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Published June 6, 2019

Greenhouse Monitoring with Discovery Kit IoT and Android

How to build a greenhouse monitoring system that measures environment parameters like temperature and humidity.

AdvancedFull instructions provided3,769

Greenhouse Monitoring with Discovery Kit IoT and Android

Things used in this project

Hardware components

STM32 B-L475E-IOT01A Discovery kit for IoT

Software apps and online services

Arm Mbed Studio

Amazon Web Services AWS IoT

Android Studio

Story

Introduction

The goal of this project is building a greenhouse monitoring system that measures parameters like temperature and humidity, and transmits data through a wireless connection to an android app. This app receives the data and displays it using a program interface, allowing us to remote monitor our greenhouse.

This is the model of the project:

Motivations

The main feature of greenhouse cultivation is to have different environmental conditions so that we can grow different types of plants, vegetables, etc. Of course depending on what we cultivate we must ensure that values such as temperature and humidity remain in the ideal range for that plant. In our case we take as an example the cultivation of tomatoes: in fact, for the cultivation of the tomato, the temperature should be between 20 and 26 ° C for optimal cultivation, moreover the ideal humidity for a correct conservation is between 80% and 90% during the day, 65-75% during the night.

Step 1: Thing, Certificate and Policy in AWS

To start our project we have to create a "thing" on AWS IoT to allow the connection between the cloud and the stm board. In the IoT core screen just go to "Manage" -> "Things" -> "Create" -> "Create a single thing".

Once the "thing" is created, the object certificate, the public key and the private key will be generated automatically by clicking "One-click certificate creation". Download everything as we will need it later, and hit Activate.

After that we have to create a policy of the thing in order to allow the exchange of messages. Go to "Secure" -> "Policies" -> "Create". Then, click advanced mode and attach the policy document to the thing and modify it as shown below.

Policy

Step 2: Programming the board

The program is created using the online compiler of ARM, using MBED.

You can open a free account on mbed.com and write the code in the compiler there.

After we are done creating the IoT thing in AWS IoT, we have to program the board. The board will connect with AWS IoT by using WiFi and MQTT protocol and publish the measured values in a topic.

First, we have to initialize sensor values and connect to Wi-Fi. In the "mbed_app.json" section we have to insert the correct Wi-Fi SSID and the Wi-Fi password in order to establish the connection.

Second, we have to insert the certificate and the private key previously downloaded in the "MQTT_server_setting.h" section.

Then we get the sensor data and through MQTT protocol we publish them to the topic.

After finishing with the code on the compiler, click "Compile". A file will be generated. Take this file and insert it into the folder of the board. Open Realterm if you want to see the messages and the values being sent.

The full code for the program is available on GitHub.

Step 3: Creating rules in AWS IoT

Finally we can manage our data. Create a rule and add action like storing updated data in a S3 bucket or DynamoDb. To do this, we need to go to "Act" -> "Create". So we have to write an SQL query to choose which data we want to use for our actions. Finally, in the same section, we can add action to manage our data, like store them in a S3 bucket, etc.

Creating a rule

Step 4: Android Application

To read the data remotely, so we can monitor the environment from our smartphone we wrote a simple android app that shows the data in real time, and sends you notifications if the values are too high or too low.

Clicking the Connect button, will establish a connection to the AWS IoT platform The Android App subscribes on the MQTT topic and receives the values that were published by the IoT board.

1 / 3

For this to make it work, we have to modify our thing that we created earlier for the board.

MQTT enables the IoT device to send, and publish information in a given topic. The publisher publishes the values in the topic, and the sender subscribes to the channel in order to get the values. The Board is the publisher and the mobile device is the subscriber.

You can start by reading the AWS-sdk android samples provided by AWS on this GitHub page.

Then edit the GUI, to add some textViews for the values and the buttons needed for Connection, Disconnect, and Submit.

Make sure to add all the dependencies on the "build.gradle" file.

The whole code together with all the events and buttons, connection and subscription methods that we added or modified is available on GitHub.

Links

Github: https://github.com/shend5?tab=repositories

LinkedIn accounts:

Matteo Rizza: https://www.linkedin.com/in/matteo-rizza/
Shend Osmanaj: https://www.linkedin.com/in/shendosmanaj/
Shilpa Joy: https://www.linkedin.com/in/shilpa-joy/
Alfin Joji: https://www.linkedin.com/in/alfin-joji-947b44111/

Slide presentation:

Idea presentation: https://www.slideshare.net/ShilpaJoy5/greenhouse-weather-monitoring
Project overview presentation: https://www.slideshare.net/ShilpaJoy5/greenhouse-monitoring
Final Project Presentation: https://www.slideshare.net/MatteoRizza/greenhouse-monitoring-final

#include "mbed.h"
#include "mbed-trace/mbed_trace.h"
#include "mbedtls/debug.h"

#include "stm32l475e_iot01_tsensor.h"
#include "stm32l475e_iot01_hsensor.h"

#include "core/cloud.h"

#define AWS_IOT_UPDATE_FREQUENCY    10

DigitalOut led(LED1);

// Connect services 
int connect(){
    int result = 0;

    int cloud_status = cloud_connect();
    if(cloud_status == 1){
        result = 1;    
    }
    
    return result;
}

// Main
int main(){
    mbed_trace_init();
    
    printf("IoT device starting\r\n");
    
    // Define sensor vars 
    float temperature = 0;
    float humidity = 0;
    
    // Initalize sensors 
    BSP_TSENSOR_Init();
    BSP_HSENSOR_Init();
    
    // Initialize cloud (connect wifi) 
    cloud_init();
    
    // Connect to network 
    int connected = connect();
    while(1) {
        if(connected == 1){
            //It works
            led = 1;
            
            // Get current sensor data
            temperature = BSP_TSENSOR_ReadTemp();
            humidity = BSP_HSENSOR_ReadHumidity();
            
            // Send message to cloud
            cloud_send(temperature,humidity);
            
            // wait 
            wait(AWS_IOT_UPDATE_FREQUENCY);
        }else{
            // It doens't work  
            wait(2);  
            led=0;
        }
    }
}

#ifndef __MQTT_SERVER_SETTING_H__
#define __MQTT_SERVER_SETTING_H__

const char MQTT_SERVER_HOST_NAME[] = "a2ljeoyca4z5yq-ats.iot.eu-central-1.amazonaws.com";
const char MQTT_CLIENT_ID[] = "STM32L475VGIOT01A";
const char MQTT_USERNAME[] = "STM32L4";
const char MQTT_PASSWORD[] = "";
const char MQTT_TOPIC_PUB[] = "pubtopic";
const char MQTT_TOPIC_SUB[] = "subtopic";


const int MQTT_SERVER_PORT = 8883;

/*
 * Root CA certificate here in PEM format.
 * "-----BEGIN CERTIFICATE-----\n"
 * ...
 * "-----END CERTIFICATE-----\n";
 */
/* Amazon Legacy Root CA */
/*const char* SSL_CA_PEM = "-----BEGIN CERTIFICATE-----\n"
"MIIE0zCCA7ugAwIBAgIQGNrRniZ96LtKIVjNzGs7SjANBgkqhkiG9w0BAQUFADCB\n"
"yjELMAkGA1UEBhMCVVMxFzAVBgNVBAoTDlZlcmlTaWduLCBJbmMuMR8wHQYDVQQL\n"
"ExZWZXJpU2lnbiBUcnVzdCBOZXR3b3JrMTowOAYDVQQLEzEoYykgMjAwNiBWZXJp\n"
"U2lnbiwgSW5jLiAtIEZvciBhdXRob3JpemVkIHVzZSBvbmx5MUUwQwYDVQQDEzxW\n"
"ZXJpU2lnbiBDbGFzcyAzIFB1YmxpYyBQcmltYXJ5IENlcnRpZmljYXRpb24gQXV0\n"
"aG9yaXR5IC0gRzUwHhcNMDYxMTA4MDAwMDAwWhcNMzYwNzE2MjM1OTU5WjCByjEL\n"
"MAkGA1UEBhMCVVMxFzAVBgNVBAoTDlZlcmlTaWduLCBJbmMuMR8wHQYDVQQLExZW\n"
"ZXJpU2lnbiBUcnVzdCBOZXR3b3JrMTowOAYDVQQLEzEoYykgMjAwNiBWZXJpU2ln\n"
"biwgSW5jLiAtIEZvciBhdXRob3JpemVkIHVzZSBvbmx5MUUwQwYDVQQDEzxWZXJp\n"
"U2lnbiBDbGFzcyAzIFB1YmxpYyBQcmltYXJ5IENlcnRpZmljYXRpb24gQXV0aG9y\n"
"aXR5IC0gRzUwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCvJAgIKXo1\n"
"nmAMqudLO07cfLw8RRy7K+D+KQL5VwijZIUVJ/XxrcgxiV0i6CqqpkKzj/i5Vbex\n"
"t0uz/o9+B1fs70PbZmIVYc9gDaTY3vjgw2IIPVQT60nKWVSFJuUrjxuf6/WhkcIz\n"
"SdhDY2pSS9KP6HBRTdGJaXvHcPaz3BJ023tdS1bTlr8Vd6Gw9KIl8q8ckmcY5fQG\n"
"BO+QueQA5N06tRn/Arr0PO7gi+s3i+z016zy9vA9r911kTMZHRxAy3QkGSGT2RT+\n"
"rCpSx4/VBEnkjWNHiDxpg8v+R70rfk/Fla4OndTRQ8Bnc+MUCH7lP59zuDMKz10/\n"
"NIeWiu5T6CUVAgMBAAGjgbIwga8wDwYDVR0TAQH/BAUwAwEB/zAOBgNVHQ8BAf8E\n"
"BAMCAQYwbQYIKwYBBQUHAQwEYTBfoV2gWzBZMFcwVRYJaW1hZ2UvZ2lmMCEwHzAH\n"
"BgUrDgMCGgQUj+XTGoasjY5rw8+AatRIGCx7GS4wJRYjaHR0cDovL2xvZ28udmVy\n"
"aXNpZ24uY29tL3ZzbG9nby5naWYwHQYDVR0OBBYEFH/TZafC3ey78DAJ80M5+gKv\n"
"MzEzMA0GCSqGSIb3DQEBBQUAA4IBAQCTJEowX2LP2BqYLz3q3JktvXf2pXkiOOzE\n"
"p6B4Eq1iDkVwZMXnl2YtmAl+X6/WzChl8gGqCBpH3vn5fJJaCGkgDdk+bW48DW7Y\n"
"5gaRQBi5+MHt39tBquCWIMnNZBU4gcmU7qKEKQsTb47bDN0lAtukixlE0kF6BWlK\n"
"WE9gyn6CagsCqiUXObXbf+eEZSqVir2G3l6BFoMtEMze/aiCKm0oHw0LxOXnGiYZ\n"
"4fQRbxC1lfznQgUy286dUV4otp6F01vvpX1FQHKOtw5rDgb7MzVIcbidJ4vEZV8N\n"
"hnacRHr2lVz2XTIIM6RUthg/aFzyQkqFOFSDX9HoLPKsEdao7WNq\n"
"-----END CERTIFICATE-----\n";*/

/* AmazonRootCA1.pem */
const char* SSL_CA_PEM = "-----BEGIN CERTIFICATE-----\n"
-
-
-
"-----END CERTIFICATE-----\n";

/*
 * (optional) Client certificate here in PEM format.
 * Set NULL if you don't use.
 * "-----BEGIN CERTIFICATE-----\n"
 * ...
 * "-----END CERTIFICATE-----\n";
 */
const char* SSL_CLIENT_CERT_PEM = "-----BEGIN CERTIFICATE-----\n"
-
-
-
"-----END CERTIFICATE-----\n";


/*
 * (optional) Client private key here in PEM format.
 * Set NULL if you don't use.
 * "-----BEGIN RSA PRIVATE KEY-----\n"
 * ...
 * "-----END RSA PRIVATE KEY-----\n";
 */
const char* SSL_CLIENT_PRIVATE_KEY_PEM = "-----BEGIN RSA PRIVATE KEY-----\n"
-
-
-
"-----END RSA PRIVATE KEY-----\n";

#endif /* __MQTT_SERVER_SETTING_H__ */

{
    "macros": [
        "MBEDTLS_USER_CONFIG_FILE=\"mbedtls_entropy_config.h\""
    ],
    "config": {
        "wifi-shield": {
            "help": "Options are internal, WIFI_ESP8266, WIFI_IDW0XX1",
            "value": "internal"
        },
        "wifi-ssid": {
            "help": "WiFi SSID",
            "value": "\"FASTWEB-B9614B\""
        },
        "wifi-password": {
            "help": "WiFi Password",
            "value": "\"example123\""
        },
        "wifi-tx": {
            "help": "TX pin for serial connection to external device",
            "value": "D1"
        },
        "wifi-rx": {
            "help": "RX pin for serial connection to external device",
            "value": "D0"
        },
        "wifi-spi_miso": {
            "help": "SPI-MISO connection to external device",
            "value": "PC_11"
        },
        "wifi-spi_mosi": {
            "help": "SPI-MOSI connection to external device",
            "value": "PC_12"
        },
        "wifi-spi_sclk": {
            "help": "SPI-CLOCK connection to external device",
            "value": "PC_10"
        },
        "wifi-spi_nss": {
            "help": "SPI chip select of external device",
            "value": "PE_0"
        },
        "wifi-reset": {
            "help": "WIFI module reset pin",
            "value": "PE_8"
        },
        "wifi-dataready": {
            "help": "WIFI module data ready pin",
            "value": "PE_1"
        },
        "wifi-wakeup": {
            "help": "WIFI module wakeup pin",
            "value": "PB_12"
        },
        "main-stack-size": {
            "value": 7000
        }
    },
    "target_overrides": {
        "*": {
            "target.network-default-interface-type": "ETHERNET",
            "nsapi.default-wifi-security": "WPA_WPA2",
            "nsapi.default-wifi-ssid": "\"\"",
            "nsapi.default-wifi-password": "\"\"",
            "mbed-trace.enable": true,
            "tls-socket.debug-level": 0,
            "platform.stdio-baud-rate": 115200,
            "platform.stdio-convert-newlines": false
        }
    }
}

#define MQTTCLIENT_QOS1 0
#define MQTTCLIENT_QOS2 0

#include "mbed.h"
#include "ISM43362Interface.h"
#include "NTPClient.h"
#include "MQTTNetwork.h"
#include "MQTTmbed.h"
#include "MQTT_server_setting.h"
#include "MQTTClient.h"
#include "mbed-trace/mbed_trace.h"
#include "mbed_events.h"
#include "mbedtls/error.h"

/*
    Private classes for MQTT handling
*/

ISM43362Interface wifi(false);

MQTTNetwork* mqttNetwork = NULL;
MQTT::Client<MQTTNetwork, Countdown>* mqttClient = NULL;

static unsigned short mqtt_message_id = 0;

/*
    Sync clock with NTP server
*/
void cloud_sync_clock(NetworkInterface* network){
    NTPClient ntp(network);
    
    /* use PTB server in Braunschweig */
    ntp.set_server("ptbtime1.ptb.de", 123);
    
    time_t now = ntp.get_timestamp();
    set_time(now);    
}

/*
    initialise cloud enviroment
*/
void cloud_init(){
    /* connect to the wifi network */
    int w_ret = wifi.connect(MBED_CONF_APP_WIFI_SSID, MBED_CONF_APP_WIFI_PASSWORD, NSAPI_SECURITY_WPA_WPA2);
    if(w_ret == 0) {
        printf("WIFI is now connected\r\n");
    }else{
        printf("Failed to connect WIFI\r\n");
    }
    
    /* sync the clock */
    cloud_sync_clock(&wifi);    
}

/*
    Sends an MQTT message to the cloud
*/
void cloud_send(float temperature, float humidity){
    MQTT::Message message;
    message.retained = false;
    message.dup = false;
    
    const size_t buf_size = 512;
    char *buf = new char[buf_size];
    message.payload = (void*)buf;
    
    message.qos = MQTT::QOS0;
    message.id = mqtt_message_id++;
    int ret = snprintf(buf, buf_size, 
                "{\"sensor\":{\"temperature\":%.2f,\"humidity\":%.2f}}", 
                temperature, humidity);
    if(ret < 0) {
        printf("ERROR: snprintf() returns %d.", ret);
    }
    message.payloadlen = ret;
    
    int rc = mqttClient->publish("stm32/sensor", message);
    if(rc != MQTT::SUCCESS) {
        printf("ERROR: rc from MQTT publish is %d\r\n", rc);
    }
    printf("Message published: %s\r\n",buf);
    delete[] buf; 
}

/*
    Connects to cloud using TLS socket
*/
int cloud_connect(){
    int result = 0;
      
    /* create mqtt network instance */
    printf("Initialising MQTT network...");
    mqttNetwork = new MQTTNetwork(&wifi);
    int rc = mqttNetwork->connect(MQTT_SERVER_HOST_NAME, MQTT_SERVER_PORT, SSL_CA_PEM,
                SSL_CLIENT_CERT_PEM, SSL_CLIENT_PRIVATE_KEY_PEM);
    if (rc != MQTT::SUCCESS){
        printf("MQTT network not successful\r\n");
        return 0;
    }      
    
    /* create mqtt data packet */
    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
    data.MQTTVersion = 3;
    data.clientID.cstring = (char *)MQTT_CLIENT_ID;
    data.username.cstring = (char *)MQTT_USERNAME;
    data.password.cstring = (char *)MQTT_PASSWORD;

    /* execute client and send data */
    mqttClient = new MQTT::Client<MQTTNetwork, Countdown>(*mqttNetwork);
    rc = mqttClient->connect(data);
    if (rc != MQTT::SUCCESS) {
        printf("MQTT client failed\r\n");
        return 0;
    }else{
        printf("MQTT connect successful\r\n");
        result = 1;
    }
    
    return result;
}

Greenhouse Monitoring with Discovery Kit IoT and Android

Things used in this project

Hardware components

Software apps and online services

Story

Introduction

Motivations

Step 1: Thing, Certificate and Policy in AWS

Step 2: Programming the board

Step 3: Creating rules in AWS IoT

Step 4: Android Application

Links

Code

main.cpp

MQTT_server_setting.h

mbed_app.json

cloud.cpp

Credits

Matteo Rizza

Shend Osmanaj

Shilpajoy 93

alfin joji

Comments

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Greenhouse Monitoring with Discovery Kit IoT and Android

Greenhouse Monitoring with Discovery Kit IoT and Android

Things used in this project

Hardware components

Software apps and online services

Story

Introduction

Motivations

Step 1: Thing, Certificate and Policy in AWS

Step 2: Programming the board

Step 3: Creating rules in AWS IoT

Step 4: Android Application

Links

Code

main.cpp

MQTT_server_setting.h

mbed_app.json

cloud.cpp

Credits

Matteo Rizza

Shend Osmanaj

Shilpajoy 93

alfin joji

Comments

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