To prepare a presentation of MQTT for tomorrow, I just finished a MQTT / Mosquitto demonstration in a 4 minutes video. Enjoy !
How to use MQTT the 4 minutes tour
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Tag Archives: IoT
Create a connected PIR sensor with SigFox
Pir sensor
In a previous blog post I described how I built a PIR sensor connected to Internet, based on the use of a Raspberry Pi device. As you can read in this previous post, the solution have a certain number of complexities like requiring a power supply, a 3G modem …
As it was originally planed to be done, here is the design of the same product, based on a SigFox device. This is really interesting to demonstrate the differences and the advantages of this technology. Let’s review how to built it !
Create a 3G Pir sensor with a raspberry Pi
Raspberry Pi 3G PIR sensor
Basically, it is something I was looking to do with SigFox, but unfortunately yesterday I bricked my chip because of a wire unsoldered right in the middle of the upload of a new firmware version … By the way, I’ll do it later once it will be fixed.
So I had to built it on a raspberry as a short term solution. Read next to get details
What about TD1208 / Sigfox current consumption ?
In a previous post about SigFox technology, I told I will measure the power consumption to see if the device can be use with a battery easily. And what I can say is that they have made a great job on power saving with this device.
What I measure (with my really low cost multi-meter) is a standby consumption of 2uA and a transmission power of 45mA. The transmission of a message is not depending on the size of the message and is about 7s. As you can transmit up to 1 message every 15 minutes, the communication consumption is an average of 0,35mA/h.
Assuming battery from 750mA to 2500mA this is an autonomy from 4 months to 10 months. It’s a really interesting duration on battery and not comparable with a 3G communication system.
Now … testing is finish … I’ll start to implement a first POC for a project !
Hack fun !
Using Sigfox callback API to create your own application
In different previous post, I explained what is SigFox technology (a radio-communication system made for Internet Of Things, allowing a sensor to communicate with servers on Internet at an affordable price) and how to send data from a sensor to the SigFox backend.
This new post is explaining how to configure this back-end to get the sensor data loaded in your system and create your own application.
Customize you SigFox TD1208 with SDK
As described in a previous post, TelecomDesign chip can be customized to add your own application built-in the chip and made a really affordable IoT platform. This blog post is describing the first step to start building it. Read Next for details.
Let’s start playing with sigfox technology
I already wrote some stuff about Sigfox here, so may know that it is a really promising French technology IoT oriented. So I have a project to connect a Raspberry Pi and arduino system on a such peripheral. The use of this technology is quite easy as it works like a modem, based on AT command transfered over a 9600bps serial line. The main issue is that the chip is really CMS and hard to hack at home easily… by the way, as you see, a poor soldering makes it working for the test purpose.
As much as I have test, I can say that using this device to communicate with an Arduino or a PI is really easy ! code can be written in less than a minute ; compared to what you have to do to make wifi / Ethernet / GSM working in a stable way, this is incredibly easier ! You can also use the device as an autonomous sensor for temperature and contact switch of your choice for an affordable price. In my point of view one thing is missing : you do not really know the signal quality and if you have a good connection or not with sigfox network. [update] The RSSI is indicated in the SigFox Api on the backend side for each of the received messages [/update] . Meaning you must receive the first one to know if the location is covered or not. This can be a problem to deliver a product and get an easy support to your consumer. The other limit of the technology, as much as I know is that you can transmit data but not receive some from the SigFox network [update] The ability for the device to receive messages will be soon added with limitation, but it will [/update]. In many case it is enough but sometime you like to respond to a specific value received. Read next to get details on how to use it …
Do you know sigfox ?
SigFox is a French radio frequency technology allowing a really low cost data transfer from Machine to Machine. Compared to GSM, this solution have some great advantages : it costs only 10-16€ per year and the energy consumption is about 1000 time less. For sure there is some constraint and the main one is the quantity of information you can transmit. In fact you have a limit of 150 sent messages / days with a length of 12Bytes. It’s not big but is it enough for a lot of IoT and M2M applications.
This technology works as a modem you can connect to any platform like Arduino, RaspberryPi. The chips are provided by TelecomDesign from a cost about 15€. The starter kit is about 150€ here.
The great advantage of this technology, in a operator point of view is the low density of the architecture where you need only 1000 antennas to cover a territory like France. As a consequence, at this time, already 90% of the country is covered by this technology.