ArduinoShield

Pressure Sensor Calibration for Homemade Densimeter

The sensor outputs an analog voltage that varies with applied force. This voltage is converted into a digital value using analogRead() (range: 0–1023).

A linear calibration equation is used to convert this reading into mass

Calibration Data

The following hardcoded values are used:

• zeroMass = 49.8
• zeroReading = 778
• knownMass = 110.6
• knownReading = 259

Output

The program continuously:

1. Reads the analog sensor value
2. Converts it to mass using the calibration equation
3. Prints both raw reading and calculated mass to the serial monitor

Raw reading: 512
Mass: 85.3 g

Known Bugs / Limitations

Different resistor values are being tested in the voltage divider to improve sensitivity and accuracy. Results may vary depending on the resistor.

2. Non-Linear Sensor Behavior

FSRs are inherently non-linear. This implementation assumes a linear relationship, which may introduce error, especially outside the calibrated range.

Hardware Notes

• Sensor: Force-Sensitive Resistor (FSR)
• Input Pin: A0
• Microcontroller: Arduino-compatible board
• Circuit: Voltage divider (FSR + resistor)

Future Work

• Implement non-linear calibration (e.g., exponential/log fit)
• Integrate mass readings into full density calculation pipeline
• Add real-time calibration interface via serial input
• Improve repeatability and measurement stability

Alpha Build Documentation

• Alpha Build - https://docs.google.com/document/d/1_ZNRy5aV_9XcpFfJprM5AeEUtTBAZkFf1owPfBoO9iQ/edit?usp=sharing
• Alpha Test Plan - https://docs.google.com/document/d/1SXkQXstxGwYJmzBSkHG-z-8G0-C6oroAPGTkn4TiCtQ/edit?usp=sharing

Beta Build Documentation

• Beta Build - https://docs.google.com/document/d/1fs_zSv_gkhbn85_mFjjC6zrKmSh5nXOdgN2fiGV2G-g/edit?usp=sharing
• Beta Test Plan - https://docs.google.com/document/d/1E2wE4QuUsBIM2U0-oblOg121ZjWiWZ_3sDpITYq9rYI/edit?tab=t.0

Beta Presentation

• Slide Deck - https://docs.google.com/presentation/d/1BMJHcqOLjPH9VT9NJFxybecDhRv366sLr2RfTS_22i4/edit?usp=sharing

Release Candidate Documenation

• Release Candidate - https://docs.google.com/document/d/1QZRxaM0PU--QsGB8tHn2rrG-0xElWLTbt4H6Ct_5NIU/edit?usp=sharing
• Preliminary Report - https://docs.google.com/document/d/1rlRpKkgs4_Q8DmHznruekNW2ZyRQ_ktouU92uwmhSHU/edit?usp=sharing