Piano Key Dip Sensoring

• I wanted to measure the key dip of a piano key. I reasoned a hall sensor would be the easiest and cheapest way to accomplish this at the frequency we needed.
• I used a Si7210 hall sensor from Silicon Labs.
• I wrote an I2C driver for it in C++ with MBED.
• I quantified precision, accuracy, and sample time. For what we are doing we needed ~200us sample time (based on the speed of a piano key press), <+-0.25mm precision, and 5% accuracy.
• Used 2 point calibration curve for improving accuracy. Onboard FIR filter for improving precision.
• *photos are older (i.e. sample time is not 96000us)

Source Code

si7210

davidantaki ⋅ 3 years ago