Category Archives: Technology

Tips and test on technological product and components. Operating system, networks, hardware, security…
Astuces et tests autour de produits et composants technologiques, systèmes, réseaux, hardware, sécurité …

Measure waveform duration with EFM32 / TD1208

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tim10Measuring a pulse duration in a pulse train was my last week headache with the TD1208 and the not so well documented EFM32. Basically, my objective was to activate a timer on a pulse train to measure the duration of the pulse. This duration was measured about 100uS and occurred at 1 Hz.

My choice was to rise an interrupt on each signal front (raising and falling) and measure the duration between the two first interrupt call. Some reset function ensure we are measuring the low state duration (100uS) not the high state duration (1s). This part will not be described here.  The purpose of this post is to describe the main hole I fallen in.

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Simple LoRa GPS tracker based on RN2483 and L80

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LoRa GPS Tracker

LoRa GPS Tracker

Todays work was to make a simple GPS tracker communicating over LoRaWAN to check the coverage of my LoRaWan gateway in the city. Basically this tracker reports a position per minute to the network. If coverage is good, position will be recorded in the backend. That’s all !

This post details how to do it easily with the low cost and common components : Arduino for the master, Microchip RN2483 for LoRaWan communication and L80 for GPS positioning.

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LoRa / TheThingNetwork – Install you own backend

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In a try to connect my LoRa gateway to a standard backend, I started to install TheThingsNetwork software stack. Even if I did not finish it because it was not compatible to my gateway protocol, here are my starting notes … May be completed later.

 

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LoRaWan experimentation with Kerlink gateway

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kerlink LoRa gateway

kerlink LoRa gateway

Until the reality of a LoRa public network in France, to test this technology the best way is to have its own LoRaWAN getway. This is a thing done with the kerlink gateway.

This post will detail the first steps to install it and start to communicate.

 

 

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RN2483 – LoRa – upgrade firmware

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Microchip RN2483 Lora

Microchip RN2483 Lora

The microchip device is in most of the case delivered with a 0.9.5 a version 1 seems to be available even if not downloadable from microchip product webpage.

This link contains a version 1.0 and a java tool that helps to configure the chip with a graphical interface. It is really usefull.

Main problem I found with the tool: it is not possible on a MAC to open the firmware file to load. Other functions are accessible. On W7 it is possible to flash the device :

 

  • Connect the device with bootloader mode check activated
  • Select the firmware hex file
  • Select 19200 bps as for speed
  • Clic … sometime it is short (and not working) sometime it is longer and working
  • At end, execute a hard reset and search for the module it should appear.

Actually on May 1st 2016 the current firmware version is 1.0.1 you can get it following this link. This version is the one validated for network operators like Objenious.

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Flash a TD1204 over J-Link

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For flashing a TD1204 / TD1208 over J-link you need to use the following commands:

JLinkExe -device EFM32G210F128 -if swd -speed 1000
J-Link> loadbin xxxxx.bin,0
...
J-Link> r                          # reset
J-Link> g                          # go

Total programming time is about 5 seconds. The circuit between the segger connector and the TD is the following one. (do not forget to connect VDD circuit to Segger VTref.

td1204 / j-link cable

td1204 / j-link cable

Get computers for less than $15

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domino.io

domino.io

Announced in 2015 and mostly delivered in 2016, the 9$+ computers are now a reality. The first one  to be delivered was Domino.io with a price of 14$ it is actually the most expensive device but also one with a nice list of addon. The kickstarter campain was a success even if it raised only 46K$.

CHIP was in the same period of time a great success with 2M$ raised on Kickstarter for 50K requested. And actually it still incredible to me to reach a such cheap price for a device with a such complexity.

Last but not least, the famous RaspberryPI zero is just starting to be distributed at the incredible price of $5 and is actually impossible to obtained under $20 on ebay auctions.

As a owner of these 3 different platform, I will publish in this post the difference we have between them and what we can expect from them.

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Getting start with XYZ DaVinci 1.0 3D Printer

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DaVinci 1.0 3d printer

DaVinci 1.0 3d printer

After having play for a year with a Tobeca Printer, I decided to acquire a DaVinci printer. When I was looking for the Tobeca I was already interested in the DaVinci because of its really low cost. At this time, this printer was not available in Europe and the price for import was too expensive. The printer is actually distributed by Boulanger in France for a price about 500€ making it a really competitive solution with a good technical specification.

The XYZ business model is based on 2D printer business model : have a low cost printer and sell the cartridge at a higher price. For 800g of PLA you have to pay 50€ compared to 30€ for a Kg of standard PLA. By the way, it seems that you can get discount on Wednesday on XYZ website 😉

This post details my end user experience on getting the first print with this printer.

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