A simple shell script to detect presence of Wifi devices (smartphones, tablets, Amazon Dash Buttons, ..) and post the results via MQTT. This information can be processed in Homeautomation Systems to turn down the heating when everyone left the appartment.

Install the MQTT client on your Router

Install the packages with opkg opkg install mosquitto-client opkg install coreutils-nohup or with luci.

Copy over the script

Use SCP to copy the presence_report script to /usr/bin/presence_report on the target device. Call chmod u+x /usr/bin/presence_report to allow script execution.

Add the script to rc.local for autostart

Place the following lines

  • nohup /usr/bin/presence_report event >/dev/null 2>&1 &
  • nohup /usr/bin/presence_report lastseen >/dev/null 2>&1 &

inside the /etc/rc.local file before the exit 0. You can to this via command-line or via LuCI in System -> Startup -> Local Startup. The script will be executed after reboot.


After installation the following topics will be published for each WiFi device, using the lowercase MAC address:


Payload contains the timestamp when the device was seen in an ISO 8601 (and OpenHAB) compatible format, like this: 2017-08-25T19:29:57+0200


Unix epoch in seconds


Message will be new or del and is sent right after the device connected/disconnected to/from WiFi.





MQTT_ID_EVENT=“OpenWRT-Presence-Event” MQTT_ID_LASTSEEN=“OpenWRT-Presence-LastSeen” MQTT_TOPIC=“owrtwifi/status/mac-”

SCRIPT_NAME="$(basename “$(test -L “$0” && readlink “$0” || echo “$0”)")”

Parse command line args

test_for_mode(){ param_mode=$1 if [ “$param_mode” == “event” -o “$param_mode” == “lastseen” ]; then MODE=$param_mode return 0 fi return 1 }

test_for_ipv4(){ param_ip=$1 echo $param_ip | grep -E ‘\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(.|$)){4}\b’ > /dev/null if [ $? -eq 0 ]; then MQTT_SERVER=$param_ip return 0 fi return 1 }

test_for_update_periode_s(){ param_up=$1 expr $param_up : ‘[0-9][0-9]*$’ if [ $? -eq 0 ]; then LAST_SEEN_UPDATE_PERIOD_S=$param_up return 0 fi return 1 }

print_usage(){ cat « EOF Supported optional parameters: mode: “event” or “lastseen” (default: $DEFAULT_MODE) In event mode changes of registered mac addresses are imediately pushed to the MQTT server In lastseen mode the registered mac addresses are periodically pushed to the MQTT server MQTT server IP: the IPv4 address of the MQTT server (default $DEFAULT_MQTT_SERVER) Udate periode [s]: only relevant for lastseen mode (default $LAST_SEEN_UPDATE_PERIOD_S) Examples: $SCRIPT_NAME $SCRIPT_NAME $SCRIPT_NAME lastseen 300 EOF }

for param in “$@"; do test_for_mode $param ||
test_for_ipv4 $param ||
test_for_update_periode_s $param ||
{ print_usage; exit 1; } done

if [ “$MODE” == “event” ]; then echo “$SCRIPT_NAME, mode: $MODE, MQTT server: $MQTT_SERVER” iw event |
while read LINE; do if echo $LINE | grep -q -E “(new|del) station”; then EVENT=echo $LINE | awk '/(new|del) station/ {print $2}' MAC=echo $LINE | awk '/(new|del) station/ {print $4}'

  echo "Mac: $MAC did $EVENT"
  mosquitto_pub -h $MQTT_SERVER -i $MQTT_ID_EVENT -t "$MQTT_TOPIC${MAC//:/-}/event" -m $EVENT

done elif [ “$MODE” == “lastseen” ]; then echo “$SCRIPT_NAME, mode: $MODE, MQTT server: $MQTT_SERVER, period: $LAST_SEEN_UPDATE_PERIOD_S” while true do for interface in iw dev | grep Interface | cut -f 2 -s -d" " do # for each interface, get mac addresses of connected stations/clients maclist=iw dev $interface station dump | grep Station | cut -f 2 -s -d" " for mac in $maclist do echo “lastseen epoch ${mac//:/-} $(date +%s)” mosquitto_pub -h $MQTT_SERVER -i $MQTT_ID_LASTSEEN -t “$MQTT_TOPIC${mac//:/-}/lastseen/epoch” -m “$(date +%s)” -r echo “lastseen iso8601 ${mac//:/-} $(date +%Y-%m-%dT%H:%M:%S%z)” mosquitto_pub -h $MQTT_SERVER -i $MQTT_ID_LASTSEEN -t “$MQTT_TOPIC${mac//:/-}/lastseen/iso8601” -m “$(date +%Y-%m-%dT%H:%M:%S%z)” -r done done sleep ${LAST_SEEN_UPDATE_PERIOD_S} done fi

#!/usr/bin/env python
import paho.mqtt.client as mqtt
import os

def on_connect(client, userdata, flags, rc): print(“Connected with result code " + str(rc))


def on_message(client, userdata, msg): print(msg.topic + " " + str(msg.payload)) a = str(msg.payload)

if 'ff-ff-ff-ff-ff-ff' in msg.topic and 'new' in msg.payload:
    os.system("./speech.sh 'Sebastian join WiFi'")
elif 'ff-ff-ff-ff-ff-ff' in msg.topic and 'del' in msg.payload:
    os.system("./speech.sh 'Sebastian leave WiFi'")

    if a == 'new':
        os.system("espeak 'Unknown client join WiFi'")
    elif a == 'del':
    os.system("espeak 'Unknown client leave WiFi'")

client = mqtt.Client() client.on_connect = on_connect client.on_message = on_message

client.connect(“localhost”, 1883, 60)