Doubts on Bluetooth detection

elan_arrHi guys,
As a part of a project work, i am supposed to detect the number of bluetooth devices switched on on a particular road by the people traveling through it. I attached a bluetooth dongle to my laptop and it started detecting numerous devices in a span of 3 hrs. With the intention to further develop this i used another dongle connected to another laptop placed at a distance of one km on the same road(road has no turnings). Now the number of devices detected by the second dongle was far less than the first one.
I then placed both the dongles quite nearby and even in that case the number of matching samples from both devices were really less (out of 50 detected by the first one, only 20 was re detected by the second dongle). I am unable to find the reason for this discrepancy. Can anyone please help me...Is it a problem with the device or with the network...Kindly help me...Thanks in advance..

Bluetooth dongle you have used are from same company and same model or two different dongle?

godfatherBluetooth dongle you have used are from same company and same model or two different dongle?

No...different companies...Accel and Technotech...
(by the way, my subscription for this thread was removed suddenly....any idea why that happened!?..😔 )

elan_arrNo...different companies...Accel and Technotech...
(by the way, my subscription for this thread was removed suddenly....any idea why that happened!?..😔 )

you might have unsubscribe for the thread from your control panel.

Well as you have used different company Module it might have difference in range and capability it might have difference in performance.

godfatheryou might have unsubscribe for the thread from your control panel.

Well as you have used different company Module it might have difference in range and capability it might have difference in performance.

Any idea on how to find the specifications of the dongle...i did not purchase them myself...it was provided to me by my project leader...tried searching in the net but in vain...

elan_arrAny idea on how to find the specifications of the dongle...i did not purchase them myself...it was provided to me by my project leader...tried searching in the net but in vain...

Well the complete Manual of the dongle can give you exact detail you can contact that company and ask them to give details.

godfatherWell the complete Manual of the dongle can give you exact detail you can contact that company and ask them to give details.

fine...thanks for the help sir...

elan_arrfine...thanks for the help sir...

You are most welcome. Looking forward to see you active on this forum and please do share your project progress with us. 😀

godfatherYou are most welcome. Looking forward to see you active on this forum and please do share your project progress with us. 😀

sure...sure..😀

No matter what company the bluetooth device is manufactured they all have the same specifications and their frequency range is in the globally unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band(the distance depends on the power supplied to device).

Then most bluetooth device can work upto 5 meters and they are called class 3 devices and similarly class 2 and class 1 works upto 10 meters and 100 meters respectively. You can choose the class as per your requirements but there is no device that can work above 100 meters.

thats right but then what maybe the cause for the problem i mentioned?. Moreover i found that the sensitivity values of devices differ depending upon the manufacturer. Some have a sensitivity of 80dBm and some have 85 dBm.

i'm just giving you the link where you can get good class 1 bluetooth....#-Link-Snipped-#

elan_arrthats right but then what maybe the cause for the problem i mentioned?. Moreover i found that the sensitivity values of devices differ depending upon the manufacturer. Some have a sensitivity of 80dBm and some have 85 dBm.

praba230890i'm just giving you the link where you can get good class 1 bluetooth....#-Link-Snipped-#

fine...thanks...😀

i have one more doubt. As i said earlier the devices have a sensitivity of -80dBm or -85dBm or in general the specification is -70dBm or better. My doubt is which value is better. I mean like if i have -80 and -85, which is better. Going by basic math -80 is greater than -85. But then the statement "-70 or better" is contradicted!!!...Kindly help me..

Here greater the dbm then better the operation of the device and the negative dbm indicates the loss so we need to use less negative dbm. that's why -70dbm is better also when u compare -80 and -85dbm then -80dbm is better.

elan_arri have one more doubt. As i said earlier the devices have a sensitivity of -80dBm or -85dBm or in general the specification is -70dBm or better. My doubt is which value is better. I mean like if i have -80 and -85, which is better. Going by basic math -80 is greater than -85. But then the statement "-70 or better" is contradicted!!!...Kindly help me..

oh!...fine...thanks...😀