LoRa is great when there’s a network available, but for in-person water quality readings I thought it’d be convenient to add Bluetooth.

I had a spare BLE Nano v2 sitting around, so decided to wire that in. It acts as a relay, broadcasting everything that the Water Quality sensor outputs over serial, and pushing it out via Bluetooth.

Because this is the same setup as my air quality sensor project, I could clone the Air Quality iOS app to become a Water Quality iOS app. The app saves all of the data to my iPhone/iPad’s Core Database, and there’s an export to CSV function too.

Quick graph of the first sensor data I measured.

Sample data: Google Spreadsheet / Raw CSV.

It’s pretty snug on the mini breadboard, and I cheated a bit by adding in the 3.3v BLE board on the wrong side of the power isolator to avoid having to drop down the 5v TX pin from the Arduino side to 3.3v, but it all still fits in the waterproof enclosure and functions very nicely.

The Bluetooth BLE board is the red one on the right.

Next step is to update my Rails site to be able to include water quality data, add some API authentication, and host it. Then all of the data the iOS apps are getting will be posted to a database and graphed nicely, both on a linear graph, and on a map.

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