Closed-Loop PBM Output Regulation on Raspberry PI for Safety-Critical Home Devices
DOI:
https://doi.org/10.63282/3050-9262.IJAIDSML-V5I2P124Keywords:
Closed-Loop Control, Raspberry PI, Photo- Biomodulation, Real-Time Systems, Embedded Control, Safety-Critical SystemsAbstract
Photobiomodulation (PBM) devices employing light- emitting diodes (LEDs) are increasingly adopted for home and clinical applications due to their low cost and compact design [1], [2]. However, many low-cost PBM systems operate in open-loop configurations, resulting in output drift caused by temperature fluctuations, supply voltage variations, and component aging [3], [11]. These deviations can lead to inconsistent optical dosage, raising concerns regarding safety and reproducibility [4], [5]. This paper presents a Raspberry Pi–based closed-loop PBM output regulation system that continuously monitors optical intensity and device temperature, dynamically adjusting the drive current using a proportional-integral (PI) feedback controller [6], [7]. The proposed architecture integrates real-time sensor feedback, adaptive control logic, and software-enforced safety interlocks to maintain stable optical output within predefined bounds [8], [9]. A diffuser-based experimental test rig evaluates system performance under thermal and voltage stress conditions without involving biological testing [11], [12]. Experimental results demonstrate a significant improvement in output stability and response time compared to open-loop operation. This work illustrates how low-cost embedded platforms can implement safety-critical closed-loop regulation for home PBM devices and similar optical systems [10], [13], [14], [15].
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