Designing bluetooth antenna / transmitter

[GreenAce92]

Hello,

I have a couple of projects that I would like to utilize Bluetooth technology, is it "legal" to access this technology? Eg. build transmitters that are designed on this frequency. How do I make the "handshake" between the android device and my project(s)?

Just a quick research

Bluetooth appears to operate on 2.4 GHz, wavelength approximately 4.92 inches, this is what antennas are based on right? aside from circular/linear polirization/gain... I'm looking for a small antenna say half an inch in diameter/width and a quarter of an inch tall if not shorter... I'm not sure if flat bluetooth antennas exist.

Any helpful tips / links would be greatly appreciated

 

[Sooriamala]

Hai
BT is unlicensed Technology. Hence it is nothing Illegai in using it. But it is Basic ethics not to access unwanted areas

 

[FvM]

Many BT modules have "flat" antennas integrated. Just review the datasheets.

 

[ravindragudi]

I am not sure what you are asking when you say legal and handshake ... BT communication is possible between two devices when both of them have proper BT stack with proper software running in them.
As far the antennas are concerned, review the below links to see if you get what you are looking for -

http://www.l-com.com/wireless-anten...ck-stub-antenna-rigid-rp-sma-plug?cmp=Similar
http://www.l-com.com/wireless-anten...duck-stub-antenna-rigid-90-degree-rp-sma-plug
**broken link removed**

 

[PlanarMetamaterials]

Hi GreenAce92,

In my country (Canada) it is not legal to make your own BT transmitter, hook it up to an antenna you made, and start transmitting. Transmitters need to be certified (By Industry Canada in my case), such that they won't inadvertently drown out other people's WiFi/BT.

For that reason, there are many companies which sell integrated modules (with built-in BT stack, RF Front end, and transmitting antenna) which they have already had certified. You can use these modules all you want. I've found that Bluegiga's BT products are very easy to get up and running, and they have pretty decent modules as well (though not particularly fast).

 

[GreenAce92]

Thank you all for your response. I apologize for the delay in my response.

I have a varied set of interests... currently I'm looking to create a black spray-able "blackbody" that absorbs all wavelengths of electromagnetic energy such that, a person would simply take two electrodes: cathode and anode, attach them anywhere to the "gooey" material, and when solidified, energy will start to flow into the electrodes/away... the idea is that it works like Christmas lights where all of the small micro antennas create energy together and output energy where ever it can go... much like an acid and cathode/electrode situation.

Anyway back to this...

I was trying to make proximity detection bluetooth pins, that you attached to your clothing, and it is integrated with an application on your phone so that when you are walking and primarily as an example, you have headphones in and are blind to your surroundings in terms of hearing; so theoretically someone could sneak up behind you and harm you. But the proximity detection (incorporating doppler effect) would detect someone approaching you... as an example, have you ever walked and were scared by a dog that almost bit you, because you didn't see it, but it was running towards you...

Anyway, much of my projects are out of my reach, both financially and intellectually.

I appreciate your responses.

 

[GreenAce92]

I also began reading about the legalities of transmitting and read that anything below a milliwatt okay... which I believe is insignificant... and that you have to get the certification / licensing.