NB-IoT and MQTT-SN

Hello,

to use the NB-IoT Shield with the Cloud of Things of Detusche telekom (based on Cumlocity) I have to use MQTT-SN.

Is there already a library for MQTT-SN and the NB-IoT shield available (from Sodaq or elsewhere) ?

Otherwise I would make a merge of the NB-IoT libraries of Sodaq with boriz/MQTT-SN-Arduino
lib.

Regards
Holger

2 Likes

Hi hlesch, I am situated in Germany right now as well, and one part of my project is to use the new NB-IoT network as the communication protocoll to connect into the cloud (the internet that is)

Since you’re more experienced than me at this point, I would like to trade thoughts with you regarding this and would like to ask a few questions.

You have probably purchased the NB-IoT & Cloud of Things package from Deutsche Telekom. But it’s quite costly. And the 300 euro price tag doesn’t seem to make sense, especially with what you’re getting.

1.) What exactly is the Cloud of Things offering? All I get from their site and youtube video, is that their plan is to make whatever object in your house to be wifi connected, having their own software backend for you to monitor (through their site most likely) Are they practically like the Artik Cloud platform by Samsung that is offering Platform as a Service? (I think that’s what I understand…)

2.) Does the maximum 25 Sim Cards with only 500 KB each per month data enough? That doesn’t seem to warrant 200 euro (without the Cloud of things), especially since I only need one for prototyping with the Sodaq modul that I’m planning on purchasing. Why can’t I just use any other SIM card? I’m rather new using cellular network for communication so I’m not acquainted with it yet.

3.) With the 500 KB maximum data per month, it’s bound that we are to use MQTT so we can send 4 KB of data as payload. I’ve only read up recently on the MQTT-SN instead of MQTT for NB-IoT since you’ve brought it up in your posts. Excerpt from the mqtt.org site:

MQTT-SN is designed to be as close as possible to MQTT, but is adapted to the peculiarities of a wireless communication environment such as low bandwidth, high link failures, short message length, etc.

And it sounds pretty perfect. But can’t we just send data using normal MQTT?

Thanks a lot for your reply! Hopefully we can work together on this, since this project is getting exciting for me!

Hello,

yes, I’m using the NB-IoT & Cloud of Things package by Deutsche Telekom. You will get 25 SIMs with traffic and access to the CoT…

  1. Cloud of Things is based on Cumlocity, a quite powerfull IoT plattform, with dashobards, alarms, event-processing, etc.pp.
  2. good question. 500kb per device per month doesn’t seem to bee a lot, but on the other hand by using MQTT-SN the overhead is quite small. my device is acting as a sensor sending every 10 minutes an update of perssure, humidity, temeprature and gps-position. this is a payload incl. MQTT-SN of 48Bytes every 10 minute. This is about 200kB per month.
  3. MQTT-SN is very close to MQTT, but reduces overhead. CoT is actually only supporting MQTT-SN for NB-IoT devices.

The problem with MQTT-SN and the sodaq shield is, that the arduino Leonardo has only little space for programmcode, so i had to implement a very small mqtt-sn implementation and also had to comment/disable all parts of the sodaq code I did not need.

Hi!

I only recently came back from holiday, and now diving back into everything again.

There were so many questions that I had before, but ever since I received another module as a comparison, a quick start from Deutsche Telekom, and list of AT-Commands from the manufacturer, I feel that I’ve gained a new understanding and also a lot more questions. :smile:

1.) I realized now that the two offers that DT gave, (NB-IoT Access and NB-IoT + Cloud der Dinge) apparently has two different sets of SIM cards. Of which it would seem their Access Point Name is entirely different, and therefore one (or both?) is a supposedly secluded cloud network. What I don’t get is, if… let’s say DT’s competition, O2 and Vodafone makes their cell towers, and makes their SIM cards…would it then be possible for us to use the SIM card to access the data in “the cloud” from the different network?

2.) If the SIM card wasn’t tied to the secluded cloud network, couldn’t we theoretically use make our own Cloud platform using Cumulocity and use that as our device manager?

3.) Could you please share with me your MQTT-SN Library? The new device I am using is an evaluation kit which can directly put AT-commands, but I’d later use an ARM microcontroller to receive information from sensors and send data.

Thanks a lot! I’ll learn some more from your code :slight_smile:

Hi Holger,
you can put the Sodaq to ATmega 2560R3 with almost no changes. No problem with prog space. I just changed the ublox channel to serial3.

Hi Adji,

  1. Yes there are two types of SIM available at DT at the moment, one with an privat APN and direct access over VPN, you have to implement your own backend, and one with access to the CoT (Cloud der Dinge/Cloud of Things).
    The CoT SIMs are hard-linked to the APN (nbcloud.ic.m2mportal.de), you don’t have to change it via AT command - and if you try to change it with AT+CGDCONT= xxx, it doesn’t work.
    And, as far as I know, right now only DT is supporting NB-IoT in germany.

  2. Yes, If you use the “non CoT” SIM you can implement your own backend e.g. based on Cumulocity or any other IoT framework.

  3. Yes, send me your email adress via. PM, I’l send you a ZIP archive with this tiny, but runnig code.

Regards
Holger

Hi Gunther,

yes, of course, but I’m using a small case for the shield, the Arduino ATmega is bigger and would not fit into. An Arduino Uno would also fit in the case but has only one serial, so I stuck on the leonardo.

regards
Holger

Hello @hleshc any news about that MQTT-SN library of yours? Would you like to share it or send it to my email: panik95@yahoo.gr? Thanks in advance.