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).
For RF signal you must draw a 50 ohm net between chip and antenna to get the best performance.This post is the result of my web research on this topic …
There are two ways to design your emitter to antenna solution:
microstrip line
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The way to get a 50 ohm communication way is different depending on your choice.
After some month of use of the Tobeca printer and a lot of time spent to find the right settings, this post is summarizing my experience. I mostly worked with PLA because I was not really fan of using acetone and abs+ acetone mix on a 80°C heating plate, so I’ll not yet detail how to setup ABS, but why not later. So this post is about PLA, about temperature, about adherence and Repetier settings.
BAKU 702B Soldering Station
I wrote a post about the baku 702B 6 month ago with my initial feedback after receiving it.
After 6 months, my feedback is good and the station works well. I just made 45 raspberry shields with it using the air flow and the soldering iron and it make the job.
Now it is time to change the soldering iron head. For sure its life has been short compare to my previous one from another brand. My fear was to find a compatible head as I saw none of them with the 702B reference.
The solution is to search for 936 – 937 station or Tip 900M, they all are the same and works well with the Baku 702B. Go on ebay and pay 1/2€ each ; you will also find different head type. I recommend to order some right after buying the station as they are coming from china (generally) and your need 2-3 week to get them.
CentOS 7 have selinux activated, so when you decide to change your default httpd directories you have to give the right selinux permission to these directories otherwize the https server will not be able to access the files.
I fixed tonight a problem with rfrpi and Raspberry 2+ ; it seems that wiringPi 2.25 have a bug with delayMicroseconds() function that works perfectly when less than 99us and do not work correctly with larger values.
Waiting for the fix the code have been updated to work correctly with RPI2+ ; so please if you are using the shield with RPI2+, update the rfrpi code from bitbucket.
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
Raspberry Pi B+ – RFRPI Shield
I’m proud to announce the compatibility of the RFRPI shield (RF433 transceiver for RPI) with the new Raspberry PI 2+
To get all detailed information about this shield you can read this post
You must use wiringPi >= 2.25 for RPI2+ compatibility.