SmartGrowing

Serverless application monitoring plant growth affecting data using a Raspberry Pi and the Azure cloud.

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Preprequisites

• Raspberry pi, breadboard and dht11 sensor
• Python > 3.5
• Azure Account

Getting started I - Raspberry Pi

Follow these steps to setup a Raspberry Pi which reads DHT11 sensor data and sends them to an Azure Event Hub.

On your Raspberry Pi run the following commands:

1. Install Python and DHT11-Toolkit.

   sudo apt-get update
   
   sudo apt-get install build-essential python3-dev
   
   git clone https://github.com/coding-world/Python_DHT.git
   
   cd Python_DHT
   
   sudo python3 setup.py install
   
   

   
   

2. Install Azure Event Hub package for python.

   pip3 install azure-eventhub
   
   pip3 install azure-eventhub-checkpointstoreblob-aio
   

   
   

3. Add the following lines to your /home/pi/.profile (right click -> show hidden files, if bash is your login shell as per default on raspbian) to establish os variables containing your Event Hub auth information. Replace <your-connection-string> and <your-event-hub-name> with your Azure Event Hub connection string and name under SAS (Shared Access Signature) in your azure account.

   EVENT_HUB_CONN_STR=Endpoint='<your-connection-string>'
   
   export EVENT_HUB_CONN_STR
   
   EVENT_HUB_NAME='<your-event-hub-name>'
   
   export EVENT_HUB_NAME
   

   
   

4. Connect DHT11 sensor.

   Plugin DHT11 sensor into breadboard.
   
   Connect 4.7 Ω resistor (yellow, purple, black, brown, gold) to pin 1 and 2 on the DHT11.
   
   Connect 3.3 V power supply (pin 1 on Raspberry Pi 3) to pin 1 on DHT11.
   
   Connect gpio 4 on Raspberry Pi (pin 7) to DHT11 pin 2.
   
   Connect ground (pin 9 on Raspberry Pi 3) to DHT11 pin 4.
   
   

   
   

   The setup should look like this.

   
   

5. Create cron-job to execute smart_growing.py every minute.

   crontab -e
   
   Add * * * * * . $HOME/.profile; python3 /home/pi/<path-to-script>/smart_growing.py >> /home/pi/log.txt to end of file.
   
   Check out https://crontab.guru/ for examples on how to use cron.
   

Now you should be able to run the SmartGrowing/python_scripts/smart_growing.py script from this repository.

To set up an Event Hub continue to section II.

Getting started II - Azure

1. Create a free Azure account.

2. Create an Azure Event Hub according to https://docs.microsoft.com/de-de/azure/event-hubs/event-hubs-create .

3. Create an Azure AD according to https://docs.microsoft.com/de-de/azure/active-directory/develop/quickstart-create-new-tenant .

4. Create an Azure Cosmos DB according to https://docs.microsoft.com/de-de/azure/cosmos-db/create-cosmosdb-resources-portal .

5. Azure Function

   
   

   To run the Functions-App you will need Visual Studio Code and the following plugins for Azure.

   
   
   
   

   Open the the folder SmartGrowing/azure_functions in Visual Studio Code. To debug local edit the local.settings.json and add the following information. Of course replace <your-event-hub-connection-string> and <your-cosmos-db-connection-string> with the accurate information from your azure account.

   
   

   "AzureEventHubConnectionString": "<your-event-hub-connection-string>",
   
   "CosmosDBConnection": "<your-cosmos-db-connection-string>"
   

   To deploy the Functions-App to Azure you will need to add the same information in the config of your functions app (Azure portal) as seen in the following image.

   
   
   
   

   To deploy the function to Azure just hit the cloud icon.

   
   

Getting started III - Xamarin.Forms

Open the Visual Studio solution in the folder SmartGrowing/xamarin_app and replace the values in SmartGrowing/xamarin_app/xamarin_app/Helpers/Constants.cs with your Azure information.