Measuring water quality using a conductivity sensor and a The Things Uno.
See also:
I’ve drawn up a Fritzing wiring diagram, but didn’t have the power isolator layout… I’ll update that soon.
| Atlas sensor pin | Power isolator pin | BLE Nano |
|---|---|---|
| VCC | 3.9V | VIN |
| GND | GND | GND |
| TX | A (In) | RX |
| RX | B (In) | - |
| Power isolator pin | Arduino The Things Uno (Leonardo) pin |
|---|---|
| VCC | 5V |
| GND | GND |
| A (Out) | 10 (Digital) |
| B (Out) | 11 (Digital) |
The Things Uno has a LoRaWAN chip that can send signals ~15km to The Things Network, which is great for remote sensors.
I'm using a secrets.h file to store the API keys. So to run this code on your Arduino, create a secrets file with the following code:
// secrets.h
#define APPEUI "YOUR_APP_EUI"
#define APPKEY "YOUR_APP_KEY"To get an APPEUI and APPKEY, follow The Things Network setup guide: https://www.thethingsnetwork.org/docs/devices/uno/quick-start.html#create-an-account
Once running, you should see this debug output to your serial monitor, where:
- EC = conductivity
- TDS = total dissolved solids
- SAL = salinity
- GRAV = specific gravity (sea water only)
-- STATUS
EUI: <EUI>
Battery: 3253
AppEUI: <APP_EUI>
DevEUI: <DEV_EUI>
Data Rate: 3
RX Delay 1: 1000
RX Delay 2: 2000
-- SENSOR READING
EC:0.00
TDS:0
SAL:0.00
GRAV:1.000
-- BYTE ARRAY TO SEND
30 2E 30 30 2C 30 2C 30 2E 30 30 2C 31 2E 30 30 30 00
Sending: mac tx uncnf 1 302E30302C302C302E30302C312E30303000Here are some sample readings from Port Willunga, South Australia, 2nd Jan 2019.
// Fresh water from the tap
EC:601.2
TDS:325
SAL:0.29
GRAV:1.000
// Beach water
EC:51631
TDS:27881
SAL:33.94
GRAV:1.026And one from the Adelaide CBD, South Australia, 2nd Jan 2019.
// Fresh water from the tap at a new apartment block
EC:600.4
TDS:324
SAL:0.29
GRAV:1.000
// Neverfail spring water
EC:211.6
TDS:114
SAL:0.10
GRAV:1.000I've been blogging about my experience setting these sensors up over at: sighmon.com/says
The story begins here: sighmon.com/says/water-quality-monitor/
The MIT License
Copyright (c) 2019 Simon Loffler
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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