bash script that detect iphone proximity and takes actions when it arrives/leave range. This example terminate all SSH sessions on server where it is running when iPhone leave range.

ip_scan_bl.sh

#!/bin/bash

# Script that detects arrival,presence,departure of iPhone based on bluetooth. It also execute actions
# In this script it terminate SSH sessions when defined device lefts range
# Requires: bluetooth, hcitools, curl
# Written by Zbyszek Żółkiewski, please visit: http://blog.onefellow.com
# Install:
# - copy ip_scan.sh to /usr/local/bin/ on your local machine/server
# - chmod ugo+x /usr/local/bin/ip_scan.sh
# - change 'ip_iphone' variable to point you your iPhone mac-address
# - pair iPhone with your linux/whatever machine you want to perform actions/detection
# - option: insert your boxcar_id otherwise comment-out boxcar_send function in action_after_grace
# - put into cron: echo "*/1 * * * * root /usr/local/bin/ip_scan_bl.sh" > /etc/cron.d/iphone_scan_bl , or whatever user you want

# bluetooth mac
ip_iphone=""
iphone=$(hcitool rssi $ip_iphone > /dev/null 2>&1;echo $?)

# logfile
log_file="iphone_scan.log"

# action on away is not done before this N run of this script
grace_t="3"

# optional boxcar id
boxcar_id=""
boxcar_psh="PI: SSH shell terminated"
boxcar_tit="iPhone left known network"
boxcar_lng="Details: You just left appartment and SSH sessions were terminated."

# functions
say_log(){
	
	# write timestamp and output to logfile
	date "+%Y-%m-%d %H:%M:%S $1" >> /var/log/$log_file
}

action_arrive(){

	# perform action on arrive
	say_log "Welcome Professor!"
}

action_left(){

	# perform action on left, maybe you want to close windows or doors?
	say_log "No Action"
}

action_after_grace(){

	# perform action after extended absence
	ps ax | egrep "sshd: [a-zA-Z]+@pts" | awk '{print $1}' | while read ssh_pid; do
		say_log "Action: Killing SSH PID: $ssh_pid"
		kill $ssh_pid
	done
}

action_away(){

	# disallow any SSH users if iPhone is not authorized in local network
	check_ssh=$(ps ax|egrep -c "sshd: [a-zA-Z]+@pts")
	if [ "$check_ssh" -gt "0" ];then
		say_log "Warning: SSH sessions found. Terminating all logged in users"
		action_after_grace
	fi
	# avoid printing anything, as it just poison logfile
}

boxcar_send(){
	curl -d user_credentials=$boxcar_id \
	-d "notification[message]=$boxcar_psh" \
	-d "notification[long_message]=$boxcar_lng" \
	-d "notification[title]=$boxcar_tit" \
	-d "notification[sound]=21.caf" \
	-d "notification[silent]=0" \
	-d "notification[message_level]=1" \
	-d "notification[action_loc_key]=read" \
	https://new.boxcar.io/account/notifications.xml
}

# end functions

# check if state changed...
state_c=$(cat /tmp/iphone_present)
if [ "$state_c" != "$iphone" ]; then
		ip_state="same"
	else
		ip_state="changed"
fi

# 0 - hci successful, 1 - with error (no signal,power off, etc..)
if [ "$iphone" = "0" ];then

		# Check signal strength. Tune to your needs 
		rssi=$(hcitool rssi $ip_iphone |awk '{print $4}')
		if [ "$rssi" -gt "-15" ]; then
                		range="close"
        		elif [ "$rssi" -lt "-14" ]; then
                		range="away"
		fi

		# Got signal, if state is same as before we know iPhone was already here	
		if [ "$ip_state" = "changed" ]; then
				
				# state changed, and it is new, so we know iphone just appeared in net
				say_log "iPhone just arrived! Range: $range [$rssi]"
				# perform action on arrive
				action_arrive

				# set markers
				echo "1" > /tmp/iphone_present
				echo "0" > /tmp/iphone_action
			else
				# state same, iphone was already here
				say_log "iPhone is present on network. Range: $range [$rssi]"
		fi
	else

		# No signal, error, whatever go wrong with bluetooth lead here, check if it is known state
		if [ "$ip_state" = "changed" ]; then

				# New state - this looks like iPhone go out of range
				say_log "iPhone just left network"

				# perform action immediately when device left network
				action_left

				# set markers
				echo "0" > /tmp/iphone_present
				echo "1" > /tmp/iphone_grace_c
			else
				# State is known and same as before, let's count gracetime and...
				grace_c=$(cat /tmp/iphone_grace_c)
				if [ "$grace_c" -le "$grace_t" ]; then

						# counting of gracetime
						say_log "iPhone out of network [ grace time: $grace_c/$grace_t ]"
						grace_c=$((grace_c+1))
						echo "$grace_c" > /tmp/iphone_grace_c
					else
						# ...if we reach max $grace_t, let's perform some action here(once)
						is_action_done=$(cat /tmp/iphone_action)
						if [ "$is_action_done" -ne "1" ];then

								# perform action, yeah, once
								action_after_grace

								# send notification, so you are aware
								if [ "$boxcar_id" ]; then 
									boxcar_send
								fi

								# mark that this action was already performed, so we do not repeat it forever...
								echo "1" > /tmp/iphone_action 
							else
								# nobody here, just tellin
								say_log "iPhone out of network"

								# but maybe we still want to perform some actiion, like throw away anyone on ssh..
								action_away
						fi
				fi
		fi
fi