About the Project

This lab project involved building a digital scale using a Wheatstone bridge with strain gauges, an INA126PA op-amp, and an Arduino Nano. The scale, equipped with an OLED display (128x64 I2C), provided hands-on experience in circuit design, PCB soldering, and calibration for accurate weight measurements.

Project Background

The objective of this lab session was to design and build a digital scale capable of accurately measuring weight using strain gauge technology. The Wheatstone bridge was employed to detect minute changes in resistance caused by strain on the gauges, which were then amplified by the INA126PA op-amp. The amplified signal was processed by an Arduino Nano, which drove the OLED display to present the measured weight.

PCB Soldering and Component Integration

I began the project by soldering the PCB and carefully populating it with the required components, including the strain gauges, op-amp, and Arduino Nano. Ensuring precise soldering was critical to the project’s success, as it directly impacted the circuit’s functionality and the accuracy of the measurements.

Calibration Process

After assembling the circuit, I powered it up and began the calibration process. This involved applying known weights and adjusting the system until a linear calibration curve was achieved. Multiple rounds of calibration were necessary to fine-tune the system and ensure that it provided accurate and reliable measurements.

Weight Measurement Testing

Following calibration, I conducted a series of weight measurements using coins and washers to test the scale’s accuracy. The consistent results validated the effectiveness of the calibration and the overall design, demonstrating the practical application of the electronic principles learned during the lab sessions.

Key Learnings and Outcomes

This project deepened my understanding of electronic circuit design, sensor integration, and the importance of accurate calibration in measurement systems. It reinforced key concepts in electronics and provided a solid foundation for future work in embedded systems and sensor technologies.