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 like OpenHAB to turn down the heating when everyone left the appartment.

Install the packages

• mosquitto-client
• coreutils-nohup

with either luci or opkg.

opkg update && opkg install libustream-openssl
wget -O /usr/bin/presence_report https://raw.githubusercontent.com/dersimn/owrtwifi2mqtt/master/presence_report && chmod u x /usr/bin/presence_report

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.

Place the following lines

nohup /usr/bin/presence_report event 192.168.1.2 >/dev/null 2>&1 &
nohup /usr/bin/presence_report lastseen 192.168.1.2 >/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.

If you are running more than one OpenWRT Router and want to collect data from both, you can specify an own base topic for each with:

MQTT_BASETOPIC="owrtwifi2" nohup /usr/bin/presence_report event 192.168.1.2 >/dev/null 2>&1 &
MQTT_BASETOPIC="owrtwifi2" nohup /usr/bin/presence_report lastseen 192.168.1.2 >/dev/null 2>&1 &

ENV variables for configuration are:

• MQTT_BASETOPIC: owrtwifi
• MQTT_STATUS_TOPIC: $MQTT_BASETOPIC/status/mac-
• MQTT_MAINTENANCE_TOPIC: $MQTT_BASETOPIC/maintenance
• MQTT_USER
• MQTT_PASSWORD
• MQTT_ID: $MQTT_BASETOPIC

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

owrtwifi/status/mac-00-00-00-00-00-00/lastseen/iso8601

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

owrtwifi/status/mac-00-00-00-00-00-00/lastseen/epoch

Unix epoch in seconds

owrtwifi/status/mac-00-00-00-00-00-00/event

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

Additionally the DHCP name (if available) from /tmp/dhcp.leases will be published to

owrtwifi/status/mac-00-00-00-00-00-00/dhcp-name

Original idea and script from Jupiter "belikh" Belic. Suggestion to use iw event from Tom "tomdee" Denham, merging these two scripts into one for easier installation by afreof.
This script follows Oliver "owagner" Wagner's architectural proposal for an mqtt-smarthome.