Local gravitational acceleration is a key parameter in force calibration, nsuring accurate conversion from mass to Newton (N). However, calibration laboratories often face limited access to accurate local gravity values at measurement sites, necessitating a measurement device capable of providing direct and precise gravity readings.
This study presents the development of a local gravity measurement prototype using the free-fall method within real-time display of measurement results on an LCD screen and Blynk application. The prototype is designed with a vacuum enclosure connected to an air pump to minimize environmental interference, and employs the HX711 module for precise sensor signal acquisition. Development follows the ADDIE method, including needs analysis, design, construction, implementation, and evaluation. Validation is performed using ASTM E4-21 and manual Free fall (GJB) methods with a stopwatch, and tests were conducted at five locations in the Greater Jakarta area.
Measurement results show local gravitational acceleration values ranging from 9,77179 m/s2 to 9.77971 m/s2, with an average absolute error of 0.00087 m/s2 relative to reference values. These data demonstrate that the prototype offers stable and accurate performance, while facilitating easy access to measurements via a digital application. This device is a viable solution to support the accuracy of force measurement calibration in laboratories.
Keywords: Local gravitational acceleration, force calibration, ASTM E4-2!, vacuum enclosure. Free fall method