic accuracy or clinical effectiveness. Further work is required to validate automated monofilament testing in diabetic populations and to compare performance with standard manual testing methods.