Gökhan Kurt
Published © GPL3+

Azure IoT Edge with Sense HAT and Raspberry Pi

An introduction to Azure IoT Edge using Sense HAT and Raspberry Pi.

IntermediateFull instructions provided4 hours4,453
Azure IoT Edge with Sense HAT and Raspberry Pi

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Code

main.py

Python
# Copyright (c) Microsoft. All rights reserved.
# Licensed under the MIT license. See LICENSE file in the project root for
# full license information.

import random
import time
import sys
import iothub_client
from sense_hat import SenseHat
import datetime
import json
# pylint: disable=E0611
from iothub_client import IoTHubModuleClient, IoTHubClientError, IoTHubTransportProvider
from iothub_client import IoTHubMessage, IoTHubMessageDispositionResult, IoTHubError

# messageTimeout - the maximum time in milliseconds until a message times out.
# The timeout period starts at IoTHubModuleClient.send_event_async.
# By default, messages do not expire.
MESSAGE_TIMEOUT = 10000

# global counters
RECEIVE_CALLBACKS = 0
SEND_CALLBACKS = 0
SEND_SENSEHAT_CALLBACKS = 0

# Choose HTTP, AMQP or MQTT as transport protocol.  Currently only MQTT is supported.
PROTOCOL = IoTHubTransportProvider.MQTT


# read sense hat and send
def read_and_send_measurements_from_sensehat(hubManager):
    global SEND_SENSEHAT_CALLBACKS
    sense = SenseHat()
    sense.clear()
    temperature = sense.get_temperature()
    temperature_h = sense.get_temperature_from_humidity()
    temperature_p = sense.get_temperature_from_pressure()
    humidity = sense.get_humidity()
    pressure = sense.get_pressure()
    timeCreated = datetime.datetime.utcnow().isoformat()
    MSG_TXT = "{\"temperature\": %.2f,\"temperature_h\": %.2f,\"temperature_p\": %.2f,\"humidity\": %.2f,\"pressure\": %.2f,\"timeCreated\": \"%s\"}"
    msg_txt_formatted = MSG_TXT % (temperature, temperature_h, temperature_p, humidity, pressure, timeCreated)
    message = IoTHubMessage(msg_txt_formatted)
    hubManager.forward_event_to_output("output2", message, 0)
    SEND_SENSEHAT_CALLBACKS += 1
    print ( "    Total sensehat messages sent: %d" % SEND_SENSEHAT_CALLBACKS )

# Callback received when the message that we're forwarding is processed.
def send_confirmation_callback(message, result, user_context):
    global SEND_CALLBACKS
    print ( "Confirmation[%d] received for message with result = %s" % (user_context, result) )
    map_properties = message.properties()
    key_value_pair = map_properties.get_internals()
    print ( "    Properties: %s" % key_value_pair )
    SEND_CALLBACKS += 1
    print ( "    Total calls confirmed: %d" % SEND_CALLBACKS )


# receive_message_callback is invoked when an incoming message arrives on the specified 
# input queue (in the case of this sample, "input1").  Because this is a filter module, 
# we will forward this message onto the "output1" queue.
def receive_message_callback(message, hubManager):
    global RECEIVE_CALLBACKS
    message_buffer = message.get_bytearray()
    size = len(message_buffer)
    print ( "    Data: <<<%s>>> & Size=%d" % (message_buffer[:size].decode('utf-8'), size) )
    map_properties = message.properties()
    key_value_pair = map_properties.get_internals()
    print ( "    Properties: %s" % key_value_pair )
    RECEIVE_CALLBACKS += 1
    print ( "    Total calls received: %d" % RECEIVE_CALLBACKS )
    hubManager.forward_event_to_output("output1", message, 0)
    return IoTHubMessageDispositionResult.ACCEPTED


class HubManager(object):

    def __init__(
            self,
            protocol=IoTHubTransportProvider.MQTT):
        self.client_protocol = protocol
        self.client = IoTHubModuleClient()
        self.client.create_from_environment(protocol)

        # set the time until a message times out
        self.client.set_option("messageTimeout", MESSAGE_TIMEOUT)
        
        # sets the callback when a message arrives on "input1" queue.  Messages sent to 
        # other inputs or to the default will be silently discarded.
        self.client.set_message_callback("input1", receive_message_callback, self)

    # Forwards the message received onto the next stage in the process.
    def forward_event_to_output(self, outputQueueName, event, send_context):
        self.client.send_event_async(
            outputQueueName, event, send_confirmation_callback, send_context)

def main(protocol):
    try:
        print ( "\nPython %s\n" % sys.version )
        print ( "IoT Hub Client for Python" )

        hub_manager = HubManager(protocol)

        print ( "Starting the IoT Hub Python sample using protocol %s..." % hub_manager.client_protocol )
        print ( "The sample is now waiting for messages and will indefinitely.  Press Ctrl-C to exit. ")

        while True:
            read_and_send_measurements_from_sensehat(hub_manager)
            time.sleep(1)

    except IoTHubError as iothub_error:
        print ( "Unexpected error %s from IoTHub" % iothub_error )
        return
    except KeyboardInterrupt:
        print ( "IoTHubModuleClient sample stopped" )

if __name__ == '__main__':
    main(PROTOCOL)

Dockerfile.arm32v7

Dockerfile
FROM resin/raspberrypi3-debian:stretch

WORKDIR /app

RUN apt-get update && \
    apt-get install -y --no-install-recommends libboost-python1.62.0 python3-pip libpython3-dev && \
    apt-get install sense-hat && \
    rm -rf /var/lib/apt/lists/* 

RUN pip3 install --upgrade pip 
RUN pip install --upgrade setuptools 
COPY requirements.txt ./
RUN pip install -r requirements.txt

COPY . .

#RUN useradd -ms /bin/bash moduleuser
#USER moduleuser

ENTRYPOINT [ "python3", "-u", "./main.py" ]

module.json

JSON
{
    "$schema-version": "0.0.1",
    "description": "",
    "image": {
        "repository": "sensehatContainerRegistry.azurecr.io/sensehatpythonmodule",
        "tag": {
            "version": "0.0.3",
            "platforms": {
                "amd64": "./Dockerfile.amd64",
                "amd64.debug": "./Dockerfile.amd64.debug",
                "arm32v7": "./Dockerfile.arm32v7"
            }
        },
        "buildOptions": []
    },
    "language": "python"
}

deployment.template.json

JSON
{
  "$schema-template": "1.0.0",
  "modulesContent": {
    "$edgeAgent": {
      "properties.desired": {
        "schemaVersion": "1.0",
        "runtime": {
          "type": "docker",
          "settings": {
            "minDockerVersion": "v1.25",
            "loggingOptions": "",
            "registryCredentials": {
              "sensehatcontainerregistry": {
                "username": "$CONTAINER_REGISTRY_USERNAME_sensehatcontainerregistry",
                "password": "$CONTAINER_REGISTRY_PASSWORD_sensehatcontainerregistry",
                "address": "sensehatcontainerregistry.azurecr.io"
              }
            }
          }
        },
        "systemModules": {
          "edgeAgent": {
            "type": "docker",
            "settings": {
              "image": "mcr.microsoft.com/azureiotedge-agent:1.0",
              "createOptions": {}
            }
          },
          "edgeHub": {
            "type": "docker",
            "status": "running",
            "restartPolicy": "always",
            "settings": {
              "image": "mcr.microsoft.com/azureiotedge-hub:1.0",
              "createOptions": {
                "HostConfig": {
                  "PortBindings": {
                    "5671/tcp": [
                      {
                        "HostPort": "5671"
                      }
                    ],
                    "8883/tcp": [
                      {
                        "HostPort": "8883"
                      }
                    ],
                    "443/tcp": [
                      {
                        "HostPort": "443"
                      }
                    ]
                  }
                }
              }
            }
          }
        },
        "modules": {
          "tempSensor": {
            "version": "1.0",
            "type": "docker",
            "status": "running",
            "restartPolicy": "always",
            "settings": {
              "image": "mcr.microsoft.com/azureiotedge-simulated-temperature-sensor:1.0",
              "createOptions": {}
            }
          },
          "SenseHatPythonModule": {
            "version": "1.0",
            "type": "docker",
            "status": "running",
            "restartPolicy": "always",
            "settings": {
              "image": "${MODULES.SenseHatPythonModule.arm32v7}",
              "createOptions": "{\"HostConfig\":{\"Privileged\": true}}"
            }
          }
        }
      }
    },
    "$edgeHub": {
      "properties.desired": {
        "schemaVersion": "1.0",
        "routes": {
          "SenseHatPythonModuleToIoTHub": "FROM /messages/modules/SenseHatPythonModule/outputs/* INTO $upstream",
          "sensorToSenseHatPythonModule": "FROM /messages/modules/tempSensor/outputs/temperatureOutput INTO BrokeredEndpoint(\"/modules/SenseHatPythonModule/inputs/input1\")"
        },
        "storeAndForwardConfiguration": {
          "timeToLiveSecs": 7200
        }
      }
    }
  }
}

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Gökhan Kurt

Gökhan Kurt

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