Hacking Digital Calipers for Automated Measurements and Sorta-Micron Accuracy
1 min read
Summary
Matthias Wandel is probably best known for making machine tools from wood, but he has also hacked cheap digital callipers to connect them to a Raspberry Pi for automated metrology experiments.
He discovered that the 24-bit output should provide results to within a micron, but the readings rapidly fluctuated between two levels, making it difficult to get an average reading quickly enough.
This did, however, provide a useful experiment in signal processing for those wanting to automate such tasks on a budget.
The callipers used a synchronous serial connection, which Wandel accessed through a hacked resistor ladder connected to the Pi at 1.8v.
After solving noise problems with capacitors and software debouncing, Wandel was able to gather data for assessment.
