Is Bluetooth Communication Possible Without Pairing

bluetooth

I am working on a device which can wirelessly activate a system "instantly". The first thing which came to mind was to use RFID technology which has the advantage of instant and cheap communication. However, I am interested in using my phone's Bluetooth capabilities to accomplish this task instead.

So my question is, to use Bluetooth communication, is there a way to communicate without pairing? In other words, at a very simplistic level, suppose my Bluetooth receiver is expecting a code "abc123". A Bluetooth device, like a phone, is programmed to constantly transmit this code. Upon receipt of the code, the system commences to do whatever it is supposed to once access is granted. Such a system would remove the pairing barrier, of course, at the cost of security.

So is this concept a possibility? I have little understanding of Bluetooth link protocols at a very technical level, but if someone can give me a lead, I can start learning from that point. Do not consider my limited understanding a constraint.

Best Answer

Yeah, it's entirely possible. I commented on this previously and have since looked into it further. You can have the triggering Bluetooth device send the activation signal through its friendly name.

The friendly name is the human-readable name that appears in the the list when you search for a Bluetooth device to pair with. The speed at which this activates depends on how quickly the receiving device polls for friendly names. You haven't mentioned what type of receiving device you're using but I found this PDF (Pg.35) detailing the process for updating the friendly names of in-range Bluetooth devices.

You can poll for friendly names as often as you require. If your triggering device changes its friendly name to the activation code, abc123, then the receiving device will be able to see that name without pairing and activate whatever task you're attempting to perform. This also allows you to have a multitude of activation codes, I think you can get up to 248 bytes for the friendly Bluetooth name.

You may also look into intentionally opening yourself up to Bluejacking. I'm not familiar with it, but if security isn't an issue it could work.