An angled ruler is a triangular ruler with one corner of 90 degrees. The measuring angle is one of the most important tools in carpentry which is often used in basic work and also when measuring parts that are closely related to the angle of the material and space to be worked on. As a measuring tool, the Angle Ruler must be calibrated periodically. One test that can be carried out is by comparing the standard Dial Indicator reading from an Angled Ruler to a Granite Square. Current calibration of angle rulers in Indonesia is still done manually. In manual measurements, there are currently doubts due to the less stable vertical movement of measuring points and the absence of a distance reading tool that shows how much distance has been moved at each test point. Calibration Measurement Capability (CMC) is the best capability of calibration results possessed by the Calibration Laboratory which is represented by the Uncertainty value at the 95% confidence level (U95). The smaller the CMC value, the better the calibration carried out by the calibration laboratory. Calibration carried out manually is less stable in position and distance, resulting in reduced accuracy values and greater CMC values. By utilizing a microcontroller, and a stepper motor driver and then commands using the Ardiuno IDE language using the HC- SR04 ultrasonic sensor, this research designed a Position and Distance Stabilization Tool for Calibration of Angled Ruler Using Standard Granite Square Tools and Dial Indicator at PT Sentral Tehnologi Managemen. The height of the tool that can be used is 370 mm. During the test, 5 repetitions were carried out at positions (100, 200, 300, 370) mm, which is the measurement capacity of the standard Granite Square tool. The results of the tests that have been carried out show that the data obtained from manual calibration of the Angle Ruler has the smallest uncertainty, namely 3.8 μm, while the data obtained from calibration tests using tools obtained the smallest uncertainty value (U95), namely 3.2 μm. So that the uncertainty (U95) of the tool is smaller than the uncertainty (U95) of the manual, it can be concluded that this tool helps stability and position during calibration. Apart from that, the accuracy value using the tool is better because the correction value is smaller, namely 5.9 um compared to 32.2 μm manually. This is because the repeat measurement value using the tool is more stable and precise so the correction value is smaller.
Keywords: Angled Ruler, Calibration, Granite Square, Dial Indicator, Arduino