I just got them at home ! The new Sigfox module with a low cost approach based on the OnSemi AX-Sigfox-D chip is now ready and available for being delivered. With a price less than $3 per module for a quantity of 10 this module offer a low cost access to the Sigfox network.
In this post I’ll describe the first step with this module.
Since a long to time I did not post about MQTT … The main reason was I uses MQTT as a protocol to publish data directly from a device but in a centralized environment like SigFox / LoraWan you can’t use it directly on the device. Actually I have some devices communicating with a backend and the question about how to provide these information to the customers of my service are raising. To match this pattern I have to ways : providing and API where the information are pulled by the customer and MQTT where the information are pushed to the customer.
One choice is not against the other one, I had the two kind of customers. For this reason I will describe how we can implement a MQTT server (mosquitto) to push Sigfox data device as json content.
I’m using different GPS antennas with different price, size and gain and I had never compared the result in a real live test. So now it is done and the result are good to share.
My test condition are quite bad and we can’t really consider this as a scientific bench but, experimentally it sounds like a real life test.
So the test is to connect an antenna to a TD1204 with a GPS code on it and test the time it makes to fix the position and get some note about signal level, satellites in view… I used in fact 2 TD1204 : one with a reference antenna to ensure we have equivalent condition from one test to the others. The tests are made indoor where the sensitivity is an important factor. This post detail the results.
I have recently discovered the smartEverything prototyping board for Sigfox. This board was used during the SigFox maker tour and It is really nice for creating some prototypes and evaluate the technology.
The board is an Arduino board based on an Atmel SAM D21 MCU (Cortex M0) with 256KB of flash and 32K SRAM running @48Mhz
The most important part is concerning the sensors available on the card and this is clearly the best point about this board : you have a lot of them available : crypto authentication chip, BLE module, GPS, NFC, Accelerometer / gyroscope / magnetometer, Pressure / Humidity / Temperature sensor, proximity light / sensor, RGB Led, Led & push button. It can be powered by USB or external 2xAA batteries.
The board cost is about 106€ and can be found at RS. It is provided with a sigfox network access to the backend.
This post detail how to get start with the board
After making my kit on my own, I finally got the official Telecom Design TD1204 kit (thank you TD) There is no big issues to use it once you have the right entry point, but as I had some email exchange with support to be fully ready for using it, I’m prefer to share some words with you on what to do and how it works.
Basically, the TD kit is an EFM32 Tiny Gecko Starter kit (STK3300) with some little modifications. The EFM kit have two interesting functions : in own a Jlink JTAG/SWD programming and debugging interface and its EFM32 MCU can be use to monitor power consumption with precision.
I needed to access a mongodb instance to manage my collections. I was looking for something like phpmyadmin for mongo but the first tool I found was mongoclient.
This tool is an application for desktop provided for many OS including mac OsX. The quality of the tool is really good.
The mongodb was installed on my server remotely and protected by a firewall so the easiest way to access it was to open a ssh tunnel. Mongoclient is supposed to manage the ssh tunnel in the application but it was not working for me so I had to manually connect the tunnel :
# ssh -L 27017:localhost:27017 -p 22 user@mongodb.server.com
Once connected it is possible to create a localhost connection with mongoclient.
TD1204 / Sigfox & GPS
New version of the Telecom design SDK has been released for TD1208 / TD1208R / TD1204 and now officially supporting TD1205.
This new version provide some bug fixes, like a crash after 21285 transmissions that could be after 212 days in case of full use… some I had in touch with could be interested… @pioupiou and also a bug that disable gpio interrupt after sigfox transmission (I experimented it !)
For the main evolution, this version is supporting FCC and TD1508 and improving sigfox transmissions.
From my experience, this version is also a good way to decrease the size of your binary files.
This post is about upgrading from a SDK 5 to SDK6 and the impact you can when recompiling your projects.
To install the SDK from scratch, just follow the well documented official post here.
I’m actually doing some experiment with the French LoraWan network operated by Objenious. To receive the message on your backend application, one of the way is to build a callback function to proceed the data.
Due to LoraWan protocol, you have different type of possible callback like for: joining network, uplink messages and downlink report.
This post gives an exemple on how to implement an uplink message callback handler, with php, for your application backend server.