I want to share with you the DECT Shield for Arduino which allows transmission of data and audio between similar shields and other DECT capable devices such as home cordless phones. The Shield was developed as part of my thesis for my MSc degree.
DECT (Digital Enhanced Cordless Telecommunications) was introduced in Europe in the early 1990’s and was used for creating cordless phone systems. This technology allows the transference of audio reliably and interference free up to 100 meters (outdoors). Nowadays it is present in most home cordless phones, in large scale business telephone system and in baby monitors for example.
The shield is equipped with a Bithium DECT Module which has all the necessary components to make DECT calls and data transference possible. Arduino communicates with the module and the memory card using SPI.
The shield requires pins 8 to 13 from the Arduino to function. Pin 2 can also be used to trigger module events on the Arduino but it isn’t mandatory. Other SPI modules can be used on pins 11 to 13.
A headset with a microphone and a speaker can be connected to the shield to perform calls. A standalone speaker with at least 4 ohm is also allowed to be connected to the shield without requiring other external components to function.
The main features of the shield are:
-> Reliable audio transference between two or more modules at least up to 30 meters;
-> Low data rate transference up to 1.2kbit/s;
-> Connectivity with other DECT devices;
-> Direct playback of audio files from a Micro SD card;
-> Dual firmware system allows it to work as Basestation or Handheld;
-> Easy to understand Arduino API.
The main features of DECT are:
-> Interference free communications up to 100 meters;
-> 1880MHz to 1900MHz frequency range;
-> Up to 120 simultaneous duplex channels;
-> Uses TDMA and frames of 1.728MHz;
-> Suitable for low power applications (average consumption of 10mW).
Graynomad:
I have no use for this but it looks like you've done a real nice job there.
What's the range?
You should get it added to shieldlist.org, although it seems Jon has something of a backlog there.
Rob
Hi Graynomad,
Thanks you, I will remember to add it.
The average range is 100m outdoors without obstacles.
I also did some testing indoors and was able to get a good reception at a distance of approximately 30m.
geschnei:
Nice work, and just what I'm currently looking for. Do you have schematics for it online?
Regards,
Gerald
Hi Gerald,
Sorry for the delay.
A PDF with the shield schematic can be downloaded here.
Unfortunately I cannot release the API just yet because there are still some bugs I need to correct. When ready I will post a replay here with the code and documentation.
Looks great! Where is it possible to purchase the Bithium DECT Module (or equivalent)? I've done some Googling with no luck.
I'm interested in creating a wireless DECT bridge so that I can have a wireless telephone socket.
Looks great! Where is it possible to purchase the Bithium DECT Module (or equivalent)? I've done some Googling with no luck.
I'm interested in creating a wireless DECT bridge so that I can have a wireless telephone socket.
Thanks in advance.
Regards,
Michal
Hi Michal,
Unfortunately the Bithium DECT Module isn’t available.. yet!
Bithium is finishing the second revision of the module and will reveal it to public later this month. If everything goes as planned it will be available for purchase in the next coming months.
In the photos shown I am using their prototype module which is why there are some green bounding wires to correct some differences.
Judging from the lack of a reply on this forum and from Emails sent to the shield board manufacture, I must assume that this project has run into a problem and the unit is not in production.
If anyone knows what has happened to this project or has managed to purchase the DECT module or the completed shield board, please post the details here.
I got email from them and they told that they don't have assembled boards in stock at the moment. They will have updated version in some month and they can start to deliver new boards beginning of September.
OK, we are in mid September and I have not seen any mention of the new DECT shield. Does anyone know if it has been released, does it work, and where it can be purchased?
I really would like to experiment with this unit.
I'm looking to create an Arduino project for doing DECT walk-around survey to determine signal strengths and best place for locating DECT base stations within offices and factories.