Development of a BLE-Based Multi-Channel Measuring Instrument for Gas Desorption Indices in Coal Drill Cuttings

The gas desorption indices of coal drill cuttings are critical parameters for predicting outburst risks during coal seam exposure in shafts and roadway excavation. To address the limitations of existing instruments, such as low informatization, operational complexity, slow measurement speed, and incompatibility with drilling construction rhythms, this study proposes a multi-channel coal drill cuttings gas desorption index measuring instrument based on Bluetooth Low Energy (BLE). The system adopts a distributed architecture to implement a master-slave collaborative mode, consisting of an intrinsically safe handheld terminal and multiple measurement chambers. Each chamber integrates pressure sensors, a weighing module, and BLE communication, enabling automated measurements of Δh? and K? values independently. Data interaction with the handheld terminal is facilitated through unique MAC addresses. The hardware system, designed around the ESP32S3 microcontroller, incorporates a touchscreen, high-precision weighing, power management, and sensor interfaces to automate measurement workflows, achieve real-time data storage, and support wireless transmission. Test results indicate a standby power consumption of 306.2 mW and an operational power consumption of 706.7 mW, with continuous operation exceeding 10 hours using a 1600 mAh intrinsically safe battery. Comparative tests with traditional instruments reveal maximum relative errors of 7.94% for Δh? and 6.89% for K?, demonstrating high accuracy. By optimizing time control and coal sample weight calibration, the system significantly reduces human error while enhancing measurement efficiency and reliability, providing an advanced technical solution for predicting coal mine outburst risks.