Author Archives: Paul

Gcc – wrap a function in a closed archive

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Here is the situation : you have a function in an archive but you do not have the source code. And you would like to change the behavior of this function or intercept the call to this function.

This is possible with gcc and the -Wl,-wrap linker options. Thanks to this option you can create a new function starting by __wrap_ followed by the function name. This function will be called instead of the original one. In the function you can decide to call the original function by using its name starting by __real_

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Kerlink LoRaWan Wirnet iFemtoCell review

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LPWA networks needs antennas and gateway to receive the device communication and transfer them to a network kernel. You can take a look to my post on the LPWA network architecture for more details.

In the LoRaWan ecosystem we call the first part of this network architecture a gateway. There are different kind of gateway : The network operator gateway with a big and efficient antenna, capable to support external weather like the Kerlink IoT Station and some low costs solution you can deploy at home or within a building (indoor) to cover a local device fleet.

The Kerlink Wirenet iFemtoCell device is a such type of gateway. this post will review how to get start with it and what we can expect in term of coverage.

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The impact of putting an antenna in a box

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IoT design a usually a matter of antenna as already seen in different previous blog post. Antenna performance is the assurance of your capacity to deploy your object in larger zone and a way to save energy by reducing transmission power.

As we will see, if you get a hardware component and simply put it in a box its radio behavior will be totally different as the box is impacting the transmission.

This post will practically show you the impact of a box on a device radio quality.

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miniVNA Tiny Plus review

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I’ve got my miniVNA Tiny+ this summer and start making test with it. A VNA is a Vector Network Analyzer. Behind this dark name, this is a tool able to analyze the radio response of your circuit and ensure your circuit is tuned to the right frequency. From the data measured by this tool you can find the right adaptation circuit to match your central frequency.

For more information about RF circuit matching, you can read this other post.

The miniVNA Tiny+ is a low cost VNA solution less than 300€ covering frequencies from 1MHz to 3Ghz. These frequencies are good for most of IoT need : LPWAN around 868MHz and Bluetooth at 2,4GHz. The steps are 10Hz for a large precision. With two ports you can measure S11 – power transmitted and received over the same port – and S21 – power transmitted from port 1 and received over port 2.

The miniVNA Tiny+ is an usb solution working with a computer connected to and a software running on the computer. The software is based on Java and may support different Operating Systems.

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I-Extruder – solder paste dispenser

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Ordered from Kickstarter and received quickly, this solder paste dispenser really changed my life !! Now since about 3-4 month I’m using it regularly and it still mking me really happy.

It has start from a Kickstarter project I back on but failed the first time. This was disappointing as the classical tool I’m using for dispensing solder paste are really noisy. So when they did a second KS and make it I was really happy. More over they are neighbor of me (about 200km on the Est) and seeing a such good idea made from France is as a good news as a surprise.

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SMD pickup tool review

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Sometime when you want to place a SMD component on a PCB you can use a handy vacuum pump. I’ve tried different low cost model from AliExpress this summer and this post will tell you what is looking best to me for my use.

First of all, I’m not using this tool for components like small resistor, I prefer tweezers for such components. I’m using a handy vacuum pump for larger components like QPF, TSSOP, SOP, QFN…

I’ve tried 3 different tools from AliExpress from 1$ to 9$

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Meet the Sigfox founders

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This last monday I had the chance to meet the two Sigfox founders Ludovic Le-Moan and Christophe Fourtet during a really nice day at Labege (SigFox headquarter) with other Sigfox ambassadors.

From the meeting we had with the founders I retained some of the Sigfox strategical guide line:

 

 

  • Scalability –  this is the major point raised during our discussions : the network must be able to scale and all what has been designed in the radio protocol & technology, as in the cloud architecture was for scalability.

Thanks to this initial design no big change are expected in the radio solution in the coming years. It has already been designed for future.

In regard to this scalability strategy we have also meet the team operating the network. I’ve seen a really nice Network Operation Center, well equiped and with about 40 people involved. It has been fun for me as in my daily job I’m managing internal inter-application communication of a large company. The volume of data we are proceeding every day is quite similar as of now but Sigfox is well more equiped than I am and better prepared for scaling 😉

 

  • Reliability – The ISM band will continue to have more and more noise on it coming from all the coming radio device using it. Sigfox design has been made to ensure a long term capacity to support this evolution. Ultra narrow band is actually the best and secure way to continue to communicate over noisy environment also protecting this common good by limiting the spectral usage.

 

  • Simplicity –  Sigfox has been made to be simple to use with no parameters to tune the radio or the protocol. Everything is defined to ensure a good quality in the communications. This spirit will be kept in the future but potentially we will have the capability to tweak some of the parameters. We could imagine to limit the repetition time for frame with lower criticality. This will save power or send more frame per hour. We could imagine to get higher speed. Why not having more downlink ? Larger payload ?

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Wisol WSSFM20R1 module

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New comer in the Sigfox ecosystem : the Wisol FM20R1.

Wisol have already changed the Sigfox module world by providing a solution based on the OnSemi design for transmitting on Sigfox network for about 2$. Now they are back with a full SoC solution for a really competitive price estimated under 15$. This solution is providing SigFox, GPS, Wifi, NFC, RF and includes an accelerometer.

 

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