DZone Snippets: hcitool code

Detecting bluetooth devices with hcitool scan

jrobertson (James Robertson) — Sun, 13 Jul 2008 22:31:47 GMT

A trivial Ruby script to store the bluetooth devices found with the shell command 'hcitool scan'.



#!/usr/bin/ruby



#file: bt_scan.rb



require 'rexml/document'

include REXML



while true

  filein = File.new('bt_found.xml','r')

  doc = Document.new(filein)

  filein.close



  fileout = File.new('bt_found.xml','w')



  result = `hcitool scan`

  found = result.split(/\n/) # retrieve each found device

  found.delete_at(0)         # remove the item containing 'scanning ...'



  found.each do |b|

    node_found = Element.new('found')

    p = b.split(/\t/) # retrieve device details

    id = p[1]

    name = p[2]

    puts "name #{name} --- id #{id}"

    node_id = Element.new('id')

    node_name = Element.new('name')

    node_date = Element.new('date')



    node_id.text = id

    node_name.text = name

    node_date.text = Time.now



    node_found << node_id

    node_found << node_name

    node_found << node_date

    doc.root << node_found

  end





  fileout.puts doc

  fileout.close

  puts 'sleeping'

  sleep 10 # during this time we can kill the script, 

           # otherwise we risk losing the contents of the xml file.

  puts 'awake'

end

Note: Shell commands don't really have much to do with Ruby, however if there is no easy to use bluetooth libraries then I will of course use what's available.

Using Ruby to detect Bluetooth proximity

jrobertson (James Robertson) — Sun, 25 May 2008 10:57:00 GMT

This Ruby script uses the hcitool and rfcomm to detect the proximity of a bluetooth enabled mobile phone. The signal strength in this script will return a value from 0 to 10, 0 is near and 10 is far, otherwise if there is no connection it will keep on trying.



deviceid = '00:12:D1:E6:57:BE' 

range = ''

count = 0

while count < 1

  # assuming the bt device is already connected get the signal strength value.

  range = `hcitool rssi #{deviceid}`.chomp

  if  range.length > 0

    puts range[/\w+$/]

  else

    puts 'connecting to the bluetooth device ...'

    Thread.new{`rfcomm connect 0 #{deviceid}`}

  end

	

  sleep 7

end

warning (11-Jul-2008): I've found Thread.new to be causing a problem, it appears not to remove itself from the process queue when it is no longer required.

Simple Bluetooth Proximity

jrobertson (James Robertson) — Tue, 20 May 2008 22:39:59 GMT

Following on from my earlier investigation into bluetooth proximity, I wanted something which returned a value which could be used to determine distance. The output from hcitool rssi ranges from 0 for close object down to -10 for far away objects.



rfcomm connect 0 00:12:D1:E6:57:BE



hcitool rssi 00:12:D1:E6:57:BE

Proximity Results:
-4 .. 0 : Bedroom - nearest to my bed
-4 .. -6 : Hallway
-8 .. -9 : Livingroom - on the computer desk
-9 .. -10 : Livingroom - nearest to the window

Detect the presence of a Bluetooth device

jrobertson (James Robertson) — Thu, 27 Dec 2007 15:11:41 GMT

This example shows how to check for the presence of a mobile phone. The code was based on the article 'Implementing Bluetooth Proximity Detection with Asterisk, Part II' http://snipr.com/1vvi5 [nerdvittles.com]



#!/usr/bin/ruby

#file: whereib.rb



deviceid = '00:0E:6D:29:38:EB'

devicename = 'Nokia 6600'



count = 0

while count < 1

  if `hcitool name #{deviceid}`.chomp == devicename 

    puts devicename + ' IN RANGE'

    puts Time.now

  else

    puts devicename + ' OUT OF RANGE'

    puts Time.now

  end

  sleep 7

end