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.

 

The OnSemi chip exists in 2 different versions (for the ETSI zone I mean) – a modem version you can’t program and a SDK version you can eventually program (I will let you know later how it works and the difficulties I’m actually having with it). The chip also exist for FCC area and another module from Wisol exists.

The Wisol WSSFM10R1 module is in fact a OnSemi, ETSI, modem version implementation in a module, not more, not less. The good point is that OnSemi implementation to respect CE requires an exact replication of the reference design with really small smd components and this module remove all this complexity for your design. The chip is CE certified and your object certification may be really more simpler using it.

The second good point is the price even for small quantity and the reactivity of Wisol company to deliver the product (ordered, ship and received in 7 days from Korea) Really good job guys.

Finally, most of the price I payed was transportation (40€) and customs (40€) but the 10 module units where about 25€. I also bought a development kit, really accessible also (35€)

The development kit is simply a module with and FTDI chip and some leds & switch connected to the GPIOs. I need to explore more what we can do with it but as basically the modem version of the module can’t be flashed with custom firmware I’m not sure we have a big interest in using these extensions. I assume a SDK version will coming later and allow a larger use.

Its is really easy to use the kit and you can send you first sigfox frame in a minute…

 

The module itself is small and thin, here are some picture to compare them to a TD1208, just limit your comparison on size as the TD1208 offer many more options thanks to its powerfull SDK.

The module have it pad on the bottom as the previous version of TD1208 and it not have any good elements to ensure you place the module correctly. This point is in my point of view the only bad point of this design because I know, when you solder your component manually, you have a lot of problem and PCB loss due to the difficulty to correctly place the chip.

Once industrialized it is not a problem but for prototyping it is.

 

 

 

To get start with this module, you just have to connect the dev kit to your serial port and launch a serial console. The communication is a classical 9600bps communication. The device receive AT commands.

The first thing to do is to get the Sigfox ID and the Sigfox PAK to be able to register the device in your backend (the devkit seems to not be provided with a sigfox contract so you need to have some at first)

AT$I=10              // Return the SIGFOX ID
001Axxxx
AT$I=11              // Return the SIGFIX PAK
EDA26E1B208xxxxx

You have to note that in a industrial point of view, you need to extract these IDS from the chip and create you own database for a later registration of your product. This is a little bit complicating your industrial process compared to Telecom Design solution who is printing the ID on the chip.

Once your device is registered in the sigfox backend you can send a message on the network by using the following AT commands :

AT$SF=01020304                       // Send 01 02 03 04 
OK

AT$SF=010203040506,1                 // Send 01 .. 06, expecting a downlink
ERR_SFX_ERR_SEND_FRAME_WAIT_TIMEOUT     // got this when no downlink is received

AT$SF=010203040506,1                 // Same thing
OK                                      // got this when a downlink is received
RX=00 00 0A E1 00 00 FF 8F              // with the 8 bytes of the downlink value

We can also get some classical information from the chip like the temperature

AT$T?              // Get the temperature
0272                  // 27.2°C ... Totally wrong 
                      //            the real one is 20°C

Temperature is not good as we are used to have for such sensor but worst than I ever seen with more than 7°C. The documentation indicates an error of +/-  2°C the reason seems to be the FTDI chip : it is warm and may warm the whole devkit.

You can also measure the power supply voltage :

AT$V?                // Get the current Voltage
3305                    // 3.305V current Voltage
3305                    // 3.305V last transmission Voltage

According to my Voltmeter the value is 3.315V. This sounds good.

About power consumption : the device in standby is basically consuming 0,5mAh… so it is huge !! But you can reduce it drastically by changing the sleep mode:

AT$P=1                 // switch to sleep mode : consumption is < 1,5uA
OK

AT$P=0                 // switch back to normal mode : consumption is 0,5 mA
OK

You can also go out from sleep mode by sending a simple CR on the serial line. I assume any interrupt will wake-up the chip. So you just have to not forget to put your device on sleep after a transmission.

An auto sleep mode would be a nice update for a later firmware release. A deep sleep is possible to go lower the 1uA. wake up is possible with putting GPIO 9 to GND.

To conclude :

• Plus of the product : really low expensive module, really fast delivery and perfect service from Wisol to deliver. Small size, CE certified. Ready to be used in a minute.
• Minus of the product: package really hard to solder for prototyping. Ids requiring a serial access to be extracted from the chip.

They are planning for more complex product integrating axel / gps / ble… let see what will be the price and what support we will have. Actually this module does not require a lot of support from them as all the software part is provided by OnSemi.

The OnSemi datasheet is accessible on this link and have all the AT command listed.

The wisol website is accessible on this link

Global note of the WISOL Dev-Kit : 4 (****) / 5
 
Public for WISOL dev-kit
- beginner makers : *
- average makers  : **
- advanced makers : ***
- educational : *
- Pro : *****
   
Prototyping capability of the product 
- **
  Limited to Sigfox functions 

Quality of dev-kit 
- *****
  Industrial grade devkit

Quality of the documentation 
- ***** 

Capability to be integrated in a prototype 
- *

Pros 
- Price 
- Quality and accessible functions 
- Immediately ready for use 

Could be better 
- Nothing specific