TD1204 / Sigfox & GPS
Telecom Design provides 4 different chips to support SigFox communications. This post details the differences of each of them in term of functionnalities
All are modules are based on a EFM32 / Cortex M3 micro-controler with 128KB flash, 16KB RAM, ultra low power including a Silicon Labs transceiver. The chip is a EFM32G210F128
Read more for details
Telecom Design LAN capability is a 9600bps rf 868 transmission you can use with the sigfox modem to communicate between multiple TD120x devices. One of the main use is to have multiple sensors communicating to a sigfox gateway. The communication get benefit of the nice ultra narrow band RF transceiver included in the chip.
TD LAN is based on GFSK modulation on 25kHz channels working at 9600bps.
I did really remember where but I read it could reach long distance in the best conditions, so as it could open many opportunities, I wanted to test it in real conditions to see what we could get from it.
Raspberry PI Shiel Hat standard
The SigRPI shield is a HAT standard board providing SigFox connectivity to your Raspberry PI. As it is not certified for this network it can’t be used in production for this usage, but you can use it as a long range RF that does not need certification. I will later details this with a project related to this function.
By-the-way, the purpose of this board is to let you play easily with sigfox. The raspberry-pi offering a really efficient way to code and to make prototypes.
The shield comes with TD1204 (including accelerometer & GPS) of TD1208 (sigfox modem). You can use it with the standard firmware or upload your own one.
The shield can be ordered in the shop section : here
This posts details how to setup it and use it.
This morning, some colleagues helped me to test the rf performance of one of my sigfox tracker. I’m really not an RF expert, I try to improve but there still be a long way to go…
In this design I’m using a TD1204 and a Wurth smd 868 antenna ; I have a 100 ohm impedance net between both (sure it is bad) and LC circuit (that sound not to be the good one – btw).
Sigfox on Raspberry Pi
Based on my sigfox multi-board shield, it is possible to hack sigfox with a raspberry pi. The standard telecom Design firmware allow to use it as a modem. The raspberry Pi just have to send the expected AT commands
Sigfox keyapp
The Sigfox keyapp is a useful tool you can buy or you can get when reaching the Sigfox kick-start session. Basically, this tool send a message each time you click on the button. This allow to check the network availability where you want just clicking on the button. Easy, useful !
The KeyApp have an internal battery, one led, one button. It is refill with the usb connector and it is based on TD1208. The internal firmware is a partial modem ; it can be used as a modem on serial port from a PC but not all the AT command are implemented on it.
My purpose was to modify this tool to send automatically message every 12 minutes. The firmware can be modified and upload on the standard way (take a look to my other posts). For sure by doing a such thing you take the risk of loosing warranty and you do it at your own risk.
To make it works you just have to know some of the cabling.
The battery is by default not powering the system until you switch USR1 to LOW. If you do not do this, the system will only work on the usb power. It means you can switch off the system simply by switching USR1 to high.
Will come soon a basic sample code.
sigfox
I had the opportunity, today, to be at the sigfox kickoff day, in Toulouse, with the company I work for. This is an opportunity to post a summary of the technology as it is today.
Sigfox is a network operator for Internet Of Things running on free frequency band (868Mhz in France). Sigfox is deploying itself network in some countries like France. In some other they have partner to deploy it like arquiva in UK (on going actually 10 biggest cities); abertis in Spain, Aerea in Netherland. Actually some European cities are also deployed as pilot : Munich, Menlo, Milan, Warsaw, Dublin, Autria. San Fransisco & Silicon Valley will come soon this year. The target is to have 60 countries in the next 5 Years. Thanks to the long range radio characteristic of the network, Spain has been deployed in 7 months. As to now, the network does not includes roaming constraints & fee. A French licensed device works in any country where the network exists.
The network is high sensitivity with 2 way communication 140 *12 bytes messages a day uplink / 4 * 8 bytes messages downlink. Each of the messages are sent 3 times on different frequency to ensure it will be delivered. The devices are running ultra low energy with 10-25mW radio power. The technology is plug & play : you do not have any peering process to accomplish to make it works (but you have to activate the device in the backend at least…). Data are sent to a global backend whatever the network provider you are passing through and you have contract with. This backend will let you have access to your data in real time and will execute callback (data post) to you own specific backend to proceed your data.
Limits : due to low bandwidth / small messages architecture, the technology does not allow voice, video … transfer for sure. But it is really fitting security, smart cities (traffic, parking waste, street lights…) monitoring, automatic meter reading, leak detection, billing automation…, tracking & security, healthcare (fall detection, distress buttons…), Agriculture.
I previously write this post on how to use a BeagleBoneBlack as a JTAG (SWD) programmer. It was fun but really slow. I port my code on RaspberryPI and now what was taken 5-8 hours is a couple of minutes.
To connect the SWD connector to the PI use the following schema
Connect SWD to RaspberryPi
I use this peace of code to reflash my TD1204 and TD1208 based both on EFM32 when bricked after unsuccessful update…
Here is the python file to interact with SWD : https://github.com/disk91/PySWD/blob/master/RpiGPIO.py
I hop it will be soon integrated in the main PySWD project as the previous one.
You should check or modify flashEFM32.py file
import array from PirateSWD import * from RpiGPIO import * from SWDCommon import * [...] def main(): busPirate = RpiSWD("", vreg = True) debugPort = DebugPort(busPirate) efm32 = EFM32(debugPort)
To run the Flash program, just launch
# ./flashEFM32.py ../myProgram.bin