AVNET's iotconnect.io cloud platform is an online service that you can use to send data to, and then show it on a dashboard. In this blog series I'm learning the Python SDK and integrating BLE devices. In this post, two topics: how is the image retrieved from the OnSemi Smart Shot camera, and how is the image sent to the cloud. image source: RSL10 Smart Shot Color Camera user's manual

Getting the Image from the Camera via BLE

When the cloud application needs an image off the remote camera, it sends a command to the IIOTConnect SmartEdge Gateway.

image: when the cloud user interface requests an image from the camera, it generates a command to the camera (child) via the device (gateway)

This triggers a Python function on the gateway.

def SmartShotCaptureCmd(msg):

This happens via a callback mechanism that listens for cloud commands:

# SDK call backs
def callbackMessageMyPythonSensorValue(msg):
    global sdk, my_command_dict, d2cMsg
    myprint(msg)
    return
    if msg != None and len(list(msg.items())) != 0:
        cmdType = msg["cmdType"]
        data = msg["data"]
        # For non OTA(commands etc)
        if cmdType != "0x02" and data != None:
            #
            # Put code here to do command
            #
            myprint("Message: " + str(msg))
            if (msg['data']['command'] == ' SmartShotCaptureCmd'):
                SmartShotCaptureCmd(data)
            elif # ...

After looking up the correct child in the list of all BLE devices in reach of the gateway, a connection is made.

        RSL10DataLock.acquire()
        smartshot = btle.Peripheral(data.upper())

An image is retrieved and written to the gateway's file system

            #Start capture
            myprint("Start Capture " + datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S.000Z"))
            imagefp = 0
            smartshot.setMTU(247)
            smartshot.writeCharacteristic(ChControlUuid, struct.pack('<b', 0x01))
            # Wait for capture complete notification
            smartshot.waitForNotifications(5)
            # Start image transfer
            PhotoFrameLength = 14
            smartshot.writeCharacteristic(ChControlUuid, struct.pack('<b', 0x04))
            smartshot.waitForNotifications(2)
            while (imagelength > 0) and ( count < 5000):
                count = count + 1
                imagelength = imagelength - PhotoFrameLength
                smartshot.waitForNotifications(1)

...

        if ( count < 5000):
            if (imagefp != 0):
                myprint("ImageClosed")
                imagefp.close()
            Index = 0
            NameIndex = 0
            count = 0
            for item in SmartShotIndex:
                if (item[0] == str(data)):
                    Index = item[1]
                    SmartShotIndex[count] = [data, Index + 1]
                count = count + 1    
            for item in AddressList:
                if (item['addr'] == str(data)):
                    NameIndex = item['name']
            photoname = str(uniqueId) + str(NameIndex) + "Capture" + str(Index) + ".jpg"
            myprint(photoname)
            os.system("mv capture.jpg " + photoname)
            SmartShotVersion = -1
            for item in AddressList:
                if item['addr'] == data:
                    SmartShotVersion = item['applicationversion']
                
            data1 = {
                'SmartShotIndex':Index,
                'SmartShotPhoto':photoname,
                'SmartShotVersion':SmartShotVersion,
                'SmartShotStatus':"Online"
            }
            if (type == 1):
                packet = {
                    "uniqueId": "ONSemi" + data.replace(':', '')[6:].upper() + "SmartShotBlackWhite"+ uniqueId[:6],
                    "time": datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S.000Z"),
                    "data": data1
                }
                OnBoard.SendDataNow(packet)
                result = SendPhotoToCloud(photoname,"ONSemi" + data.replace(':', '')[6:].upper() + "SmartShotBlackWhite"+ uniqueId[:6])
            else:
                packet = {
                    "uniqueId": "ONSemi" + data.replace(':', '')[6:].upper() + "SmartShotColor"+ uniqueId[:6],
                    "time": datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S.000Z"),
                    "data": data1
                }              
                OnBoard.SendDataNow(packet)
                result = SendPhotoToCloud(photoname,"ONSemi" + data.replace(':', '')[6:].upper() + "SmartShotColor"+ uniqueId[:6])
            myprint("PhotoSent " + datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S.000Z"))
            os.system('rm ' + photoname)
            result = 0

Sending the Captured Photo to the Cloud

One of the last lines of code in the previous section was the command to upload the image to the cloud:

result = SendPhotoToCloud(photoname,"ONSemi" + data.replace(':', '')[6:].upper() + "SmartShotColor"+ uniqueId[:6])

This function uses a custom web service on iotconnect.io to load that data.

http_photo_upload = https://onsemirslapi.iotconnect.io/api/device/addGatewayImage

When the image is sent, a number of attributes are added to the payload, like the gateway and child identifiers.

Then the image is loaded:

    files = {'image': (name, open(name, 'rb'))}

    response = requests.request("POST", url, data=payload, headers=headers, files=files)
    response = response.json()
    if ((response != None ) and (response['status'] == 200)):
        return 0
    else:
        return 1

image: gui after I requested an image

image: data arriving

image: the command sent from cloud to gateway

.