Bluetooth device and Dongle





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Sat, 06/14/2008 - 14:23 — harishnair86

A blue tooth phone with 10m range cannot communicate with a blue tooth dongle of 100m range if the distance exceeds 10m.Is it true?
Then,what is the use of a blue tooth dongle with high range(100 or above ),when we are setting up a blue tooth hotspot, since communication beyond 10m won't be possible?
Can anyone give a proper explanation on whether this is true or not?


Bluetooth phone can communicate to Dongle whose distance greater than 10 meter.
Sun, 06/15/2008 - 08:02 — amitz27

To my knowledge a bluetooth enabled phone can communicate with a PC dongle even if it is more than 10m away.

Let me explain this

Bluetooth works by a process called device discovery and service discovery. ie It scans for any other bluetooth devices nearby and connect to any service compatible(like file sharing, chatting etc).

This connection is created by a handshake between the 2 devices.

So When we search for a device via Donge, since the device discovery is happening in a radius of around 100 meters, all the devices which are in that 100m radius are picked up.

Similarly in the case of the phone, although its range is limited to 10m, since the range of the dongle comes in that 10 meter too, the phone is able to receive the handshake signal and connect to the dongle.

So I believe using a dongle you can definitely increase the range of the Mobile bluetooth.

I had done my major project on bluetooth, and I have experienced the same.

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Doubt about your reply-Mr amitz27
Sun, 06/15/2008 - 22:54 — harishnair86

Thanks for ur reply.I agree with what you said about communication from dongle to the device but in order to confirm the handshake,should'n't the mobile phone send the signal directly to the dongle that is 100m away,which is obviously not possible with the range of a mobile phone!I had tried this mode of communication(i.e from PC with 100m dongle to a mobile phone) but as soon as mobile moves out of 10m range,data transfer fails!What about that?

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U have put me in a dilemma!
Mon, 06/16/2008 - 21:59 — amitz27

Well if you have tried it and failed then I have nothing to say. my knowledge was the other way. Thank you for pointing it to me, now i can change the wrong assumption I had ;)

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About your answer-amitz27
Tue, 06/17/2008 - 10:21 — harishnair86

I thought,you would have some explanation for that!Because of this problem,that hotspot project wasn't effective!
so it seems that i may be right about that!but still it makes me mad-"What is the dongle for?"
Ok thanks..not confusing you anymore!

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Dongle is mainly for PC to PC connection
Tue, 06/17/2008 - 13:20 — Guest

@ harish

To my knowledge donge is used for PC to PC connections mainly. In that respect we get an effective range of around 100+100 ~ 200m (In the ideal condition).

Mobiles use bluetooth chips capable of only 10m range and mainly the dongle was not made to make 'mobile to PC connections', it was just to extend the connectivity of the PC through wireless means.

Even I had dealt with a project regarding bluetooth in which the basic idea was to set up a bluetooth network in which mobiles will be able to connect to other mobiles at a distance of more than a 100m!

Well we had done a lot of work in that. The basic principle was to use hoping and connect to the destination nodes via an intermediate one.

ie if there are 10 mobiles placed 10 m apart,

A -> B -> C -> D -> E -> F-> G -> H -> I -> J

All ARE PLACED AT A DISTANCE OF 10M APART, then the message can be sent from A to J via passing it through the intermediary nodes B,C,D,E,F,G,H,I.

THIS WAS THE LOGIC WE IMPLEMENTED. Using this we could easily overcome the limitation of the 1m bluetooth range and could virtually create a Bluetooth LAN.

Just think about a building fully connected with bluetooth! Free file transfer, free messaging, free calling!

Thomas

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@Thomas
Tue, 06/17/2008 - 16:02 — harishnair86

Thanks for your reply!But is using a no: of mobile phones sensible?Also in order to work effectively,these mobiles should also have good java programs that are efficient for  token passing like architecture that you had mentioned!Did the stuff you mentioned work efficiently?
Also,instead of that,   a-10m-(B)-------100m---------(C)--10m-d
here a and are mobile phones while b and c have computer with 100 dongles....hw abt dis?so here (B) and (C) can act as hotspots naa?Do reply about this....

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Yes it can - Hot spots are an option
Fri, 07/04/2008 - 20:06 — amitz27

Hi hot spots are a definite option. in our case what we planned to do is to connect a building as a whole (basically a college building) and in no way are they going to allot a PC for this! It will be a major distraction for all ;)

They are getting free messaging na!!!

So we thought of using phones only.

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