Yesterday in a communication around Securitas Direct deal a small phrase has waked up all the Sigfox community:
Announcing in a certain way the arrival of 600Bps support for Europe (this is already the North American standard speed) to support the picture transfer over the LPWAn network. That said, even at 600Bps it’s a bit complex to transfer a picture… let’s see what we can do with this:
I’m living in RCZ1 (EU868) area and our zone have some specific rules for using the free radio frequencies like duty-cycle to comply regulation I already shared in the linked post. I was little experienced with the US zone regulations. Thanks to a project made for a North American customer I started working on it and I’ve surprised of the differences and how it impacts the LoRaWan developments.
In my previous post I explained how to communicate on LoRaWan with the Murata CMWX1ZZABZ module. This module is capable to support Sigfox communication also and this time we are going to see how to do it !
Murata CMWX1ZZABZ chip is actually famous for being a powerful LoRaWan multi zone module also able to communicate over Sigfox.
I’ve already published a technical post on Murata CMWX1ZZAB chip in a previous post. You will also find an implementation based on my IoT SDK. Yadom has just released a breakout board ( BRKABZ01) for this chip making it accessible for hackers and for easier prototyping.
This post is going to review this board and demo how to access it really quickly. Are you ready ?
ST Micro-Electronics is providing a development board with a Murata CMWX1ZZABZ-091 chip. This device is a module containing a STM32L0 chip (192Kb of Flash / 20Kb of RAM) associated with a Semtech SX1276 radio chip. This module can be used as a SoC for developing LoRaWan IoT devices. The Semtech chip is also capable of Sigfox. This module is a bit expensive but it is actually the one allowing LoRaWan and Sigfox communication in any of the RCZ zones.
Sigfox is not publishing its detailed specifications. For this reason different people (like me) are doing reverse engineering. Thank to this activity we are now getting more and more information on how the IoT network communication works. I’ve been the first one to publish the uplink frame in details more than a year ago.
Today, during the 35th edition of CCC Congress, Florian Euchner has published, on Github, the first Open-Source Sigfox stack : LibRenard.
This library allows to transform a Sigfox radio signal into a decoded frame (uplink demodulation). It allows to create a Sigfox radio signal from a decoded frame (downlink modulation).
The LibRenard implementation follows the Open Sigfox Protocol specification also host on Github from Florian. It details the uplink as the downlink communication frames. Making this open specification as the real first Sigfox global protocol specification published.
I really want to congratulate Florian for this excellent work. I hope the stack will be soon enriched with the native Sigfox encryption I’ve just finished to detail, with the associated OOB frames.