AnotherSoilSensor

Soil Moisture Logger using NodeMCU, Capacitive Soil Mosutre Sensor v1.2, sending data either using MQTT, or pulling directly from device's REST API

Components

Capacitive Soil Moisture Sensor v1.2	NodeMCU 1.0 (ESP-12 Module)
Buy Capacitive Soil Moisture Sensor v1.2 on Amazon (CA)	Buy NodeMCU 12E on Amazon (CA)

Wiring

Quick Start

1. Download and install Arduino IDE

2. Go to File -> Preferences and under Additional Boards Manager URLs enter http://arduino.esp8266.com/stable/package_esp8266com_index.json

3. Install the necessary libraries by going to Tools -> Manage Libraries... and filtering on the libraries below.

ArduinoJson Version 6.18.0
ArduinoMQTTClient Version 0.1.5

4. Navigate to Tools -> Boards -> ESP8266 Boards and select NodeMCU 1.0 (ESP-12 Module).

5. Plug your board into your computer and select the appropriate Port in Tools -> Port, for example mine was /dev/ttyUSB0.

6. You can either Verify the sketch, to see if everything compiles without error, or you can Upload the sketch, which will compile it anyway and warn you of any issues then.

7. (Debugging) Open the Serial Monitor to 115200, and you should be able to tell if your device connects to Wifi, and if so, what its IP address is.

Usage

Configuration

AnotherSoilSensor is designed to be easy to setup and use. Without any prior configuration, you should be able to flash a device and use immediately.

NOTE By default, AnotherSoilSensor does not display verbose output to the Serial Monitor for security purposes. If you wish to see verbose output of the device, you must got into constants.h and change DEBUG to true.

NOTE The data produced for consumption by either the REST API or the MQTT Broker is represented as a percentage, from 0% - 100%. These values used for determining the mositure percentage are stored in constants.h as VALUE_AIR and VALUE_WATER, where VALUE_AIR is the value read from the sensor when it is exposed to air, and VALUE_WATER is the value read from the sensor when it is almost completely submerged.

These values were determined through experimentation with an example project in the Arduino IDE library. If the set values are not representative of your device, run an Analog Input example on your device and observe the output to acquire the corresponding values.

Once flashed, using a computer with Postman, open up your WiFi settings and find the network AnotherSoilSensor which you can login to using the password password.

Once connected to the network AnotherSoilSensor, in Postman, configure the below JSON body and send:

POST http://192.168.4.1/api/config/

Raw JSON Body
{
    "ssid": "", //WiFi SSID to connect to
    "pass": "", //WiFi Password for connection
    "mqttBroker": "", //The IP address or hostname for an MQTT broker
    "mqttPort": 1883, //The port number of the MQTT broker
    "mqttUpdateInterval": 5000, //The interval in which you would like the device to publish data to the MQTT broker, in milliseconds, minimum is 500 or 0.5 seconds
    "mqttUser":"", //A username for a valid MQTT user
    "mqttPass":"", //The password for the valid MQTT user
    "restUser":"", //The username you wish to use going forward to make authenticated requests to the device
    "restPass":"", //The password you wish to use going forward to make authenticated requests to the device
    "service": 1 //1 for REST, 2 for MQTT
}

Also valid ways to configure:

POST http://192.168.4.1/api/config/

// REST Configuration
Raw JSON Body
{
    "ssid": ""
    "pass": ""
    "restUser":"",
    "restPass":"",
    "service": 1
}

POST http://192.168.4.1/api/config/

// MQTT Configuration
Raw JSON Body
{
    "ssid": "",
    "pass": "",
    "mqttBroker": "",
    "mqttPort": 1883,
    "mqttUpdateInterval": 5000,
    "mqttUser":"",
    "mqttPass":"",
    "service": 2
}

If your device received and processed your configuration, you should receive a response like this:

// Device Response
{
    "success": true,
    "identifier": "##:##:##:##:##:##"
}

Otherwise, you will receive one of a possible few messages, indicating what corrections should be made.

The device will automatically reboot and attempt to connect to WiFi using the ssid and pass you provided. If it is unable to connect for whatever reason, it will revert to the configure stage again and you will be able to again attempt to configure the endpoint.

Reset Device

To clear any previous configuration and restore the default one, press the Flash button on your device.

REST API

You should be able to query the API by opening an API application such as Postman, setting Authentication to Basic Auth, setting Username and Password to what you set restUser and restPass to, and setting the URL to one of the possible endpoints, i.e. http://[device_ip]/api/read/moisture/, and getting a result back, i.e.

{
    "moisture": 80,
    "identifier": "##:##:##:##:##:##"
}

Documentation

GET http://[device_ip]/api/read/moisture/

{
"moisture": 80,
"identifier": "##:##:##:##:##:##"
}

GET http://[device_ip]/api/info/

{
"identifier": "##:##:##:##:##:##",
"version": "#.#.#"
}

WARNING The current REST API server setup is not a very secure method of protecting your endpoints, as the username and password are simply base64 encoded and can be read VERY easily as the server is not HTTPS encrypted. This is HOPEFULLY a temporary measure until something sturdier is put in place.

MQTT

Using an MQTT application such as MQTT Explorer, you should be able to see moisture as root topics, with the device's identifier as a sub-topic, i.e. moisture/##:##:##:##:##:##: 80