OpenTholoMetri

OpenTholoMetri is heavily inspired by the OpenOBS-328 project by Ted Langhorst. Many thanks to Olpas for their support in making this project a reality and to Thomas More Digital Innovation for introducing me to this opportunity.

System Overview

The OpenTholoMetri is a data logging system designed for turbidity measurement using optical sensors. The system operates in a low-power mode, periodically waking up to take sensor readings, logging the data to an SD card with timestamps, and then returning to sleep.

Why does this project exist?

While the OpenOBS-328 is great, I found the documentation quite difficult to read. The fact of having to order PCBs (with minimum order quantities) made it hard to justify as a one-off sensor, which makes the accessibility of the sensor lower. That's why: to make water quality measurements accessible to anyone, even if they only want to build a couple. If you need to build these in bulk, I'd strongly recommend looking at the OpenOBS-328 instead.

Getting started

• View the materials list here
• View the build instructions here
• View the code documentation here

Features

• Low Power Operation: Efficient power management for extended battery life
• Accurate Sensing: Optical turbidity measurement with proximity and ambient light sensors
• Data Logging: Timestamps and sensor readings stored on SD card
• CSV Export: Easy-to-analyze data format

Tools

This project includes tools to help you work with the OpenTholoMetri:

• CSV Viewer: A browser-based basic tool to visualize your sensor data

Data Format

The device generates CSV files with the following format:

• Headers: Timestamp,Proximity,Ambient Light,Battery Voltage,Temperature (C),Turbidity Raw,Turbidity Voltage
• Timestamp format: YYYY-MM-DD HH:MM:SS
• All measurements are logged at regular intervals