A few weeks ago, I wrote a blog post how to connect a Espruino powered RAK8212 device with AWS IoT. In this posting, I would like to showcase how to connect a RAK8212 device to the Bosch IoT Suite Platform using the Quectel BG96’s built-in MQTT stack.
The example will be a simple data logger, periodically sending sensor values using NB-IoT connectivity.
You can find the source code and other material on the following github repository:
https://github.com/wklenk/rak8212-espruino-bosch-iot-platform
The RAK8212 has quite a few sensors on board:
- Temperature
- Humidity
- Barometeric Pressure
- Ambient Light
- Accelerometer
- Magnetometer
- Location (GNSS)
Assumptions
You are already familiar with the RAK 8212 and how to program it using Espruino.
Preparations
This example uses the Asset Communication package of the Bosch IoT Suite. There are quite a few things to configure before you can start, but there is an excellent tutorial that describes the steps in detail:
https://www.bosch-iot-suite.com/tutorials/connecting-a-simple-device-to-the-bosch-iot-suite/#book-and-configure
What you need to do (steps described in the tutorial):
- Create a Bosch IoT Suite account
- Subscribe to the Bosch IoT Suite Asset Communications package
- Configure a namespace for your things (digital twins)
- Create and configure a technical OAuth2.0 client
- Generate a test token to access the APIs of the Bosch IoT Suite
About Vorto Information Models
The IoT Suite gives you full freedom how to model the Digital Twin of your physical devices. However, there is an open source project named “Eclipse Vorto” (https://vorto.eclipse.org) that allows you to compose an Information Model of your device from several so-called Function Blocks. So, like with Lego Bricks, you can compose your device from other building blocks that can be shared by different devices.
Actually, to explain the full functionality behind that would go to far here …
The Information Model for the RAK8212 looks as follows:
vortolang 1.0
namespace org.klenk.connectivity.iot
version 1.0.0
displayname "RAK8212"
description "Information Model for RAK8212"
using com.bosch.iot.suite.example.octopussuiteedition.Humidity; 1.1.0
using org.eclipse.vorto.tutorial.Temperature; 1.0.0
using org.eclipse.vorto.Illuminance; 1.0.0
using com.bosch.iot.suite.example.octopussuiteedition.Magnetometer; 1.1.0
using org.eclipse.vorto.BarometricPressure; 1.0.0
using com.bosch.iot.suite.example.octopussuiteedition.Accelerometer; 1.1.0
using org.eclipse.vorto.Location; 1.0.0
infomodel RAK8212 {
functionblocks {
temperature as Temperature
barometricPressure as BarometricPressure
humidity as Humidity
magnetometer as Magnetometer
accelerometer as Accelerometer
illuminance as Illuminance
location as Location
}
}
One of the several advantages to model a device in an Information Model is that you now can generate code or other helpful things from it, like for instance the device provisioning script.
Again, this is out of scope for now, but the provisioning script generated from this Information Model is available in this repository (rak8212-device-provisioning-msg.json)
Have a look at this Youtube channel of Tim Grossmann for more inspiration about Eclipse Vorto. https://www.youtube.com/channel/UC9_Bk9247GgJ3k9O7yxctFg/featured
Device Provisioning
Again, the Bosch tutorial at https://www.bosch-iot-suite.com/tutorials/connecting-a-simple-device-to-the-bosch-iot-suite/#book-and-configure gives detailed instructions how to register your device with the Bosch IoT Suite.
But, as the RAK8212 has its own Information Model and provisioning script, use this one that is available in this repository:
rak8212-device-provisioning-msg.json
{
"id": "<your namespace>:rak8212",
"hub": {
"device": {
"enabled": true
},
"credentials": {
"type": "hashed-password",
"secrets": [
{
"password": "<your-device-password>"
}
]
}
},
"things": {
"thing": {
"attributes": {
"thingName": "RAK8212",
"definition": "org.klenk.connectivity.iot:RAK8212:1.0.0"
},
"features": {
"temperature": {
"definition": [
"org.eclipse.vorto.tutorial:Temperature:1.0.0"
],
"properties": {
"status": {
"value": 0.0,
"unit": ""
}
}
},
How to send telemetry data
To send telemetry data and in this way update the Digital Twin, you need to built up a Eclise Ditto message and publish it to topic telemetry.
sendAtCommandAndWaitForPrompt('AT+QMTPUB=0,1,1,0,'
+ JSON.stringify("telemetry"),
5000,
'{' +
' "topic": "org.klenk.connectivity.iot/rak8212/things/twin/commands/modify",' +
' "headers": {},' +
' "path": "/features/temperature/properties",' +
' "value": {' +
' "status": {' +
' "value": ' + currentTemperature + ',' +
' "unit": "Degree Celsius"' +
' }' +
' }' +
'}',
'+QMTPUB:'
)
.then( ... )
Using the Quectal BG96 module’s command AT+QMTPUB to publish a message to a MQTT topic, this code section updates the feature “temperature” of the Digital Twin.
How to subscribe to “modified” events of the Digital Twin
The built-in MQTT client of the Quectel BG96 makes it easy to subscribe to topics: You just need to use the AT+QMTSUB command to subscribe to topic command/+/+/req/#.
sendAtCommand('AT+QMTSUB=0,1,' + JSON.stringify("command/+/+/req/#") + ',1', 15000, '+QMTSUB:')
.then( ... )
Now, whenever a message is received on this topic, the MQTT client creates an output line starting with +QMTRECV: , like the following one:
] "\r\n+QMTRECV: 0,3,\"command///req/2240e49bdde-57ad-4652-b557-70f2dcf7"
] "41c0replies/modified\",\"{\"topic\":\"org.klenk.connectivity.iot"
] "/rak8212/things/twin/events/modified\",\"headers\":{\"sec-fetch-mode\":\"cors\",
....
You can see this output if you put the debug mode on. In case someone changed the device’s digital twin, we will receive a Eclise Ditto “modified” message like the following one:
{
"topic": "org.klenk.connectivity.iot/rak8212/things/twin/events/modified",
"headers": {
"sec-fetch-mode": "cors",
"referer": "https://apidocs.bosch-iot-suite.com/?urls.primaryName=Bosch%20IoT%20Things%20-%20API%20v2",
"sec-fetch-site": "same-site",
"accept-language": "de-DE, de;q=0.9, en-US;q=0.8, en;q=0.7",
"correlation-id": "0e49bdde-57ad-4652-b557-70f2dcf741c0",
"dnt": "1",
"source": "iot-suite:service:iot-things-eu-1:50058525-a6ed-4401-9984-f678cd509323_things/full-access",
"version": 2,
"accept": "application/json",
"host": "things.eu-1.bosch-iot-suite.com",
"content-type": "application/vnd.eclipse.ditto+json",
"accept-encoding": "gzip, deflate, br"
},
"path": "/features/temperature/properties",
"value": {
"status": {
"value": 21.61,
"unit": "Degree Celsius"
}
},
"revision": 525,
"timestamp": "2019-09-22T10:58:49.666Z"
}
This one says that the feature “temperature” was modified.
In order to process this message, you just have to write a “handler” that deals with this incoming message.
Conclusion
As the Quectel BG96 module already has built in a MQTT stack, it is simple to communicate with the Bosch IoT Suite using this protocol. Using Espruino, one can efficiently build IoT prototypes without a big learning curve in regards to the programming of embedded devices.
However, it needs to be evaluated if MQTT in combination with this kind of verbose Eclise Ditto messages is actually a viable way for NB-IoT communication, where every transmitted byte counts to save energy and communication costs.
espruino.com
2v06 (c) 2019 G.Williams
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>onInit();
=undefined
["sys get ver\r\n"
] "R"
] "N2483 1.0.5 Oct"
] " 31 2018 15:06:5"
] "2\r\n"
Version: RN2483 1.0.5 Oct 31 2018 15:06:52
["mac reset 868\r\n"
] "o"
] "k\r\n"
["mac set adr on\r\n"
] "o"
] "k\r\n"
["mac set appeui 70B3D57EXXXXXXXX\r\n"
] "o"
] "k\r\n"
["mac set deveui 00022CBFXXXXXXXX\r\n"
] "o"
] "k\r\n"
["mac set appkey 625C109CA95ADA37E9D0EA64XXXXXXXX\r\n"
] "o"
] "k\r\n"
["mac join otaa\r\n"
] "o"
] "k\r\n"
] "a"
] "ccepted\r\n"
Result: accepted
RN2483 go to sleep
["sys sleep 86400000\r\n"
RN2483 sent to sleep
Periodic task started.
RN2483 wake up
] "\u0000"
] "ok\r\n"
["\r\n"
] "inv"
] "alid_param\r\n"
wake up finished
["mac tx uncnf 1 42\r\n"
] "o"
] "k\r\n"
] "m"
] "ac_tx_ok\r\n"
RN2483 go to sleep
["sys sleep 86400000\r\n"
Periodic task done.
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