This paper presents a novel approach to real-time length sensing for biomimetic Braided Pneumatic Actuators (BPAs) in soft robotics applications. Flexible strain gauge sensors from LiquidWire are ironed onto a sewn Nylon sleeve for external placement on BPAs. Calibration equations that include voltage rate and hysteresis are developed to convert strain gauge resistance into muscle displacement. Experimental results demonstrate the efficacy of the proposed method, achieving low error rates and high biomimicry. The non-linear calibration outperforms linear methods, showcasing its suitability for artificial proprioceptive neural networks. This approach offers accurate real-time feedback for enhanced robotic control, addressing the need for low-profile, modular sensors that mimic muscle stretch receptors. Future research may explore further refinements and applications of this technique.